Biomedical subjects

Peter Roy-Byrne

Publications and source records attributed to Peter Roy-Byrne.

At least 19 recordsLinked to original sources

PubMed2007

Does occasional cannabis use impact anxiety and depression treatment outcomes?: Results from a randomized effectiveness trial.

This study investigated the extent to which occasional cannabis use moderated anxiety and depression outcomes in the Collaborative Care for Anxiety and Panic (CCAP) study, a combined cognitive-behavioral therapy (CBT) and pharmacotherapy randomized effectiveness trial. Participants were 232 adults from six university-based primary care outpatient clinics in three West Coast cities randomized to receive either the CCAP intervention or the usual care condition. Results showed significant (P<.01) evidence of an interaction between treatment group (CCAP vs. usual care) and cannabis use status (monthly vs. less than monthly) for depressive symptoms, but not for panic disorder or social phobia symptoms (all P>.05). Monthly cannabis users' depressive symptoms improved in the CCAP intervention just as much as those who used cannabis less than monthly, whereas monthly users receiving usual care had significantly more depressive symptoms than those using less than monthly. A combined CBT and medication treatment intervention may be a promising approach for the treatment of depression among occasional cannabis users.

Adult↗

PubMed2006

Broadening the definition of generalized anxiety disorder: effects on prevalence and associations with other disorders in the National Comorbidity Survey Replication.

Concerns have been raised that the DSM-IV requirements of 6-month duration, excessive worry, and three associated symptoms exclude a substantial number of people with clinically significant anxiety from a diagnosis of generalized anxiety disorder (GAD). We examined the implications of relaxing these three criteria for the estimated prevalence and predictive validity of GAD using nationally representative data from the US National Comorbidity Survey Replication. Relaxing all three criteria more than doubles the estimated prevalence of GAD. Broadly defined GAD significantly predicts the subsequent first onset of a wide range of temporally secondary disorders. The odds of secondary disorders are somewhat smaller for broadly defined than DSM-IV GAD, though few of these differences are statistically significant. Results suggest that subthreshold manifestations of GAD are significantly related to elevated risk of subsequent psychopathology. Further research is needed to determine whether broadening the current diagnostic criteria results in a more valid characterization of GAD.

Adolescent↗

PubMed2006

CBT intensity and outcome for panic disorder in a primary care setting.

A hybrid efficacy-effectiveness design in which participants (n = 91/93) were retained in the study regardless of whether or not they received treatment enabled evaluation of CBT intensity in relation to panic disorder in the primary care setting. CBT intensity was operationalized as number of cognitive-behavioral therapy sessions, number of follow-up booster phone calls, and secondarily, as number of cognitive behavioral coping and exposure strategies. Baseline psychosocial and demographic predictors of CBT intensity were analyzed first. Severity of anxiety sensitivity predicted number of cognitive behavioral sessions, but no baseline variables predicted number of follow-up booster phone calls or number of coping and exposure strategies. Multivariate logistic and linear regressions were used to evaluate the degree to which treatment intensity predicted 3-month and 12-month outcomes (anxiety sensitivity, phobic avoidance, depressive symptoms, disability, and medical and mental health functioning) after controlling for potential confounding baseline variables. Number of cognitive behavioral therapy sessions predicted lower anxiety sensitivity at 3 and 12 months, and number of follow-up booster phone calls predicted lower anxiety sensitivity, less phobic avoidance, and less depression at 12 months. These findings indicate that "dose" of psychotherapy was an important predictor of outcome. The significance of follow-up booster phone contact is discussed as an index of continued self-management of panic and anxiety following acute treatment.

Adaptation, Psychological↗

PubMed2006

Incremental cost-effectiveness of a collaborative care intervention for panic disorder.

