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Dissociation and posttraumatic stress 1 year after the World Trade Center disaster: follow-up of a longitudinal survey.

BACKGROUND: We conducted a 1-year follow-up of an original mail survey of early reactions to the World Trade Center disaster. METHOD: Of the 75 subjects originally surveyed, 58 (77%) responded. The survey included measures of dissociation (Dissociative Experiences Scale, Cambridge Depersonalization Scale, Clinician-Administered Dissociative States Scale), post-traumatic stress (Impact of Event Scale-Revised), social support (Interpersonal Support Evaluation List-short form), and a life quality measure (Quality of Life Enjoyment and Satisfaction Questionnaire-short form). We hypothesized that dissociative versus posttraumatic symptoms at follow-up could be dissected on the basis of early reactions. RESULTS: Responders and nonresponders did not differ in baseline characteristics. Exposure was not associated with dissociation or posttraumatic stress at follow-up. Of distress, dissociation, and posttraumatic stress at baseline, baseline dissociation was the strongest predictor of outcome dissociation while baseline posttraumatic stress was the strongest predictor of outcome posttraumatic stress. Of 4 peritraumatic distress factors generated in the original survey, "loss of control" and "guilt/shame" were significantly related to dissociation and posttraumatic stress at outcome, while "helplessness/anger" was only associated with posttraumatic stress at outcome. Lesser improvement in posttraumatic stress over the first year was significantly related to less social support and greater comorbid dissociation. Interim social support was associated with better life quality and fewer symptoms at outcome. CONCLUSION: There was evidence for partly independent pathways toward dissociation versus posttraumatic stress 1 year after the disaster. Feelings of guilt and shame, and persistent dissociation, were poor prognostic factors, while social support had a powerful ameliorating influence.

Adult↗

Prevalence of dissociative symptoms and disorders in an adult psychiatric inpatient population in Canada.

OBJECTIVE: This study attempted to estimate the prevalence of dissociative symptoms and disorders in a Canadian adult psychiatric inpatient population and also attempted to determine the extent to which dissociative disorders were recognized by the attending clinical staff. METHOD: All appropriate and consenting adult psychiatric inpatients at the Kingston Psychiatric Hospital in Kingston, Ontario, were given the Dissociative Experiences Scale. Patients scoring 25 or greater were interviewed with the Dissociative Disorders Interview Schedule and the Structured Clinical Interview for DSM-IV Dissociative Disorders. Admission or discharge diagnoses data were used to determine whether or not dissociative disorders were being recognized. RESULTS: A total of 48 patients completed the Dissociative Experiences Scale and 14 (29%) scored 25 or greater. The prevalence of dissociative disorders in this hospital population was estimated to be 17%. Dissociative identity disorder was found in six percent, dissociative amnesia in eight percent and dissociative disorder not otherwise specified in two percent of the population. These disorders tended to be under-recognized. CONCLUSION: Research on more extensive populations is required to establish the true prevalence of dissociative symptoms and disorders in psychiatric inpatients.

Adult↗

High density sickle cell erythrocyte core membrane skeletons demonstrate slow temperature dependent dissociation.

We have previously demonstrated that slow dissociation of HDSS membrane skeletons in high ionic strength Triton X-100 buffer was related to a posttranslational modification in beta-actin, in which a disulfide bridge was formed between cysteine 284 and cysteine 373[Shartava et al: J Cell Bio 128:805, 1995]. These previous dissociation assays were limited to two homozygous (SS) sickle cell patients and a single temperature (37 degrees C). In the current work, we have expanded the SS subjects to 9 and have carried out dissociation assays at 0, 24, 30, 34, and 37 degrees C. At 0 degrees C there was limited dissociation of spectrin and actin from normal(AA), low density sickle cell(LDSS), and high density sickle cell (HDSS) core skeleton up to 24 hr. The first order rate constants for dissociation of spectrin, at 0 degrees C, was 0.030-0.035 x 10-4 sec-1 for AA,LDSS, and HDSS core skeletons. However at 24, 30, 34, and 37 degrees C the rate of dissociation of spectrin from HDSS core skeletons was significantly slower than the rate of dissociation from AA core skeletons. Having determined the first order rate constants for spectrin dissociation at these specified temperatures, we then asked whether dithiothreitol (DTT) would hasten the dissociation of core skeletons. The presence of DTT caused the rate of dissociation of the HDSS membrane skeleton to become statistically indistinguishable from the rate of dissociation of AA membrane skeletons. This is consistent with the suggestion that reversible thiol oxidation is responsible for the slow dissociation of the HDSS membrane skeleton.

