Center on Stress and Health

Dissociation

Bell, M. J., K. C. Lau, et al. (2007). "Characterization of the methoxy carbonyl radical formed via photolysis of methyl chloroformate at 193.3 nm." J Phys Chem A 111(10): 1762-70.
This study investigates two features of interest in recent work on the photolytic production of the methoxy carbonyl radical and its subsequent unimolecular dissociation channels. Earlier studies used methyl chloroformate as a photolytic precursor for the CH3OCO, methoxy carbonyl (or methoxy formyl) radical, which is an intermediate in many reactions that are relevant to combustion and atmospheric chemistry. That work evidenced two competing C-Cl bond fission channels, tentatively assigning them as producing ground- and excited-state methoxy carbonyl radicals. In this study, we measure the photofragment angular distributions for each C-Cl bond fission channel and the spin-orbit state of the Cl atoms produced. The data shows bond fission leading to the production of ground-state methoxy carbonyl radicals with a high kinetic energy release and an angular distribution characterized by an anisotropy parameter, beta, of between 0.37 and 0.64. The bond fission that leads to the production of excited-state radicals, with a low kinetic energy release, has an angular distribution best described by a negative anisotropy parameter. The very different angular distributions suggest that two different excited states of methyl chloroformate lead to the formation of ground- and excited-state methoxy carbonyl products. Moreover, with these measurements we were able to refine the product branching fractions to 82% of the C-Cl bond fission resulting in ground-state radicals and 18% resulting in excited-state radicals. The maximum kinetic energy release of 12 kcal/mol measured for the channel producing excited-state radicals suggests that the adiabatic excitation energy of the radical is less than or equal to 55 kcal/mol, which is lower than the 67.8 kcal/mol calculated by UCCSD(T) methods in this study. The low-lying excited states of methylchloroformate are also considered here to understand the observed angular distributions. Finally, the mechanism for the unimolecular dissociation of the methoxy carbonyl radical to CH3 + CO2, which can occur through a transition state with either cis or, with a much higher barrier, trans geometry, was investigated with natural bond orbital computations. The results suggest donation of electron density from the nonbonding C radical orbital to the sigma* orbital of the breaking C-O bond accounts for the additional stability of the cis transition state.

Krisch, M. J., M. J. Bell, et al. (2007). "Photodissociation pathways of 1,1-dichloroacetone." J Phys Chem A 111(27): 5968-80.
We present a comprehensive investigation of the dissociation dynamics following photoexcitation of 1,1-dichloroacetone (CH(3)COCHCl(2)) at 193 nm. Two major dissociation channels are observed: cleavage of a C-Cl bond to form CH(3)C(O)CHCl + Cl and elimination of HCl. The branching between these reaction channels is roughly 9:1. The recoil kinetic energy distributions for both C-Cl fission and HCl elimination are bimodal. The former suggests that some of the radicals are formed in an excited electronic state. A portion of the CH(3)C(O)CHCl photoproducts undergo secondary dissociation to give CH(3) + C(O)CHCl. Photoelimination of Cl(2) is not a significant product channel. A primary C-C bond fission channel to give CH(3)CO + CHCl(2) may be present, but this signal may also be due to a secondary dissociation. Data from photofragment translational spectroscopy with electron impact and photoionization detection, velocity map ion imaging, and UV-visible absorption spectroscopy are presented, along with G3//B3LYP calculations of the bond dissociation energetics.

Lee, J. S., D. Spiegel, et al. (2007). "Fractal analysis of EEG in hypnosis and its relationship with hypnotizability." Int J Clin Exp Hypn 55(1): 14-31.
Fractal analysis was applied to study the trends of EEG signals in the hypnotic condition. The subjects were 19 psychiatric outpatients. Hypnotizability was measured with the Hypnotic Induction Profile (HIP). Fifty-four sets of EEG data were analyzed by detrended fluctuation analysis (DFA), a well-established fractal analysis technique. The scaling exponents, which are the results of fractal analysis, are reduced toward white noise during the hypnotic condition, which differentiates the hypnotic condition from the waking condition. Further, the decrease in the scaling exponents during hypnosis was solely associated with the eye-roll sign within specific cortical areas (F3, C4, and O1/2) closely related to eye movements and attention. In conclusion, the present study has found that the application of the fractal analysis technique can demonstrate the electrophysiological correlations with hypnotic influence on cerebral activity.

Butler, L. D. (2006). "Normative dissociation." Psychiatr Clin North Am 29(1): 45-62, viii.

Ginzburg, K., C. Koopman, et al. (2006). "Evidence for a dissociative subtype of post-traumatic stress disorder among help-seeking childhood sexual abuse survivors." J Trauma Dissociation 7(2): 7-27.
This study examined evidence for a dissociative subtype of post-traumatic stress disorder (PTSD) among women seeking psychotherapy for childhood sexual abuse (CSA). One hundred and twenty-two women seeking treatment for CSA completed a battery of questionnaires assessing PTSD, dissociative symptoms, and child maltreatment. Using signal detection analysis, we identified high and low dissociation PTSD subgroups. A constellation of three PTSD symptoms-hypervigilance, sense of foreshortened future, and sleep difficulties-discriminated between these two subgroups (OR = 8.15). Further evidence was provided by the finding of a nonlinear relationship between severity of childhood maltreatment and dissociation in the women with PTSD. These results provide support for a dissociative subtype of PTSD that may stem from more severe childhood experiences of neglect and abuse.