BACKGROUND: Panic disorder is a prevalent, often disabling, disorder among primary-care patients, but there are large gaps in quality of treatment in primary care. This study describes the incremental cost-effectiveness of a combined cognitive behavioral therapy (CBT) and pharmacotherapy intervention for patients with panic disorder versus usual primary-care treatment. METHOD: This randomized control trial recruited 232 primary-care patients meeting DSM-IV criteria for panic disorder from March 2000 to March 2002 from six primary-care clinics from university-affiliated clinics at the University of Washington (Seattle) and University of California (Los Angeles and San Diego). Patients were randomly assigned to receive either treatment as usual or a combined CBT and pharmacotherapy intervention for panic disorder delivered in primary care by a mental health therapist. Intervention patients had up to six sessions of CBT modified for the primary-care setting in the first 12 weeks, and up to six telephone follow-ups over the next 9 months. The primary outcome variables were total out-patient costs, anxiety-free days (AFDs) and quality adjusted life-years (QALYs). RESULTS: Relative to usual care, intervention patients experienced 60.4 [95% confidence interval (CI) 42.9-77.9] more AFDs over a 12-month period. Total incremental out-patient costs were 492 US dollars higher (95% CI 236-747 US dollars ) in intervention versus usual care patients with a cost per additional AFD of 8.40 US dollars (95% CI 2.80-14.0 US dollars ) and a cost per QALY ranging from 14,158 US dollars (95% CI 6,791-21,496 US dollars ) to 24,776 US dollars (95% CI 11,885-37,618 US dollars ). The cost per QALY estimate is well within the range of other commonly accepted medical interventions such as statin use and treatment of hypertension. CONCLUSIONS: The combined CBT and pharmacotherapy intervention was associated with a robust clinical improvement compared to usual care with a moderate increase in ambulatory costs.

Adult↗

PubMed2006

Panic and suicidal ideation and suicide attempts: results from the National Comorbidity Survey.

Our objective was to determine the association between panic attacks (PAs) and panic disorder (PD), and suicidal ideation (SI) and suicide attempts (SAs) in a nationally representative sample of adults in the community. Data were drawn from the National Comorbidity Survey (n=5,877), a representative household sample of adults ages 15-54 in the United States. Multiple logistic regression analyses were used to examine the relationship between current and lifetime PA and PD and SI and SA, adjusting for differences in demographic characteristics, comorbid mental disorders (major depression, alcohol dependence, and substance dependence), childhood trauma (physical and sexual abuse), and number of lifetime mental disorders. Past-year and lifetime PA and PD were associated with increased SI (both past year and lifetime), and persisted after adjusting for comorbidity and early trauma. Associations between PA and SA were no longer statistically significant after adjusting for comorbidity. Past-year and lifetime PD were associated with lifetime SA, but these associations were no longer statistically significant after adjusting for comorbidity. Past-year and lifetime PD were associated with past-year SA, and this association persisted after adjusting for demographics, comorbidity, and number of lifetime mental disorders. These findings are consistent with previous results, and further help to clarify the relationships between panic and suicide behavior by identifying potential methodological reasons for inconsistencies in results from previous studies.

Adolescent↗

PubMed2006

Poverty and response to treatment among panic disorder patients in primary care.

OBJECTIVE: Despite well-established links between poverty and poor mental illness outcome as well as recent reports exploring racial and ethnic health disparities, little is known about the outcomes of evidence-based psychiatric treatment for poor individuals. METHOD: Primary care patients with panic disorder (N=232) who were participating in a randomized controlled trial comparing a cognitive behavior therapy (CBT) and pharmacotherapy intervention to usual care were divided into those patients above (N=152) and below (N=80) the poverty line. Telephone assessments at 3, 6, 9, and 12 months were used to compare the amount of evidence-based care received as well as clinical and functional outcomes. RESULTS: Poor subjects were more severely ill at baseline, with more medical and psychiatric comorbidity. The increases in the amount of evidence-based care and reductions in clinical symptoms and disability were comparable in the two groups such that poorer individuals, although responding equivalently, continued to be more ill and disabled at 12 months. CONCLUSIONS: The comparable response of poor individuals in this study suggests that standard CBT and pharmacotherapy treatments for panic disorder do not need to be "tailored" to be effective in poor populations. However, the more severe illness both at baseline and follow-up in these poor individuals suggests that treatment programs may need to be extended in order to treat residual symptoms and disability in these patients so that they might achieve comparable levels of remission.

Adolescent↗

PubMed2005

A controlled study of repetitive transcranial magnetic stimulation in medication-resistant major depression.

BACKGROUND: Repetitive transcranial magnetic stimulation (TMS) as a treatment for depression has shown statistically significant effects, but the clinical significance of these effects has been questioned. METHODS: Patients with medication-resistant depression were randomized to receive 15 sessions of active or sham repetitive TMS delivered to the left dorsolateral prefrontal cortex at 110% the estimated prefrontal cortex threshold. Each session consisted of 32 trains of 10 Hz repetitive TMS delivered in 5-second trains. The primary end point was treatment response defined as a >or=50% decrease in Hamilton Depression Rating Scale (HDRS) score at both 1 and 2 weeks following the final repetitive TMS treatment. Remission was defined as a HDRS score < 8. RESULTS: The response rate for the TMS group was 30.6% (11/35), significantly (p = .008) greater than the 6.1% (2/33) rate in the sham group. The remission rate for the TMS group was 20% (7/35), significantly (p = .033) greater than the 3% (1/33) rate in the sham group. The HDRS scores showed a significantly (p < .002) greater decrease over time in the TMS group compared with the sham group. CONCLUSIONS: Transcranial magnetic stimulation can produce statistically and clinically significant antidepressant effects in patients with medication-resistant major depression.