Actins↗

Dissociation of peripheral protein-membrane complexes by high pressure.

The ability of high pressure to dissociate several peripheral protein-membrane complexes was investigated. Three vitamin K-dependent proteins (factor X, protein Z, and prothrombin) dissociated from small unilamellar vesicles (SUVs, 30 nm diameter) composed of 25% phosphatidylserine (PS) and 75% phosphatidylcholine (PC) at comparable pressures (midpoints of 0.3-0.6 kbar). The pressure-induced dissociation curves for the factor X-SUV interaction followed the expected behavior for an interaction with an apparent dissociation equilibrium constant at atmospheric pressure, KD(atm), of 9 x 10(-7) M and a change in volume of association, delta Va, of 88 mL/mol. Factor X also dissociated from large unilamellar vesicles (LUVs, 100 nm diameter, 25% PS:75% PC) with a midpoint of 0.5 kbar. A second group of calcium-dependent membrane-binding proteins included protein kinase C (PKC), a 64-kDa protein, and a 32-kDa protein. The 32-kDa protein dissociated from SUVs (midpoint of 0.8 kbar), whereas PKC and the 64-kDa protein did not dissociate to a significant degree. The differences in dissociability of these proteins appeared to be a result of the differences in their KD(atm)'s (decreased dissociability with decreased KD(atm)). This pattern was further demonstrated by the relatively high midpoint of dissociation (1.1-1.4 kbar) of serum amyloid P component (SAP; KD(atm) ca. 10(-11)) and the limited dissociation of factor Va light chain (KD(atm) ca. 10(-11)). Changing the vesicle composition to phosphatidylethanolamine in place of PC gave higher affinity and decreased dissociation of the 32-kDa protein and SAP.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗

Photoinduced dissociation of electrospray-generated ions in an ion trap/time-of-flight mass spectrometer using a pulsed CO2 laser.

An ion trap/time-of-flight (IT/TOF) mass spectrometer was developed and applied to infrared multiphoton dissociation (IRMPD) studies of ions generated by electrospray ionization. A pulsed 10.6- micro m laser beam from a CO(2) laser was used for excitation of trapped ions. Results from IRMPD of peptide ions show that this method provides useful information related to the amino acid sequence of analyzed peptides. Comparative studies show that IRMPD spectra are similar to those obtained using a 266-nm UV laser beam for excitation. However, in contrast to multiple-pulse excitation required at 266 nm, the energy of a single laser pulse in IRMPD is sufficient to induce dissociation of peptide ions. The laser power is practically an exclusive parameter that must be controlled in order to obtain IRMPD spectra that will provide the optimal structural information. It is further demonstrated that the IRMPD IT/TOF technique has the potential to probe the structural features of larger ions that cannot be readily fragmented by collision-induced dissociation (CID). A multiply charged ion of equine cytochrome c is successfully fragmented in a single laser pulse experiment. The IRMPD IT/TOF technique is also shown to be a promising tool for studying dissociation kinetics of peptide and protein ions. Unlike other methods that usually monitor the dissociation ion kinetics in a dissociation time frame of greater than milliseconds, the IT/TOF can promptly detect all product ions generated by the dissociation process, and thus monitor the dissociation process of peptides and proteins in a sub-millisecond time frame. This instrument allows us to determine the dissociation rates of cytochrome c ions using high-energy photoexcitation. It is found that the charge state of the protein ion has a significant effect on dissociation kinetics, which is consistent with that found under low-energy excitation experiments. It is shown that the increase in energy of a laser pulse from 130 to 180 mJ changes the dissociation rate constant for the +12 ion from k = 2.4 x 10(3) x s(-1) to k = 7.3 x 10(4) x s(-1). The +8 ion following excitation at 130 mJ dissociates slower with a rate constant of k = 2.6 x 10(2) x s(-1). The rate difference observed is attributed to conformational differences among the ions with different charge states.