Liu, Y., K. C. Lau, et al. (2006). "Photodissociation of cyclobutyl bromide at 234 nm studied using velocity map imaging." J Phys Chem A 110(16): 5379-85.
This study investigates the 234 nm photodissociation dynamics of cyclobutyl bromide using a two-dimensional photofragment velocity imaging technique. The spin-orbit ground- and excited-state Br(2P) atoms are state-selectively detected via [2+1] resonance enhanced multiphoton ionization (REMPI), whereas the cyclobutyl radicals are ionized using 157 nm laser light. The Br(2P(3/2)) and the Br(2P(1/2)) atoms and their c-C4H7 radical cofragments evidence a single-peaked, Gaussian-shaped translational energy distribution ranging from approximately 14 to approximately 39 kcal/mol and angular distributions with significant parallel character. The Br(2P(1/2))/ Br(2P(3/2)) spin-orbit branching ratio is determined to be 0.11 +/- 0.07 by momentum match between the Br(2P) photofragments and the recoiling c-C4H7 fragments, assuming a uniform photoionization probability of the c-C4H7 radicals with an internal energy range of 10-35 kcal/mol. The REMPI line strength ratio for the detection of Br(2P(3/2)) and Br(2P(1/2)) atoms at 233.681 and 234.021 nm, respectively, is therefore derived to be 0.10 +/- 0.07. The measured recoil kinetic energies of the c-C4H7 radicals, and the resulting distribution of internal energies, indicates some of the radicals are formed with total internal energies above the barrier to isomerization and subsequent dissociation, but our analysis indicates they may be stable due to the substantial fraction of the internal energy which is partitioned to rotational energy of the radicals.

McCunn, L. R., B. L. FitzPatrick, et al. (2006). "Unimolecular dissociation of the propargyl radical intermediate of the CH+C2H2 and C+C2H3 reactions." J Chem Phys 125(13): 133306.
This paper examines the unimolecular dissociation of propargyl (HCCCH2) radicals over a range of internal energies to probe the CH+HCCH and C+C2H3 bimolecular reactions from the radical intermediate to products. The propargyl radical was produced by 157 nm photolysis of propargyl chloride in crossed laser-molecular beam scattering experiments. The H-loss and H2 elimination channels of the nascent propargyl radicals were observed. Detection of stable propargyl radicals gave an experimental determination of 71.5 (+5-10) kcal/mol as the lowest barrier to dissociation of the radical. This barrier is significantly lower than predictions for the lowest barrier to the radical's dissociation and also lower than calculated overall reaction enthalpies. Products from both H2+HCCC and H+C3H2 channels were detected at energies lower than what has been theoretically predicted. An HCl elimination channel and a minor C-H fission channel were also observed in the photolysis of propargyl chloride.

McCunn, L. R., K. C. Lau, et al. (2006). "Unimolecular dissociation of the CH3OCO radical: an intermediate in the CH3O + CO reaction." J Phys Chem A Mol Spectrosc Kinet Environ Gen Theory 110(4): 1625-34.
This work investigates the unimolecular dissociation of the methoxycarbonyl, CH(3)OCO, radical. Photolysis of methyl chloroformate at 193 nm produces nascent CH(3)OCO radicals with a distribution of internal energies, determined by the velocities of the momentum-matched Cl atoms, that spans the theoretically predicted barriers to the CH(3)O + CO and CH(3) + CO(2) product channels. Both electronic ground- and excited-state radicals undergo competitive dissociation to both product channels. The experimental product branching to CH(3) + CO(2) from the ground-state radical, about 70%, is orders of magnitude larger than Rice-Ramsperger-Kassel-Marcus (RRKM)-predicted branching, suggesting that previously calculated barriers to the CH(3)OCO --> CH(3) + CO(2) reaction are dramatically in error. Our electronic structure calculations reveal that the cis conformer of the transition state leading to the CH(3) + CO(2) product channel has a much lower barrier than the trans transition state. RRKM calculations using this cis transition state give product branching in agreement with the experimental branching. The data also suggest that our experiments produce a low-lying excited state of the CH(3)OCO radical and give an upper limit to its adiabatic excitation energy of 55 kcal/mol.

Spiegel, D. (2006). "Recognizing traumatic dissociation." Am J Psychiatry 163(4): 566-8.

Spiegel, D. (2006). "Reduced hippocampal and amygdalar volume in dissociative identity disorder: not such clear evidence." Am J Psychiatry 163(11): 2014.

Wong, M., E. Looney, et al. (2006). "A preliminary study of peritraumatic dissociation, social support, and coping in relation to posttraumatic stress symptoms for a parent's cancer." Psychooncology 15(12): 1093-8.
This study examined predictors of posttraumatic stress disorder (PTSD) symptoms in adults who, as children, had a parent diagnosed with cancer. Possible predictors of adulthood PTSD examined were peritraumatic dissociation, satisfaction with social support, coping through denial, behavioral disengagement and self-distraction, and whether or not the parent died. Thirty research participants (20 women and 10 men, ages 18-38) were recruited who were 8-17-years old at the time of a parent's cancer diagnosis. Each participant completed measures of their current PTSD symptoms in response to their parent's cancer, peritraumatic dissociative experiences, demographic characteristics, and satisfaction with social support and use of coping strategies at the time of their parent's cancer diagnosis. Seventeen percent met screening criteria for likely PTSD. As hypothesized, PTSD symptoms were strongly and positively correlated with peritraumatic dissociation. Furthermore, PTSD symptoms were greater among females and were related to greater use of denial and behavioral disengagement and to less satisfaction with social support. These results suggest that health care providers need to recognize symptoms of peritraumatic dissociation in the children of parents who are diagnosed with cancer so that steps can be taken to minimize the children's development of PTSD that may extend into their adult lives.