Adult↗

PubMed2005

Reevaluating the association between emergency department heart rate and the development of posttraumatic stress disorder: A public health approach.

BACKGROUND: Preliminary investigations in select samples of trauma survivors presenting to acute care settings suggest an association between elevated emergency department heart rate (HR) and the subsequent development of posttraumatic stress disorder (PTSD). Other studies suggest no association, however. METHOD: In a prospective cohort study of a population-based sample of 161 acutely injured surgical inpatients, HR was assessed at initial presentation to the emergency department. Symptoms of PTSD were assessed with the PTSD Checklist at the time of the surgical inpatient hospitalization and 1, 4-6, and 12 months postinjury. RESULTS: Emergency department HR > or = 95 beats per minute (BPM) was a significant independent predictor of PTSD symptoms in analyses that adjusted for relevant injury, clinical, and demographic characteristics. This HR cutoff demonstrated modest specificity (range 60%-65%) and sensitivity (range 49%-63%) for the prediction of chronic PTSD. CONCLUSIONS: We found an independent association between elevated emergency department HR > or = 95 BPM and PTSD symptoms in a representative sample of injured acute care inpatients. Future investigations that incorporate clinical epidemiologic methods in the study of acute care biological parameters have the potential to improve the quality of mental health care delivered to injured survivors of individual and mass trauma.

Adult↗

PubMed2005

Rethinking the duration requirement for generalized anxiety disorder: evidence from the National Comorbidity Survey Replication.

BACKGROUND: The proposed revisions of the ICD and DSM diagnostic systems have led to increased interest in evaluation of diagnostic criteria. This report focuses on the DSM-IV requirement that episodes of generalized anxiety disorder (GAD) must persist for at least 6 months. Community epidemiological data are used to study the implications of changing this requirement in the range 1-12 months for estimates of prevalence, onset, course, impairment, co-morbidity, associations with parental GAD, and sociodemographic correlates. METHOD: Data come from the US National Comorbidity Survey Replication (NCS-R), a US household survey carried out during 2001-2003. Version 3.0 of the WHO Composite International Diagnostic Interview (WMH-CIDI) was used to assess DSM-IV anxiety disorders, mood disorders, substance disorders, and impulse-control disorders. RESULTS: Lifetime, 12-month, and 30-day prevalence estimates of DSM-IV GAD changed from 6.1%, 2.9%, and 1.8% to 4.2-12.7%, 2.2-5.5%, and 1.6-2.6% when the duration requirement was changed from 6 months to 1-12 months. Cases with episodes of 1-5 months did not differ greatly from those with episodes of > or = 6 months in onset, persistence, impairment, co-morbidity, parental GAD, or sociodemographic correlates. CONCLUSIONS: A large number of people suffer from a GAD-like syndrome with episodes of < 6 months duration. Little basis for excluding these people from a diagnosis is found in the associations examined here.

Adult↗

PubMed2005

Does the addition of cognitive behavioral therapy improve panic disorder treatment outcome relative to medication alone in the primary-care setting?

BACKGROUND: Randomized clinical trials indicate a benefit from combining medications with cognitive behavioral therapy (CBT) relative to medication alone for panic disorder. Using an as-treated analysis, we evaluated whether the addition of CBT enhanced outcomes for panic disorder relative to medications alone in the primary-care setting. METHOD: Primary-care patients with panic disorder reported on their receipt of CBT and medications over the 3 months following baseline assessment. The degree to which outcomes for those who used anti-panic medications were enhanced by the receipt of at least one component of CBT was analyzed using a propensity score model that took into account observable baseline patient characteristics influencing both treatment selection and outcomes. RESULTS: The addition of CBT resulted in statistically and clinically significant improvements at 3 months on anxiety sensitivity, social avoidance, and disability. Also, patients receiving CBT in the first 3 months of the study were more improved at 12 months than patients who took medications only during the first 3 months of the study. CONCLUSIONS: The clinical utility of the findings are discussed in terms of the importance of primary-care physicians encouraging their panic disorder patients to receive CBT as well as medications.