Journal Article↗

Estrogen receptor in chicken oviduct: receptor dissociation kinetics and transformation.

Cytosolic and nuclear estrogen receptor forms of chicken oviduct have been studied by (1) measuring hormone dissociation kinetics and by (2) sucrose density gradient analysis on high salt gradients. Estradiol dissociates from the receptor in chicken oviduct cytosol at 22 degrees C following a two-phase exponential process. The fraction of receptor with a fast dissociation rate (k = 120 X 10(-3) min-1) decreases as a function of the pre-incubation at 22 degrees C; after prolonged pre-incubation only the slowly dissociating (k = 12.3 X 10(-3) min-1) form remains. Dissociation of moxestrol, a synthetic estrogen with a higher affinity, from the cytosol receptor at 30 degrees C is similar, showing a transition of a fast dissociating form (k = 120 X 10(-3) min-1) to a slowly dissociating form (k = 7.6 X 10(-3) min-1) as a result of pre-incubation at 30 degrees C. A concomitant temperature-dependent shift of the estrogen receptor from a 4.8 S to a 6.1 S form was observed with moxestrol but not with estradiol as a ligand. Sodium molybdate (20 mM) and NaSCN (400 mM) inhibit the temperature-dependent increase in sedimentation coefficient, but molybdate allows the formation of a receptor form which shows intermediary dissociation kinetics. Estrogen receptor, precipitated with ammonium sulfate (0-35%) shows monophasic dissociation kinetics of estradiol (k = 39.5 X 10(-3) min-1) and for moxestrol (k = 10.8 X 10(-3) min-1), suggesting full receptor activation only with moxestrol as a ligand. Moxestrol-receptor complexes obtained by ammonium sulfate precipitation sediment at 0 degree C at 4.8 S. Only after subsequent incubation at 30 degrees C a shift from 4.8 S to 5.9 S is observed, suggesting that the formation of the slowly dissociating form of the receptor may precede the formation of a stable transformed receptor complex. The nuclear estrogen receptor with estradiol as a ligand shows biphasic dissociation kinetics at 22 degrees C (k = 70 X 10(-3) min-1; k = 14.0 X 10(-3) min-1). The ratio of both components (1:1) does not change after preincubation of the nuclear receptor extract at 22 degrees C. Moxestrol dissociates from the nuclear receptor at 30 degrees C monophasically with a slow rate (k = 6.1 X 10(-3) min-1), suggesting that it is extracted as an activated hormone-receptor complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Kinetics of ribosome dissociation and subunit association studied in a light-scattering stopped-flow apparatus.

The association-dissociation kinetics of ribosomes from Escherichia coli have been studied under various conditions in a light-scattering stopped-flow apparatus. The dissociation reaction at 2 mg/ml at 25 degrees C, induced by lowering the MgCl2 concentration from 18 to 3 mM, can best be described by three independent first-order processes with rate constants of 15 s-1, 0.9 s-u, and 3 X 10(-2) s-1, the slowest process comprising about 60% of the overall reaction. The fraction of ribosomes dissociating with the fastest rate (15 s-1) is concentration dependent and becomes negligible at 0.1 mg/ml9 Ribosomes treated with puromycin also show three dissociation rates with essentially the same rate constants as the nontreated samples. The dissociation induced by a high KCl concentration (0.85 MKCl, 18 mM MgCl) also shows three first-order phases with the same rate constants as for the dissociation induced by lowering the MgCl2 concentration. The formation of 70S ribosomes from 30S and 50S subunits, induced by increasing the MgCl2 concentration from 2 to 21 mM, follows second-order biphasic kinetics. A detailed analysis of the kinetic results shows that the two principal ribosomal forms must have one type of subunit in common. When the association data are analyzed assuming that the kinetic heterogeneity arises from two forms of only one subunit, the rate constants are found to be 6.4 X 10(6) and 1.05 X 10(6) M-1 s-1. Sequential flow experiments show that the rapid and slow association species are to be identified, respectively, with phases II (0.9 s-1) and III 0.03 s-1) of dissociation. Relaxation measurements show that these correspond to type B ("loose") and A ("tight") ribosomes, respectively. Tight and loose ribosomes were isolated by sucrose density centrifugation, and dissociation and association kinetic studies confirmed the above assignments. Furthermore, the rate constants for these ribosoems agreed within experimental error with rate constants derived from analysis of the multiphasic kinetic data. The association rate constants are for ribosomes dissociated by dilution with the appropriate buffer immediately before recording the kinetics of association. Ribosomes dissociated by dialysis overnight against 2 mM MgCl2 show an association rate constant for the slower association reaction (type-A ribosome) that is about four times smaller, whereas the rate constant for the faster process is roughly the same. The activation energies of the dissociation reactions, whether induced by lowering the MgCl2 concentration or increasing the KCl concentration, and the association raaction induced by increasing the MgCl2 concentration are less than 3.5 kcal/mol. The rate constants of the dissociation at 3 mM MgCl2 and of the association reaction at 21 mM MgCl2 do not vary between pH 7.2 and 8.4. When 30S and 50S subunits are flowed against buffer containing 20 mM spermidine, the association process is monophasic, with an association constant k - 6 X 10(6) M-1 s-1...