Lau, K. C., Y. Liu, et al. (2005). "Probing the barrier for CH2CHCO --> CH2CH + CO by the velocity map imaging method." J Chem Phys 123(5): 054322.
This work determines the dissociation barrier height for CH2CHCO --> CH2CH + CO using two-dimensional product velocity map imaging. The CH2CHCO radical is prepared under collision-free conditions from C-Cl bond fission in the photodissociation of acryloyl chloride at 235 nm. The nascent CH2CHCO radicals that do not dissociate to CH2CH + CO, about 73% of all the radicals produced, are detected using 157-nm photoionization. The Cl(2P(3/2)) and Cl(2P(1/2)) atomic fragments, momentum matched to both the stable and unstable radicals, are detected state selectively by resonance-enhanced multiphoton ionization at 235 nm. By comparing the total translational energy release distribution P(E(T)) derived from the measured recoil velocities of the Cl atoms with that derived from the momentum-matched radical cophotofragments which do not dissociate, the energy threshold at which the CH2CHCO radicals begin to dissociate is determined. Based on this energy threshold and conservation of energy, and using calculated C-Cl bond energies for the precursor to produce CH2CHC*O or C*H2CHCO, respectively, we have determined the forward dissociation barriers for the radical to dissociate to vinyl + CO. The experimentally determined barrier for CH2CHC*O --> CH2CH + CO is 21+/-2 kcal mol(-1), and the computed energy difference between the CH2CHC*O and the C*H2CHCO forms of the radical gives the corresponding barrier for C*H2CHCO --> CH2CH + CO to be 23+/-2 kcal mol(-1). This experimental determination is compared with predictions from electronic structure methods, including coupled-cluster, density-functional, and composite Gaussian-3-based methods. The comparison shows that density-functional theory predicts too low an energy for the C*H2CHCO radical, and thus too high a barrier energy, whereas both the Gaussian-3 and the coupled-cluster methods yield predictions in good agreement with experiment. The experiment also shows that acryloyl chloride can be used as a photolytic precursor at 235 nm of thermodynamically stable CH2CHC*O radicals, most with an internal energy distribution ranging from approximately 3 to approximately 21 kcal mol(-1). We discuss the results with respect to the prior work on the O(3P) + propargyl reaction and the analogous O(3P) + allyl system.

McCunn, L. R., M. J. Krisch, et al. (2005). "A study of the unimolecular dissociation of the 2-buten-2-yl radical via the 193 nm photodissociation of 2-chloro-2-butene." J Phys Chem A 109(29): 6430-9.
This work investigates the unimolecular dissociation of the 2-buten-2-yl radical. This radical has three potentially competing reaction pathways: C-C fission to form CH3 + propyne, C-H fission to form H + 1,2-butadiene, and C-H fission to produce H + 2-butyne. The experiments were designed to probe the branching to the three unimolecular dissociation pathways of the radical and to test theoretical predictions of the relevant dissociation barriers. Our crossed laser-molecular beam studies show that 193 nm photolysis of 2-chloro-2-butene produces 2-buten-2-yl in the initial photolytic step. A minor C-Cl bond fission channel forms electronically excited 2-buten-2-yl radicals and the dominant C-Cl bond fission channel produces ground-state 2-buten-2-yl radicals with a range of internal energies that spans the barriers to dissociation of the radical. Detection of the stable 2-buten-2-yl radicals allows a determination of the translational, and therefore internal, energy that marks the onset of dissociation of the radical. The experimental determination of the lowest-energy dissociation barrier gave 31 +/- 2 kcal/mol, in agreement with the 32.8 +/- 2 kcal/mol barrier to C-C fission at the G3//B3LYP level of theory. Our experiments detected products of all three dissociation channels of unstable 2-buten-2-yl as well as a competing HCl elimination channel in the photolysis of 2-chloro-2-butene. The results allow us to benchmark electronic structure calculations on the unimolecular dissociation reactions of the 2-buten-2-yl radical as well as the CH3 + propyne and H + 1,2-butadiene bimolecular reactions. They also allow us to critique prior experimental work on the H + 1,2-butadiene reaction.

Miller, J. L., M. J. Krisch, et al. (2005). "Dissociation channels of the 1-buten-2-yl radical and its photolytic precursor 2-bromo-1-butene." J Phys Chem A Mol Spectrosc Kinet Environ Gen Theory 109(18): 4038-48.
The work presented here is the first in a series of studies that use a molecular beam scattering technique to investigate the unimolecular reaction dynamics of C(4)H(7) radical isomers. Photodissociation of the halogenated precursor 2-bromo-1-butene at 193 nm under collisionless conditions produced 1-buten-2-yl radicals with a range of internal energies spanning the predicted barriers to the unimolecular reaction channels of the radical. Resolving the velocities of the stable C(4)H(7) radicals, as well as those of the products, allows for the identification of the energetic onset of each dissociation channel. The data show that radicals with at least 30.7 +/- 2 kcal/mol of internal energy underwent C-C fission to form allene + methyl, and radicals with at least 36.7 +/- 4 kcal/mol of internal energy underwent C-H fission to form H + 1-butyne and H + 1,2-butadiene; both of these observed barriers agree well with the G3//B3LYP calculations of Miller. HBr elimination from the parent molecule was observed, producing vibrationally excited 1-butyne and 1,2-butadiene. In the subsequent dissociation of these C(4)H(6) isomers, the major channel was C-C fission to form propargyl + methyl, and there is also evidence of at least one of the possible H + C(4)H(5) channels. A minor C-Br fission channel produces 1-buten-2-yl radicals in an excited electronic state and with low kinetic energy; these radicals exhibit markedly different dissociation dynamics than do the radicals produced in their ground electronic state.

Kalichman, S. C., C. Gore-Felton, et al. (2004). "Trauma symptoms, sexual behaviors, and substance abuse: correlates of childhood sexual abuse and HIV risks among men who have sex with men." J Child Sex Abus 13(1): 1-15.
Childhood sexual abuse is associated with high-risk sexual behavior in men who have sex with men. This study examined psychological and behavioral correlates of HIV risk behavior associated with childhood sexual abuse in a sample of men who have sex with men. Men attending a large gay pride event (N = 647) completed anonymous surveys that assessed demographic characteristics, childhood sexual abuse history, symptoms of dissociation and trauma-related anxiety, borderline personality characteristics, substance use, and sexual risk behavior. Results indicated that men who have a history of childhood sexual abuse were more likely to: engage in high-risk sexual behavior (i.e., unprotected receptive anal intercourse), trade sex for money or drugs, report being HIV positive, and experience non-sexual relationship violence. Results of this study extend previous research to show that men who have sex with men and who have a history of child sexual abuse are more likely to be at high risk for HIV infection.