Adult↗

PubMed2005

The relationship between post-traumatic stress disorder, depression and cardiovascular disease in an American Indian tribe.

BACKGROUND: Empirical findings suggest that psychiatric illness is associated with cardiovascular disease (CVD). The purpose of this study was to compare the strength of the association of lifetime post-traumatic stress disorder (PTSD) and lifetime major depression on CVD among Northern Plains American Indians. METHOD: A total of 1414 participants aged 18-57 years completed a structured interview that assessed psychiatric diagnoses, alcohol abuse/dependence, self-reported CVD, and traditional CVD risk factors including age, sex, education, diabetes, high blood pressure, and smoking. Logistic regression analyses compared the odds ratios of CVD in participants with and without diagnosed PTSD or major depression. RESULTS: The rates of lifetime PTSD and major depression were 15% and 8% respectively. CVD was more commonly reported by participants with PTSD than by those without PTSD (12% v. 5%, p<or=0.01). Likewise, more participants with major depression reported CVD than did their non-depressed counterparts (14% v. 6%, p<or=0.05). PTSD was significantly associated with CVD even after controlling for traditional CVD risk factors and major depression (odds ratio 2.0, confidence interval 1.1-3.8). In contrast, the association of major depression with CVD was not significant after accounting for both traditional risk factors and PTSD. CONCLUSIONS: Rates of PTSD are high in American Indian communities. Rising CVD rates in this population may be better understood if PTSD is considered along with other traditional risk factors. Future research should examine the association and mechanisms of PTSD and CVD prospectively. Such data could lead to more effective CVD prevention efforts for American Indians.

Adolescent↗

PubMed2005

Should excessive worry be required for a diagnosis of generalized anxiety disorder? Results from the US National Comorbidity Survey Replication.

BACKGROUND: Excessive worry is required by DSM-IV, but not ICD-10, for a diagnosis of generalized anxiety disorder (GAD). No large-scale epidemiological study has ever examined the implications of this requirement for estimates of prevalence, severity, or correlates of GAD. METHOD: Data were analyzed from the US National Comorbidity Survey Replication, a nationally representative, face-to-face survey of adults in the USA household population that was fielded in 2001-2003. DSM-IV GAD was assessed with Version 3.0 of the WHO Composite International Diagnostic Interview. Non-excessive worriers meeting all other DSM-IV criteria for GAD were compared with respondents who met full GAD criteria as well as with other survey respondents to consider the implications of removing the excessiveness requirement. RESULTS: The estimated lifetime prevalence of GAD increases by approximately 40% when the excessiveness requirement is removed. Excessive GAD begins earlier in life, has a more chronic course, and is associated with greater symptom severity and psychiatric co-morbidity than non-excessive GAD. However, non-excessive cases nonetheless evidence substantial persistence and impairment of GAD, high rates of treatment-seeking, and significantly elevated co-morbidity compared with respondents without GAD. Non-excessive cases also have sociodemographic characteristics and familial aggregation of GAD comparable to excessive cases. CONCLUSIONS: Individuals who meet all criteria for GAD other than excessiveness have a somewhat milder presentation than those with excessive worry, yet resemble excessive worriers in a number of important ways. These findings challenge the validity of the excessiveness requirement and highlight the need for further research into the optimal definition of GAD.

Adolescent↗

PubMed2005

High utilizers of psychiatric emergency services.

OBJECTIVE: The purpose of this study was to examine the sociodemographic and clinical characteristics of high utilizers of psychiatric emergency services. METHODS: Data were collected over four years for 761 patients who were identified as high utilizers according to three definitions (two standard deviations above the mean number of visits to an urban psychiatric emergency service, six visits in a year, and four visits in a quarter) and for 1,585 nonfrequent utilizers (control group). Univariate analysis of variance and logistic regression models were used to determine group differences. RESULTS: Two distinct groups of high utilizers emerged: high utilizers by quarter and high utilizers by standard deviation. Compared with the control group, the high utilizers were more likely to be homeless, to have developmental delays, to be enrolled in a mental health plan, to have a history of voluntary and involuntary hospitalizations, to be uncooperative, to have personality disorders, to have unreliable social support, and to have a lifetime history of incarceration and detoxification. Compared with the high utilizers by quarter, the high utilizers by standard deviation had more visits and were more likely to have a history of incarceration and psychiatric hospitalization, more likely to be enrolled in mental health plan, and less likely to be homeless. CONCLUSIONS: High utilizers make up a small percentage of individuals who seek care in psychiatric emergency services and disproportionately use resources. It may be helpful to use two definitions of high utilizer to identify patients at different phases of their illness and to guide clinical interventions and mental health policies.