Binding Sites↗

Dissociation of ribulose-1,5-bisphosphate carboxylase/oxygenase from spinach by urea.

The dissociation of D-ribulose-1,5-bisphosphate carboxylase/oxygenase from spinach, which consists of eight large subunits (L, 53 kDa) and eight small subunits (S, 14 kDa) and thus has a quarternary structure L8S8, has been investigated using a variety of physical techniques. Gel chromatography using Sephadex G-100 indicates the quantitative dissociation of the small subunit S from the complex at 3-4 M urea (50 mM Tris/Cl pH 8.0, 0.5 mM EDTA, 1 mM dithiothreitol and 5 mM 2-mercaptoethanol). The dissociated S is monomeric. Analytical ultracentrifuge studies show that the core of large subunits, L, remaining at 3-4 M urea sediments with S20, w = 15.0 S, whereas the intact enzyme (L8S8) sediments with S20, w = 17.7S. The observed value is consistent with a quarternary structure L8. The dissociation reaction in 3-4 M urea can thus be represented by L8S8----L8 + 8S. At urea concentrations c greater than 5 M the L8 core dissociates into monomeric, unfolded large subunits. A large decrease in fluorescence emission intensity accompanies the dissociation of the small subunit S. This change is completed at 4 M urea. No changes are observed upon dissociating the L8 core. The kinetics of dissociation of the small subunit, as monitored by fluorescence spectroscopy, closely follow the kinetics of loss of carboxylase activity of the enzyme. Studies of the circular dichroism of D-ribulose-1,5-bisphosphate carboxylase in the wavelength region 200-260 nm indicate two conformational transitions. The first one ([0]220 from -8000 to -3500 deg cm2 dmol-1) is completed at 4 M urea and corresponds to the dissociation of the small subunit and coupled conformational changes. The second one ([0]220 from -3500 to -1200 deg cm2 dmol-1) is completed at 6 M urea and reflects the dissociation and unfolding of large subunits from the core. The effect of activation of the enzyme by addition of MgCl2 (10 mM) and NaHCO3 (10 mM) on these conformational transitions was investigated. The first conformational transition is then shifted to higher urea concentrations: a single transition ([0]220 from -8000 to -1200 deg cm2 dmol-1) is observed for the activated enzyme. From the urea dissociation experiments we conclude that both large (L) and small (S) subunits are important for carboxylase activity of spinach D-ribulose-1,5-bisphosphate carboxylase: the L-S subunit interactions tighten upon activation and dissociation of S leads to a coupled, proportional loss of enzyme activity.

Chemical Phenomena↗

Trauma and dissociation in China.

OBJECTIVE: In order to determine whether pathological dissociation occurs in China, the authors conducted a survey among psychiatric inpatients, outpatients, and the general population in Shanghai, China. There is virtually no popular or professional knowledge of dissociative identity disorder in China, and therefore professional and popular contamination cannot exist. METHOD: Chinese versions of the Dissociative Experiences Scale and the Dissociative Disorders Interview Schedule were administered to 423 inpatients, 304 outpatients, and 618 factory workers in Shanghai by Chinese psychiatrists working at the Shanghai Mental Health Center. RESULTS: Dissociative disorders were diagnosed in 24 respondents by structured interview, and 15 respondents fell into the dissociative taxon on the Dissociative Experiences Scale. The outpatients reported the highest rates of childhood physical and/or sexual abuse and of pathological dissociation. CONCLUSIONS: Pathological dissociation can be detected readily among psychiatric outpatients in China but is much less common in the general population. Pathological dissociation is more frequent in more traumatized subsamples of the Chinese population. The findings are not consistent with the sociocognitive, contamination, or iatrogenic models of dissociative identity disorder.