Koopman, C., V. Carrion, et al. (2004). "Relationships of dissociation and childhood abuse and neglect with heart rate in delinquent adolescents." J Trauma Stress 17(1): 47-54.
This study examined the relationship of dissociative symptoms, abuse and neglect, and gender to mean heart rate (HR) in two types of interviews. Participants were 25 female and 16 male delinquent adolescents. Dissociative symptoms and abuse and neglect were assessed by structured interviews. Participants were randomized to one of two conditions, to describe either their most stressful life experience or their free association thoughts. Greater dissociative symptoms were associated with lower mean HR, whereas abuse and neglect, being a girl, and participating in the free association task were associated with higher mean HR. The finding that high levels of dissociative symptoms may be related to a suppression of autonomic physiological responses to stress support Bremner's conceptualization (J. D. Bremner, 1999) that dissociative symptoms comprise one of two subtypes of the acute stress response, differing physiologically as well as subjectively from a predominantly hyperarousal or intrusive symptom response.

Liu, Y. and L. J. Butler (2004). "C-Cl bond fission dynamics and angular momentum recoupling in the 235 nm photodissociation of allyl chloride." J Chem Phys 121(22): 11016-22.
The photodissociation dynamics of allyl chloride at 235 nm producing atomic Cl((2)P(J);J=1/2,3/2) fragments is investigated using a two-dimensional photofragment velocity ion imaging technique. Detection of the Cl((2)P(1/2)) and Cl((2)P(3/2)) products by [2+1] resonance enhanced multiphoton ionization shows that primary C-Cl bond fission of allyl chloride generates 66.8% Cl((2)P(3/2)) and 33.2% Cl((2)P(1/2)). The Cl((2)P(3/2)) fragments evidenced a bimodal translational energy distribution with a relative weight of low kinetic energy Cl((2)P(3/2))/high kinetic energy Cl((2)P(3/2)) of 0.097/0.903. The minor dissociation channel for C-Cl bond fission, producing low kinetic energy chlorine atoms, formed only chlorine atoms in the Cl((2)P(3/2)) spin-orbit state. The dominant C-Cl bond fission channel, attributed to an electronic predissociation that results in high kinetic energy Cl atoms, produced both Cl((2)P(1/2)) and Cl((2)P(3/2)) atomic fragments. The relative branching for this dissociation channel is Cl((2)P(1/2))/[Cl((2)P(1/2))+Cl((2)P(3/2))]=35.5%. The average fraction of available energy imparted into product recoil for the high kinetic energy products was found to be 59%, in qualitative agreement with that predicted by a rigid radical impulsive model. Both the spin-orbit ground and excited chlorine atom angular distributions were close to isotropic. We compare the observed Cl((2)P(1/2))/[Cl((2)P(1/2))+Cl((2)P(3/2))] ratio produced in the electronic predissociation channel of allyl chloride with a prior study of the chlorine atom spin-orbit states produced from HCl photodissociation, concluding that angular momentum recoupling in the exit channel at long interatomic distance determines the chlorine atom spin-orbit branching.

Miller, J. L., L. R. McCunn, et al. (2004). "Dissociation of the ground state vinoxy radical and its photolytic precursor chloroacetaldehyde: electronic nonadiabaticity and the suppression of the H+ketene channel." J Chem Phys 121(4): 1830-8.
This work is a study of the competition between the two unimolecular reaction channels available to the vinoxy radical (CH(2)CHO), C-H fission to form H+ketene, and isomerization to the acetyl radical (CH(3)CO) followed by C-C fission to form CH(3) + CO. Chloroacetaldehyde (CH(2)ClCHO) was used as a photolytic precursor to the vinoxy radical in its ground state; photodissociation of chloroacetaldehyde at 193 nm produces vinoxy radicals with internal energies spanning the G3//B3LYP calculated barriers to the two available unimolecular reaction channels. The onset of the CH(3) + CO channel, via isomerization to the acetyl radical, was found to occur at an internal energy of 41 +/- 2 kcal/mol, agreeing well with our calculated isomerization barrier of 40.8 kcal/mol. Branching to the H+ketene channel was too small to be detected; we conclude that the branching to the H+ketene channel must be at least a factor of 200 lower than what is predicted by a RRKM analysis based on our electronic structure calculations. This dramatic result may be explained in part by the presence of a conical intersection at planar geometries along the reaction coordinate leading to H+ketene, which results in electronically nonadiabatic recrossing of the transition state.

Szpunar, D. E., J. L. Miller, et al. (2004). "193-nm photodissociation of acryloyl chloride to probe the unimolecular dissociation of CH2CHCO radicals and CH2CCO." J Chem Phys 120(9): 4223-30.
The work presented here uses photofragment translational spectroscopy to investigate the primary and secondary dissociation channels of acryloyl chloride (CH2==CHCOCl) excited at 193 nm. Three primary channels were observed. Two C-Cl fission channels occur, one producing fragments with high kinetic recoil energies and the other producing fragments with low translational energies. These channels produced nascent CH2CHCO radicals with internal energies ranging from 23 to 66 kcal/mol for the high-translational-energy channel and from 50 to 68 kcal/mol for the low-translational-energy channel. We found that all nascent CH2CHCO radicals were unstable to CH2CH + CO formation, in agreement with the G3//B3LYP barrier height of 22.4 kcal/mol to within experimental and computational uncertainties. The third primary channel is HCl elimination. All of the nascent CH2CCO coproducts were found to have enough internal energy to dissociate, producing CH2C: + CO, in qualitative agreement with the G3//B3LYP barrier of 39.5 kcal/mol. We derive from the experimental results an upper limit of 23 +/- 3 kcal/mol for the zero-point-corrected barrier to the unimolecular dissociation of the CH2CHCO radical to form CH2CH + CO.

Steiner, H., V. Carrion, et al. (2003). "Dissociative symptoms in posttraumatic stress disorder: diagnosis and treatment." Child Adolesc Psychiatr Clin N Am 12(2): 231-49, viii.
This article explores the complex relationship between dissociation and psychiatric trauma. Dissociation is described as a defense reaction, a risk factor for the development of posttraumatic stress disorder, and as a set of syndromal disturbances. The authors discuss various models proposed for the relationship between these. They outline developmental considerations in diagnosis and treatment and end by discussing further needed research.