Adult↗

PubMed2005

Perceived unmet need for mental health treatment and barriers to care among patients with panic disorder.

OBJECTIVE: This study estimated the extent of perceived unmet need for mental health treatment among individuals with panic disorder in primary care settings, investigated the determinants of unmet need, and assessed barriers to care. METHODS: Data were from baseline interviews in a clinical trial that investigated primary care treatment of panic disorder. Participants were asked whether there was any time in the past three months when they did not get as much care for emotional or personal problems as they needed or whether they had delays in getting care. Patients who endorsed unmet need were asked about specific perceived barriers. Logistic regression was used to investigate the determinants of unmet need. RESULTS: Of the 231 patients eligible for the study, 88 (38 percent) endorsed unmet need for emotional or mental health problems. Individuals with worse mental health, those who were more worried about panic, and those without sick pay were significantly more likely to report unmet need. Commonly reported barriers included being unable to find out where to go for help (43 percent), worry about cost (40 percent), lack of coverage by health plan (35 percent), and being unable to get an appointment soon enough (35 percent). CONCLUSIONS: The relatively low level of patient-reported unmet need for mental health treatment among primary care patients with panic disorder suggests that efforts to improve treatment of panic disorder should include patient education about mental illness and the effective treatments available. Although discussion of barriers to care has traditionally centered on stigma and economic factors, the results of this study suggest that simple logistic factors, such as not knowing whom to call for help, are also important barriers.

Adult↗

PubMed2004

Clinicians' assessments of bipolar disorder and substance abuse as predictors of suicidal behavior in acutely hospitalized psychiatric inpatients.

BACKGROUND: Suicide is a major risk for those with bipolar disorder, a risk amplified by comorbid substance abuse in some, but not all, previous studies. To further explore the relationships of substance abuse, suicide, and bipolarity as they present in clinical practice, we analyzed standardized clinical data from a large acute psychiatric inpatient service. METHODS: Standardized clinical evaluations of 7819 patients with diagnoses of bipolar depression (n=990), bipolar mania (n=948), unipolar depressive episode (n=3626), or schizophrenia-schizoaffective disorders (n=2255) were analyzed to evaluate the relationship between current substance-use problems, substance-induced symptoms, and a current suicide crisis, as well as lifetime suicide attempts, with logistic regressions adjusting for age, gender, and ethnicity. RESULTS: Across the combined groups, current substance-use problems were significantly associated with a lifetime suicide attempt (odds ratios [ORs] 1.6-2.5) and to a lesser degree to the admission suicide crisis (ORs 1-2.2). Among bipolar (depressed/manic) patients, but not other diagnostic groups, those with both current substance-use problems and substance-induced symptoms had even higher rates of a recent suicide crisis (ORs 1.5-3.1) and of a lifetime attempt (ORs 2.5-3.4). CONCLUSIONS: In bipolar patients, substance use disorder doubled and substance use disorder plus substance-induced symptoms tripled the suicidal risk. Implications for future research are discussed.

Acute Disease↗

PubMed2004

A randomized effectiveness trial of stepped collaborative care for acutely injured trauma survivors.