Adult↗

Dissociation and symptom dimensions of obsessive-compulsive disorder. A replication study.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a phenotypically very heterogeneous disease with high rates of comorbid psychiatric pathology. Previous studies have indicated that OCD is associated with higher levels of dissociation. The aims of the present study were to replicate and extend previous findings of a significant link between certain OCD symptom dimensions and dissociation. METHODS: The study sample comprised 50 patients with OCD, as confirmed by the Mini International Neuropsychiatric Interview,who had a score of at least 16 on the Yale-Brown Obsessive-Compulsive Scale. All patients were assessed with the short version of the Hamburg Obsessive-Compulsive Inventory and the Dissociative Experience Scale (DES). Correlation analyses and multiple regression analyses were performed to evaluate the relationship between OCD symptom dimensions and dissociation. RESULTS: The checking dimension was most strongly related to dissociation, followed by the symmetry/ordering and obsessive thoughts dimensions. In contrast, no significant relationship was found between dissociation and the washing/cleaning, counting/touching, and aggressive impulses/fantasies dimensions. Multiple regression analyses revealed that: (1) only the checking dimension showed an independent positive correlation with dissociation, and (2) only higher scores on the DES subscale "amnestic dissociation" were associated with higher scores for checking compulsions. CONCLUSIONS: Our results suggest that there might be a specific link between checking behavior and dissociation in OCD. Moreover, checking compulsions seem to be particularly associated with amnestic dissociation. Further studies focusing on amnestic dissociation as a potentially important determinant of checking compulsions are warranted.

Adult↗

Dissociative disorders in the psychiatric emergency ward.

OBJECTIVE: The aim of this study was to determine the prevalence of dissociative disorders among emergency psychiatric admissions. METHOD: Forty-three of the 97 consecutive outpatients admitted to the psychiatric emergency unit of a university hospital were screened using the Dissociative Experiences Scale (DES). Seventeen (39.5% of the 43 evaluated) patients with a DES score above 25.0 were then interviewed with the Dissociative Disorders Interview Schedule and the Structured Clinical Interview for Dissociative Disorders. RESULTS: Fifteen emergency unit patients (34.9% of the 43 evaluated participants) were diagnosed as having a dissociative disorder. Six (14.0%) patients had dissociative identity disorder, 6 (14.0%) had dissociative disorder not otherwise specified, and 3 (7.0%) had dissociative amnesia. The average DES score of dissociative patients was 43.7. A majority of them had comorbid major depression, somatization disorder, and borderline personality disorder. Most of the patients with dissociative disorder reported auditory hallucinations, symptoms associated with psychogenic amnesia, flashback experiences, and childhood abuse and/or neglect. CONCLUSIONS: Dissociative disorders constitute one of the diagnostic groups with high relevance in emergency psychiatry.

Adolescent↗

Prevalence of dissociative disorders among women in the general population.

This study sought to determine the prevalence of dissociative disorders among women in the general population, as assessed in a representative sample of a city in central Turkey. The Dissociative Disorders Interview Schedule (DDIS), the Borderline Personality Disorder section of the Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II), and the PTSD-Module of the Structured Clinical Interview for DSM-III-R (SCID) were administered to 628 women in 500 homes. The mean age of participants was 34.8 (S.D.=11.5, range: 18-65); 18.3% of participants (n=115) had a lifetime diagnosis of a dissociative disorder. Dissociative disorder not otherwise specified (DDNOS) was the most prevalent diagnosis (8.3%); 1.1% of the population was diagnosed as having dissociative identity disorder (DID). Participants with a dissociative disorder had borderline personality disorder, somatization disorder, major depression, PTSD, and history of suicide attempt more frequently than did participants without a dissociative disorder. Childhood sexual abuse, physical neglect, and emotional abuse were significant predictors of a dissociative disorder diagnosis. Only 28.7% of the dissociative participants had received psychiatric treatment previously. Because dissociative disorders are trauma-related, significant part of the adult clinical consequences of childhood trauma remains obscure in the minds of mental health professionals and of the overall community. Revisions in diagnostic criteria of dissociative disorders in the DSM-IV are recommended.