Butler, L. D. (2000). "New DSM-IV diagnosis of acute stress disorder." Am J Psychiatry 157(11): 1889, author reply 1890-1.

Cardena, E., C. Koopman, et al. (2000). "Psychometric properties of the Stanford Acute Stress Reaction Questionnaire (SASRQ): a valid and reliable measure of acute stress." J Trauma Stress 13(4): 719-34.
A reliable and valid measure is needed for assessing the psychological symptoms experienced in the aftermath of a traumatic event. Previous research suggests that trauma victims typically experience dissociative, anxiety and other symptoms, during or shortly after a traumatic event. Although some of these symptoms may protect the trauma victim from pain, they may also lead to acute stress, posttraumatic stress, or other disorders. The Stanford Acute Stress Reaction Questionnaire (SASRQ) was developed to evaluate anxiety and dissociation symptoms in the aftermath of traumatic events, following DSM-IV criteria for acute stress disorder. We present data from multiple datasets and analyses supporting the reliability and construct, convergent, discriminant, and predictive validity of the SASRQ.

Koopman, C. (2000). "New DSM-IV diagnosis of acute stress disorder." Am J Psychiatry 157(11): 1888; author reply 1890-1.

Spiegel, D., C. Classen, et al. (2000). "New DSM-IV diagnosis of acute stress disorder." Am J Psychiatry 157(11): 1890-1.

Spiegel, D. (1999). "Commentary: deconstructing self-destruction." Psychiatry 62(4): 329-30.

Butler, L. J. (1998). "Chemical reaction dynamics beyond the Born-Oppenheimer approximation." Annu Rev Phys Chem 49: 125-71.
To predict the branching between energetically allowed product channels, chemists often rely on statistical transition state theories or exact quantum scattering calculations on a single adiabatic potential energy surface. The potential energy surface gives the energetic barriers to each chemical reaction and allows prediction of the reaction rates. Yet, chemical reactions evolve on a single potential energy surface only if, in simple terms, the electronic wavefunction can evolve from the reactant electronic configuration to the product electronic configuration on a time scale that is fast compared to the nuclear dynamics through the transition state. The experiments reviewed here investigate how the breakdown of the Born-Oppenheimer approximation at a barrier along an adiabatic reaction coordinate can alter the dynamics of and the expected branching between molecular dissociation pathways. The work reviewed focuses on three questions that have come to the forefront with recent theory and experiments: Which classes of chemical reactions evidence dramatic nonadiabatic behavior that influences the branching between energetically allowed reaction pathways? How do the intramolecular distance and orientation between the electronic orbitals involved influence the nonadiabaticity in the reaction? How can the detailed nuclear dynamics mediate the effective nonadiabatic coupling encountered in a chemical reaction?

DeBattista, C., H. B. Solvason, et al. (1998). "ECT in dissociative identity disorder and comorbid depression." J Ect 14(4): 275-9.
Dissociative identity disorder (DID), previously named multiple personality disorder, is a diagnosis often complicated by comorbid major depression. We report on four cases of DID associated with severe self-destructive behavior and comorbid major depression treated with electroconvulsive therapy (ECT). In three of the patients, ECT appeared to be helpful in treating the comorbid depression without adversely affecting the DID. The potential risks of using ECT in patients with DID are reviewed.

Spiegel, D. (1998). "Hypnosis and implicit memory: automatic processing of explicit content." Am J Clin Hypn 40(3): 231-40.
Kenneth S. Bowers, in whose honor this issue is written, was, in his own words, "seriously curious" (Bowers, 1983 (originally published 1976)) about hypnosis throughout his career. He brought a lively intellect and an engaging and lucid writing style reminiscent of Freud's (forgive me, Ken, I'm referring to style, not content), and a set of serious questions to the phenomenon of hypnosis. We are indebted to him for his many contributions to the field.

Spiegel, D. (1997). "Trauma, dissociation, and memory." Ann N Y Acad Sci 821: 225-37.

Butler, L. D., R. E. Duran, et al. (1996). "Hypnotizability and traumatic experience: a diathesis-stress model of dissociative symptomatology." Am J Psychiatry 153(7 Suppl): 42-63.
OBJECTIVE: The authors propose a diathesis-stress model to describe how pathological dissociation may arise from an interaction between innate hypnotizability and traumatic experience. METHOD: To support the proposition that pathological dissociation may reflect autohypnotic process, the authors highlight clinical and research data indicating parallels between controlled hypnotic dissociative states and uncontrolled pathological dissociative symptoms and summarize evidence of hypnotizability in persons with psychiatric disorders that manifest these symptoms. The authors present this evidence by examining dissociative symptomatology in four psychological domains: perception, behavior and will, affect, and memory and identity. In addition, modern cognitive and neuropsychological models of dissociation are briefly reviewed. RESULTS: Several lines of evidence converge in support of the role of autohypnosis in pathological dissociation. There is considerable evidence that controlled formal hypnosis can produce a variety of dissociations of awareness and control that resemble many of the symptoms in uncontrolled pathological dissociative conditions; and it is possible to discern in dissociative pathology the features of absorption, dissociation, and suggestibility/automaticity that characterize formal hypnotic states. There is also accumulating evidence of high levels of hypnotic capacity in all groups with dissociative symptomatology that have been systematically assessed. In addition, the widespread and successful therapeutic use of hypnosis in the treatment of many dissociative symptoms and conditions (and the potential for hypnosis to induce dissociative symptomatology) also supports the assumption that hypnosis and pathological dissociation share an underlying process. CONCLUSIONS: High hypnotizability may be a diathesis for pathological dissociative states, particularly under conditions of acute traumatic stress.

Koopman, C., C. Classen, et al. (1996). "Dissociative responses in the immediate aftermath of the Oakland/Berkeley firestorm." J Trauma Stress 9(3): 521-40.
This study examined relationships between dissociative symptoms experienced in the immediate aftermath of the Oakland/Berkeley firestorm and contact with the fire, life events, demographic variables, and actions taken after learning about the fire. One hundred eighty-seven participants completed self-report measures about their experiences during and immediately following the fire. Dissociative symptoms were significantly related to contact with the fire, sex, and stressful life events. Also, dissociative symptoms were significantly related to engaging in certain activities, such as trying to get closer to the fire and going into blocked-off areas and crossing police barricades. These results suggest that dissociative symptoms may merit special attention in intervention focusing on the immediate aftermath of disaster.