CONTEXT: Although posttraumatic stress disorder (PTSD) and alcohol abuse frequently occur among acutely injured trauma survivors, few real-world interventions have targeted these disorders. OBJECTIVE: We tested the effectiveness of a multifaceted collaborative care (CC) intervention for PTSD and alcohol abuse. DESIGN: Randomized effectiveness trial. PARTICIPANTS: We recruited a population-based sample of 120 male and female injured surgical inpatients 18 or older at a level I trauma center. INTERVENTION: Patients were randomly assigned to the CC intervention (n = 59) or the usual care (UC) control condition (n = 61). The CC patients received stepped care that consisted of (1) continuous postinjury case management, (2) motivational interviews targeting alcohol abuse/dependence, and (3) evidence-based pharmacotherapy and/or cognitive behavioral therapy for patients with persistent PTSD at 3 months after injury. MAIN OUTCOME MEASURES: We used the PTSD symptomatic criteria (PTSD Checklist) at baseline and 1, 3, 6, and 12 months after injury, and alcohol abuse/dependence (Composite International Diagnostic Interview) at baseline and 6 and 12 months after injury. RESULTS: Random-coefficient regression analyses demonstrated that over time, CC patients were significantly less symptomatic compared with UC patients with regard to PTSD (P =.01) and alcohol abuse/dependence (P =.048). The CC group demonstrated no difference (-0.07%; 95% confidence interval [CI], -4.2% to 4.3%) in the adjusted rates of change in PTSD from baseline to 12 months, whereas the UC group had a 6% increase (95% CI, 3.1%-9.3%) during the year. The CC group showed on average a decrease in the rate of alcohol abuse/dependence of -24.2% (95% CI, -19.9% to -28.6%), whereas the UC group had on average a 12.9% increase (95% CI, 8.2%-17.7%) during the year. CONCLUSIONS: Early mental health care interventions can be feasibly and effectively delivered from trauma centers. Future investigations that refine routine acute care treatment procedures may improve the quality of mental health care for Americans injured in the wake of individual and mass trauma.

Adult↗

PubMed2004

Shorter duration of depressive episode may predict response to repetitive transcranial magnetic stimulation.

We investigated repetitive transcranial magnetic stimulation (rTMS) as a treatment for major depression. The experimental design comprised 15 medication-free subjects with major depressive disorder who were randomly assigned to receive 10 sessions of active or sham 10-Hz rTMS to the left dorsolateral prefrontal cortex at 110% motor threshold. Depression severity was measured by the Hamilton Depression Rating Scale (HDRS) and Beck Depression Inventory (BDI). Nonresponders to sham were allowed to receive active rTMS with the same parameters. Response to treatment was analyzed using a random regression model including episode duration and number of prior antidepressant treatments as covariates. Treatment (rTMS vs. sham) did not significantly predict changes in depression severity. Shorter duration of episode and more lifetime treatment trials significantly predicted improvements in BDI but not HDRS scores. Data from all subjects who received active rTMS (n = 14) showed that those with a depressive episode duration of shorter than 4 years had a mean HDRS decrease of 52% compared to 6% in those with an episode duration longer than 10 years. Active rTMS was well tolerated and was not associated with neuropsychological decrements when compared to sham. No significant antidepressant effects were found for 2 weeks of rTMS compared to sham. Among all subjects receiving rTMS those with a shorter duration of the current episode showed a greater response. Patients may need more than 10 treatments to obtain full benefit from rTMS. The design of future rTMS studies should consider these issues.

Adult↗

PubMed2004

Persistence and change of PTSD symptomatology--a longitudinal co-twin control analysis of the Vietnam Era Twin Registry.

INTRODUCTION: Previous twin studies have demonstrated a strong association between the degree of combat exposure and PTSD, and the continued presence of PTSD, almost two decades after combat. Independent genetic effects have also been demonstrated for both combat exposure and PTSD vulnerability in Vietnam veterans. The current study, involving a subset of male-male twin pairs discordant for service in Southeast Asia (SEA), is a follow-up to an earlier study conducted in 1987. The purpose of this study is to examine the changes in the combat exposure-PTSD relationship over an additional decade of time. METHODS: The Mississippi Scale for Combat-Related or Civilian PTSD was administered by telephone in 1997 during a follow-up survey of the Vietnam Era Twin Registry. Only twins discordant for service in Southeast Asia who originally participated in the 1987 study were included. Results of this scale and the original 1987 PTSD symptom scale were separately standardized using z-score transformations and used as dependent variables in a random effects regression model with zygosity, time and combat exposure as independent variables. Main effects and interactions were estimated to address whether there were differential effects of combat on PTSD over time, and whether there was evidence of genetic covariation between combat exposure and PTSD in 1987 that persisted to 1997. RESULTS: Combat exposure was strongly associated with PTSD in both 1987 and 1997. Although still highly significant, the effect sharply diminished over time. There is little evidence for a shared genetic vulnerability between combat and PTSD in either 1987 or 1997. CONCLUSION: This analysis documents the continuing role of combat exposure (i. e., trauma severity) on the persistence and chronicity of PTSD. Nearly 25 years after the end of hostilities, PTSD symptoms continue to be elevated in those exposed to the highest levels of combat. There is no evidence that genetic influences on exposure to combat are shared with those inducing a genetic vulnerability to PTSD. Clinicians need to be aware of the persistent and long-term residual effects of trauma exposure.

Humans↗