Adolescent↗

Peritraumatic versus persistent dissociation in acute stress disorder.

The DSM-IV definition of acute stress disorder (ASD) regards dissociation that occurs during a trauma (peritraumatic dissociation) comparably to persistent dissociation. This study investigated the relative contributions of peritraumatic dissociation and persistent dissociation to acute posttraumatic stress reactions. Civilian trauma (N = 53) survivors with either acute stress disorder (ASD), subclinical ASD, or no ASD were administered modified versions of the Peritraumatic Dissociative Experiences Questionnaire that indexed both dissociation during the trauma and dissociation at the time of assessment. Persistent dissociation was more strongly associated with ASD severity and intrusive symptoms than peritraumatic dissociation. These results are consistent with the proposition that persistent, rather than peritraumatic, dissociation is associated with posttraumatic psychopathology.

Adult↗

Trauma and dissociation in treatment-seeking alcoholics: towards a resolution of inconsistent findings.

There is consistent empirical evidence for a trauma-dissociation relation in general population samples and in psychiatric patients. However, contradictory findings have been reported on this relation among substance abusers. The present study attempts to resolve these inconsistencies by testing a series of hypotheses related to problems regarding the measurement of childhood abuse, the measurement of psychological dissociation, and the potential existence of substance abuse as a form of chemical dissociation. Alcoholic patients (N = 155) were administered the Dissociative Experiences Scale (DES), the Structured Trauma Interview (STI), the European Addiction Severity Index (EuropASI), and the Posttraumatic Stress Disorder (PTSD) section of the Composite International Diagnostic Interview (CIDI). The DES showed good psychometric properties. Substantial rates of traumatization and PTSD were observed, as well as a significant trauma-PTSD relation. However, the mean DES score was low (11.4) and dissociation was not related to trauma (childhood or lifetime) or to PTSD. Years of lifetime regular medicine use, however, was significantly correlated with the severity of dissociative symptoms and PTSD, particularly in males. Overall, these findings suggest that absence of a trauma-dissociation relation in alcoholics may not be due to measurement problems of childhood abuse and/or dissociation. Rather, a trauma-dissociation link may not exist, particularly in male alcoholics, because these individuals may abuse substances to achieve dissociative-like states. Additional research is needed to further evaluate the utility of the DES in alcoholic samples and to examine the notion of chemical dissociation.

Adult↗

Dissociative symptoms and trauma exposure: specificity, affect dysregulation, and posttraumatic stress.

Although dissociation is often described as a posttraumatic response, the actual statistical association between trauma exposure and dissociative symptoms is surprisingly small. This suggests that that some dissociative phenomena may be unrelated to trauma, or may be related in more complex ways. Analysis of the normative data for the Multiscale Dissociation Inventory revealed significant dissociative symptoms in only 8% of trauma-exposed individuals from the general population. However, 90% of those with at least one clinically significant dissociation scale on the Multiscale Dissociation Inventory reported a trauma history, and significant dissociation was found in only 2% of nontraumatized individuals. A history of interpersonal violence, number of different types of trauma exposure, posttraumatic stress, and affect dysregulation were univariate predictors of dissociative symptomatology in trauma-exposed participants, but only posttraumatic stress and affect dysregulation were multivariate predictors. Trauma is probably an important, but insufficient, condition for the development of dissociative symptomatology. Additional risk factors, such as high posttraumatic stress and/or reduced affect regulation capacities, may determine whether trauma exposure results in clinically significant dissociation.

Adolescent↗

Exploring the relations between depression, somatization, dissociation and alexithymia--overlapping or independent constructs?