Koopman, C., C. Classen, et al. (1995). "When disaster strikes, acute stress disorder may follow." J Trauma Stress 8(1): 29-46.
During and immediately following a traumatic event, people may manifest a pattern of dissociative and anxiety symptoms and other reactions, referred to as Acute Stress Disorder. A review of the empirical literature on psychological reactions to trauma suggest that this pattern of symptoms has often been identified across different kinds of traumatic events. It is likely to constitute a psychological adaptation to a stressful event, limiting painful thoughts and feelings associated with the event and allowing the person to function at least minimally. Continuation of these symptoms, however, may impair the person's quality of life and disrupt social and other functioning. If symptoms last beyond a month following the traumatic event, Post Traumatic Stress Disorder (PTSD) may ensue, continuing for months or even years after the precipitating event. Hence, it is important to be able to identify this pattern of reactions that may be manifested in reaction to trauma, so that appropriate intervention can be provided. Although it was not officially recognized in the 3rd edition Diagnostic and Statistical Manual (DSM-III-R), Acute Stress Disorder is included as a separate diagnosis in the DSM-IV.

Spiegel, D. (1995). "Psychiatry disabused." Nat Med 1(6): 490-1; author reply.

Freinkel, A., C. Koopman, et al. (1994). "Dissociative symptoms in media eyewitnesses of an execution." Am J Psychiatry 151(9): 1335-9.
OBJECTIVE: The first execution in California since 1976 took place recently in the San Quentin Prison gas chamber. Eighteen journalists were invited as media eyewitnesses. The authors postulated that witnessing this execution was psychologically traumatic and that dissociative and anxiety symptoms would be experienced by the journalists. METHOD: To investigate the prevalence and specific nature of these symptoms, questionnaires were sent to all the journalists about a month after the execution. The questionnaire contained 17 items assessing dissociative symptoms from the authors' questionnaire of 35 highly intercorrelated acute stress items. Fifteen of 18 of the witnesses returned the questionnaire. Items were endorsed on a scale of 0 ("have not experienced") to 5 ("very often experienced") and analyzed as being dichotomously present or absent. The mean age of the respondents was 37.6 (SD = 8.6) and mean years as a journalist were 15.2 (SD = 9.0). Nine subjects were men and six were women. RESULTS: Journalists witnessing the execution endorsed an average of 5.0 dissociative items, ranging from "I saw, heard, or felt things that were not really there" (endorsed by no one) to "I felt estranged or detached from other people" (endorsed by 60%). This prevalence of reported dissociative symptoms is comparable to that seen among persons who endured the recent Oakland/Berkeley, Calif., firestorm. CONCLUSIONS: The experience of being an eyewitness to an execution was associated with the development of dissociative symptoms in several journalists.

Koopman, C., C. Classen, et al. (1994). "Predictors of posttraumatic stress symptoms among survivors of the Oakland/Berkeley, Calif., firestorm." Am J Psychiatry 151(6): 888-94.
OBJECTIVE: The purpose of this study was to examine factors predicting the development of posttraumatic stress symptoms after a traumatic event, the 1991 Oakland/Berkeley firestorm. The major predictive factors of interest were dissociative, anxiety, and loss of personal autonomy symptoms reported in the immediate aftermath of the fire; contact with the fire; and life stressors before and after the fire. METHOD: Subjects were recruited from several sources so that they would vary in their extent of contact with the fire. Of 187 participants who completed self-report measures about their experiences in the aftermath of the firestorm, 154 completed a follow-up assessment. Of these 154 subjects, 97% completed the follow-up questionnaires 7-9 months after the fire. The questionnaires included measures of posttraumatic stress and life events since the fire. RESULTS: Dissociative and loss of personal autonomy symptoms experienced in the fire's immediate aftermath, as well as stressful life experiences occurring later, significantly predicted posttraumatic stress symptoms measured 7-9 months after the firestorm by a civilian version of the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder and the Impact of Event Scale. Dissociative symptoms more strongly predicted posttraumatic symptoms than did anxiety and loss of personal autonomy symptoms. Intrusive thinking differs from other kinds of posttraumatic symptoms in being related directly to the trauma and previous stressful life events. CONCLUSIONS: These findings suggest that dissociative symptoms experienced in the immediate aftermath of a traumatic experience and subsequent stressful experiences are indicative of risk for the later development of posttraumatic stress symptoms. Such measures may be useful as screening procedures for identifying those most likely to need clinical care to help them work through their reactions to the traumatic event and to subsequent stressful experiences.

Spiegel, D. and A. W. Scheflin (1994). "Dissociated or fabricated? Psychiatric aspects of repressed memory in criminal and civil cases." Int J Clin Exp Hypn 42(4): 411-32.
During the last decade, clinicians, courts, and researchers have been faced with exceedingly difficult questions involving the crossroads where memory, traumatic memory, dissociation, repression, childhood sexual abuse, and suggestion all meet. In one criminal case, repressed memories served as the basis for a conviction of murder. In approximately 50 civil cases, courts have ruled on the issue of whether repressed memory for childhood sexual abuse may form the basis of a suit against the alleged perpetrators. Rulings that have upheld such use underscore the importance of the reliability of memory retrieval techniques. Hypnosis and other methodologies employed in psychotherapy may be beneficial in working through memories of trauma, but they may also distort memories or alter a subject's evaluation of their veracity. Because of the reconstructive nature of memory, caution must be taken to treat each case on its own merits and avoid global statements essentially proclaiming either that repressed memory is always right or that it is always wrong.

