Differential etiology of posttraumatic stress disorder with conduct disorder and major depression in male veterans.

BACKGROUND: Epidemiologic studies reveal that posttraumatic stress disorder (PTSD) is highly comorbid with both conduct disorder and major depression in men. The genetic and environmental etiology of this comorbidity has not been examined. METHODS: Data were analyzed from 6744 middle-aged male-male monozygotic and dizygotic twins from the Vietnam Era Twin Registry. Conduct disorder, major depression, and PTSD were assessed via telephone interview using the Diagnostic Interview Schedule for the DSM-III-R in 1992. Structural equation modeling was used to estimate additive genetic, shared environmental, and individual-specific environmental effects common and specific to conduct disorder, major depression, and PTSD. RESULTS: The association between conduct disorder and PTSD was explained primarily by common shared environmental influences; these explained 10% (95% confidence interval: 6%-17%) of the variance in PTSD. The association between major depression and PTSD was largely explained by common genetic influences; these explained 19% (95% confidence interval: 11%-26%) of the variance in PTSD. CONCLUSIONS: Our findings suggest that different etiologic mechanisms explain the association of conduct disorder and major depression with PTSD in male veterans. If replicated in other populations, results suggest research aimed at identifying specific genetic and environmental factors that influence PTSD may benefit from starting with those that have been more consistently and strongly associated with major depression and conduct disorder.     

The impact of preoperative skin disinfection on preventing intraoperative wound contamination

The efficacy of total body showering and incision site scrub with disinfectant agents was evaluated in a randomized, prospective study of 575 patients undergoing selected surgical procedures. Patients who showered twice with 4% chlorhexidine gluconate had lower mean colony counts of skin bacteria at the surgical incision site in the operating room prior to the final scrub than patients who showered twice with povidone-iodine solution or medicated bar soap. Patients in the chlorhexidine group had no growth on 43% of the incision site skin cultures compared with 16% in the povidone-iodine group and 6% in the soap and water group. Patients who showered and who were scrubbed with chlorhexidine also had lower rates of intraoperative wound contamination. Bacteria were recovered from the wounds of 4% of patients using this regimen compared with 9% for patients who used povidone-iodine and 15% for patients who showered with medicated soap and water and were scrubbed with povidone-iodine. We noted no difference in surgery-specific infection rates among patients in the three treatment groups; however, our sample sizes were too small to evaluate this outcome parameter adequately. These data suggest that preoperative showering and scrubbing with chlorhexidine is an effective regimen to reduce extrinsic intraoperative contamination of the surgical wound from skin bacteria. The efficacy of this regimen to prevent postoperative wound infection needs to be evaluated in a well-designed, carefully controlled prospective trial with adequate numbers of patients to achieve statistically valid conclusions.     

Implosive therapy for the treatment of combat-related PTSD

Implosive therapy for the treatment of post-traumatic stress disorder is based on the principle of exposing the patient to trauma-related cues until there is a reduction in the anxiety associated with the cues. It is a relatively specialized procedure regarding which few clinicians receive extensive supervised training, despite the numerous case studies that demonstrate its effectiveness. The present paper addresses a number of procedural issues and offers guidelines for conducting implosive therapy with traumatized combat veterans. Elements of controversy regarding the application of implosive therapy are discussed.     

Identification of the phenotype in psychiatric genetics

Summary Statistical procedures and molecular genetic techniques have attained a fine degree of resolution. Their ability to find disease genes has revolutionized medicine and raised hopes for breakthroughs in psychiatry. However, such breakthroughs may require an equally discriminating nosology. A psychiatric genetic nosology seeks to classify patients into categories that correspond to distinct genetic entities by addressing the problem of diagnostic accuracy: the degree to which a diagnosis correctly classifies people with and without a putative genetic illness. We review methods that deal with misclassification in genetic studies. These are clinical and epidemiological approaches that deal directly with how to define the observable manifestation of a putative genotype. We discuss two groups of methods: those that use known phenotypes and those that design new phenotypes.     

Home ventilation in Northern Ireland.

Thirteen patients were identified as receiving assisted ventilation at home in Northern Ireland in 1994. Two patients have since died. An increasing number of patients are starting home ventilation, especially by nasal mask. Recognition of the needs of these patients and provision of care require further consideration.