BACKGROUND: The aim of this study was to extend our knowledge of associations among the constructs of alexithymia, depression, somatization and dissociation. SAMPLING AND METHODS: 924 nonclinical subjects answered questions about depression (21-item Beck Depression Inventory), somatization (13-item somatization part of Symptom Check List-90), dissociation (28-item Dissociative Experiences Scale) and alexithymia (20-item Toronto Alexithymia Scale). In addition, a 12-item General Health Questionnaire (GHQ-12) was administered to detect psychiatric distress among subjects. RESULTS: The results suggested that there was a significant clinical correlation between somatization, dissociation, depression and alexithymia (rho varied from 0.31 to 0.56). The principal component analysis revealed the presence of four components: depression, somatization, dissociation and alexithymia. The use of factor scores diminished the covariance between measures (rho varied from -0.10 to 0.01 between the factor scores). There was almost no correlation between the dissociation factor (rho = 0.06) and alexithymia factor (rho = 0.09) scores and general distress (GHQ-12). CONCLUSIONS: This study suggests that while somatization, dissociation, depression and alexithymia are distinct constructs, they correlate to a considerable extent. The use of factor analysis and factor scores should be considered to diminish covariance between the above constructs. Comparing results between factored and unfactored results may prove illuminating. As a case in point, the results suggest that the part of dissociation that coincides with other constructs (overlaps) is associated with distress, whereas the distinct part of dissociation (no shared covariance) is not associated with distress. The same applies to the alexithymia construct. Longitudinal studies are needed to show whether there is a trait such as a relatively stable dissociation component and also whether a separate state-dependent dissociation component exists that is associated with coincident distress, somatization and depression.

Adolescent↗

Dissociation and posttraumatic stress disorder in Vietnam combat veterans.

OBJECTIVE: This study compared current dissociative symptoms and dissociation at the time of specific traumatic events in Vietnam combat veterans with posttraumatic stress disorder (PTSD) and Vietnam combat veterans without PTSD. METHOD: Vietnam combat veterans who sought treatment for PTSD (N = 53) were compared to Vietnam combat veterans without PTSD (N = 32) who sought treatment for medical problems. Dissociative symptoms were evaluated with the Dissociative Experiences Scale. Dissociation at the time of a combat-related traumatic event was evaluated retrospectively with the modified Dissociative Experiences Questionnaire. The Combat Exposure Scale was used to measure level of combat exposure. RESULTS: There was a significantly higher level of dissociative symptoms, as measured by the Dissociative Experiences Scale, in patients with PTSD (mean = 27.0, SD = 18.0) than in patients without PTSD (mean = 13.7, SD = 16.0). This difference persisted when the difference in level of combat exposure was controlled with analysis of covariance. PTSD patients also reported more dissociative symptoms at the time of combat trauma, as measured retrospectively by the Dissociative Experiences Questionnaire (mean = 11.5, SD = 1.6) than non-PTSD patients (mean = 1.8, SD = 2.1). CONCLUSIONS: Dissociative symptoms are an important element of the long-term psychopathological response to trauma.

Adult↗

Peritraumatic dissociation and posttraumatic stress in male Vietnam theater veterans.

OBJECTIVE: The aim of this study was to determine the reliability and validity of a proposed measure of peritraumatic dissociation and, as part of that effort, to determine the relationship between dissociative experiences during disturbing combat trauma and the subsequent development of posttraumatic stress disorder (PTSD). METHOD: A total of 251 male Vietnam theater veterans from the Clinical Examination Component of the National Vietnam Veterans Readjustment Study were examined to determine the relationship of war zone stress exposure, retrospective reports of dissociation during the most disturbing combat trauma events, and general dissociative tendencies with PTSD case determination. RESULTS: The total score on the Peritraumatic Dissociation Experiences Questionnaire--Rater Version was strongly associated with level of posttraumatic stress symptoms, level of stress exposure, and general dissociative tendencies and weakly associated with general psychopathology scales from the MMPI-2. Logistic regression analyses supported the incremental value of dissociation during trauma, over and above the contributions of level of war zone stress exposure and general dissociative tendencies, in accounting for PTSD case determination. CONCLUSIONS: These results provide support for the reliability and validity of the Peritraumatic Dissociation Experiences Questionnaire--Rater Version and for a trauma-dissociation linkage hypothesis: the greater the dissociation during traumatic stress exposure, the greater the likelihood of meeting criteria for current PTSD.

Adult↗