Cardena, E. and D. Spiegel (1993). "Dissociative reactions to the San Francisco Bay Area earthquake of 1989." Am J Psychiatry 150(3): 474-8.
OBJECTIVE: This study systematically evaluated the psychological reactions of a nonclinical population to the October 1989 earthquake in the San Francisco Bay Area. METHOD: A representative group of about 100 graduate students from two different institutions in the Bay Area volunteered to participate in the study. Within 1 week of the earthquake, the authors administered a checklist of anxiety and dissociative symptoms to the subjects, and 4 months later they conducted a follow-up study with the same checklist. RESULTS: The participants reported significantly greater numbers and frequency of dissociative symptoms, including derealization and depersonalization, distortions of time, and alterations in cognition, memory and somatic sensations, during or shortly after the earthquake than after 4 months. To a lesser degree they also reported significantly more nonsomatic anxiety symptoms and Schneider's first-rank symptoms at the earlier testing time. CONCLUSIONS: These results suggest that among nonclinical populations, extreme distress may significantly increase the prevalence and severity of transient dissociative phenomena and anxiety. They provide further evidence of the role that dissociation plays in the response to trauma and are of considerable clinical and theoretical importance in view of the lifetime prevalence of traumatic experiences in the general population.

Classen, C., C. Koopman, et al. (1993). "Trauma and dissociation." Bull Menninger Clin 57(2): 178-94.
The stress associated with experiencing or witnessing physical trauma can cause abrupt and marked alterations in mental state, including anxiety and transient dissociative symptoms. Intense manifestations of this pattern of response to trauma are described in a new diagnostic category proposed for DSM-IV: acute stress disorder. Severe dissociative symptoms may predict subsequent posttraumatic stress disorder. Persons who experience a series of traumatic events may be especially vulnerable to a variety of dissociative states, including amnesia, fugue, depersonalization, and multiple personality disorder. Treatment for these symptoms emphasizes strengthening supportive interpersonal relationships and developing insight that reduces psychological pain by integrating the trauma into a meaningful, less self-blaming perspective.

Spiegel, D. (1993). "Multiple personality." Br J Psychiatry 162: 126.

Jaschke, V. A. and D. Spiegel (1992). "A case of probable dissociative disorder." Bull Menninger Clin 56(2): 246-60.
The case of a patient with symptoms suggestive of a dissociative disorder is presented. The consultant reviews the diagnosis of multiple personality disorder (MPD) as defined in DSM-III-R and DSM-IV in relation to the patient's dissociative states, hallucinations, memory loss, and other symptoms. He then highlights the distinctions among MPD, schizophrenia, borderline personality disorder, major depression, and complex partial seizures. After presenting the conceptualization of MPD as a chronic posttraumatic stress disorder, he concludes with a review of treatment approaches that address the traumatic history and that involve hypnosis to gain access to and control dissociative states.

Spiegel, D. (1992). "The use of hypnosis in the treatment of PTSD." Psychiatr Med 10(4): 21-30.

Roudebush, R. E., P. L. Berry, et al. (1991). "Dissociation of immunosuppression by chlorpromazine and trifluoperazine from pharmacologic activities as dopamine antagonists." Int J Immunopharmacol 13(7): 961-8.
Neuroleptic compounds may affect the immune system through a variety of mechanisms. Most possess a complex pharmacology, which makes specific, causal relationships difficult to discern. In this study, a series of experiments was performed to examine the effects of dopamine antagonists on a battery of immunologic parameters. Mitogen-induced lymphocyte proliferation in vitro was inhibited by haloperidol, chlorpromazine, and trifluoperazine at 10, 1 and 1 microM concentrations, respectively. Sulpiride and metoclopramide had no direct effect in vitro. In vivo lymphocyte proliferation was significantly reduced by chlorpromazine at the highest tested doses (12.5 and 15 mg/kg) and by trifluoperazine at the highest tested dose (30 mg/kg). All other dopamine antagonists had no significant effect on in vivo lymphocyte proliferation. A murine graft vs host (GVH) response was unaffected by haloperidol, sulpiride, and metoclopramide. Chlorpromazine and trifluoperazine exhibited significant inhibition of the GVH response at the highest doses only (15 and 30 mg/kg, respectively). In a picryl chloride induced delayed type hypersensitivity (DTH) assay, haloperidol, metoclopramide, and sulpiride had no effect. However, both chlorpromazine and trifluoperazine significantly reduced DTH-induced paw swelling at the higher doses (7.5 mg/kg, and 10 and 30 micrograms/kg, respectively). These studies indicate that the more specific dopamine antagonists (e.g. sulpiride, metoclopramide, and haloperidol) do not share the immunologic profiles of chlorpromazine and trifluoperazine, suggesting that these effects of chlorpromazine and trifluoperazine are not related to their dopamine antagonist properties.

Spiegel, D. (1991). "Neurophysiological correlates of hypnosis and dissociation." J Neuropsychiatry Clin Neurosci 3(4): 440-5.

Spiegel, D. and E. Cardena (1991). "Disintegrated experience: the dissociative disorders revisited." J Abnorm Psychol 100(3): 366-78.
We present proposed changes to the dissociative disorders section of the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders and review the concept of pathological and nonpathological dissociation, including empirical findings on the relations between trauma and dissociative phenomenology and between dissociation and hypnosis. The most important proposals include the creation of two new diagnostic entities, brief reactive dissociative disorder and transient dissociative disturbance, and the readoption of the criterion of amnesia for a multiple personality disorder diagnosis. We conclude that further work on dissociative processes will provide an important link between clinical and experimental approaches to human cognition, emotion, and personality.

Spiegel, D. and F. Cardena (1991). "Comments on hypnotizability and dissociation." Am J Psychiatry 148(6): 813-5.

Spiegel, D. and E. Cardena (1990). "New uses of hypnosis in the treatment of posttraumatic stress disorder." J Clin Psychiatry 51 Suppl: 39-43; discussion 44-6.
Hypnosis is associated with the treatment of posttraumatic stress disorder (PTSD) for two reasons: (1) the similarity between hypnotic phenomena and the symptoms of PTSD, and (2) the utility of hypnosis as a tool in treatment. Physical trauma produces a sudden discontinuity in cognitive and emotional experience that often persists after the trauma is over. This results in symptoms such as psychogenic amnesia, intrusive reliving of the event as if it were recurring, numbing of responsiveness, and hypersensitivity to stimuli. Two studies have shown that Vietnam veterans with PTSD have higher than normal hypnotizability scores on standardized tests. Likewise, a history of physical abuse in childhood has been shown to be strongly associated with dissociative symptoms later in life. Furthermore, dissociative symptoms during and soon after traumatic experience predict later PTSD. Formal hypnotic procedures are especially helpful because this population is highly hypnotizable. Hypnosis provides controlled access to memories that may otherwise be kept out of consciousness. New uses of hypnosis in the psychotherapy of PTSD victims involve coupling access to the dissociated traumatic memories with positive restructuring of those memories. Hypnosis can be used to help patients face and bear a traumatic experience by embedding it in a new context, acknowledging helplessness during the event, and yet linking that experience with remoralizing memories such as efforts at self-protection, shared affection with friends who were killed, or the ability to control the environment at other times. In this way, hypnosis can be used to provide controlled access to memories that are then placed into a broader perspective. Patients can be taught self-hypnosis techniques that allow them to work through traumatic memories and thereby reduce spontaneous unbidden intrusive recollections.

Spiegel, D. (1989). "Hypnosis in the treatment of victims of sexual abuse." Psychiatr Clin North Am 12(2): 295-305.
The relevance of hypnosis to the treatment of sexual assault derives from two sources: the fact that hypnotic phenomena are mobilized spontaneously as defenses during assault, becoming part of the syndrome of posttraumatic stress disorder (PTSD) and the usefulness of formal hypnosis in treating PTSD. The role of dissociative defenses during and after traumatic experiences is reviewed; an analogy between the major elements of formally-induced hypnosis--absorption, dissociation, and suggestibility, and the major elements of PTSD--is drawn. Special problems relevant to sexual assault in childhood are discussed, including extreme self-blame and a profound sense of personality fragmentation. Uses of hypnosis in the treatment of sexual assault victims are reviewed, with an emphasis on helping such patients restructure their memories of the experience, both by reviewing them with greater control over their physical sense of comfort and safety and by balancing painful memories with recognition of their efforts to protect themselves or someone else who was endangered. The use of a split-screen technique in hypnosis is described with a clinical example. Special considerations in such treatment, including the traumatic transference and forensic complications of such psychotherapeutic work, are enumerated.

Spiegel, D. (1988). "Commentary. The treatment accorded those who treat patients with multiple personality disorder." J Nerv Ment Dis 176(9): 535-6.

Spiegel, D., T. Hunt, et al. (1988). "Dissociation and hypnotizability in posttraumatic stress disorder." Am J Psychiatry 145(3): 301-5.
The authors compared the hypnotizability of 65 Vietnam veteran patients with posttraumatic stress disorder (PTSD) to that of a normal control group and four patient samples using the Hypnotic Induction Profile. The patients with PTSD had significantly higher hypnotizability scores than patients with diagnoses of schizophrenia (N = 23); major depression, bipolar disorder--depressed, and dysthymic disorder (N = 56); and generalized anxiety disorder (N = 18) and the control sample (N = 83). This finding supports the hypothesis that dissociative phenomena are mobilized as defenses both during and after traumatic experiences. The literature suggests that spontaneous dissociation, imagery, and hypnotizability are important components of PTSD symptoms.

Frances, A. and D. Spiegel (1987). "Chronic pain masks depression, multiple personality disorder." Hosp Community Psychiatry 38(9): 933-5.

Spiegel, D. (1986). "Dissociating damage." Am J Clin Hypn 29(2): 123-31.

Miller, S. D. and L. D. Butler (1984). "T-cell responses induced by the parenteral injection of antigen-modified syngeneic cells. III. Dissociation of primed cytolytic T-cell and efferent suppressor-T-cell activity following intravenous injection of trinitrophenol-modified syngeneic spleen cells." Cell Immunol 86(2): 308-16.
The parenteral injection of ligand-coupled syngeneic spleen cells has profound effects on immune responsiveness. In this regard, it was examined whether the primed in vitro trinitrophenol (TNP)-specific cytotoxic T-lymphocyte (CTL) responses observed in splenic T-cell populations from mice injected intravenously (iv) with syngeneic TNP-modified spleen cells (TNP-SC) are related to the efferent-acting suppressor-T-cell (Ts) activity observed in splenocytes from iv primed mice. Treatment of mice with cyclophosphamide, adult thymectomy, or monoclonal anti-I-J antiserum prior to the iv injection of TNP-SC was found to eliminate the ability of splenic Ts from these mice to suppress the passive transfer of delayed-type hypersensitivity (DTH) mediated by trinitrochlorobenzene-immune T cells. In contrast, spleen cells from these pretreated mice showed no impairment in the development of augmented TNP-specific CTL responses upon in vitro restimulation with TNP-SC. Separation of the two activities was also achieved in a kinetic analysis. It is concluded that specific enhancement of CTL responsiveness induced by the iv injection of TNP-SC is related to the expansion of a population prelytic Lyt 2+ CTL effector cells which does not appear to contain efferent-acting Lyt 2+ Ts active in suppressing DTH expression.

Spiegel, D. (1984). "Multiple personality as a post-traumatic stress disorder." Psychiatr Clin North Am 7(1): 101-10.
This article examines multiple or dissociative personality syndrome as a multiple post-traumatic stress disorder, discussing these patient's developmental histories, their high hypnotizability, and their profound capacity to dissociate spontaneously to protect themselves from emotional and physical pain.

Spiegel, D. and A. Rosenfeld (1984). "Spontaneous hypnotic age regression: case report." J Clin Psychiatry 45(12): 522-4.
Age regression--reliving the past as though it were occurring in the present, with age appropriate vocabulary, mental content, and affect--can occur with instruction in highly hypnotizable individuals, but has rarely been reported to occur spontaneously, especially as a primary symptom. The psychiatric presentation and treatment of a 16-year-old girl with spontaneous age regressions accessible and controllable with hypnosis and psychotherapy are described. Areas of overlap and divergence between this patient's symptoms and those found in patients with hysterical fugue and multiple personality syndrome are also discussed.

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