Posttraumatic stress disorder in injured adults: Etiology by path analysis

Objective: Posttraumatic Stress Disorder (PTSD) impairs outcome from injury . We present a path analysis of factors related to the development of PTSD in injured adults. Methods: A prospective cohort of 250 patients without severe neurotrauma wa s evaluated by interview during admission and by mailed self-report 6 month s later. Data were gathered from the trauma registry (age, injury mechanism , and Injury Severity Score), social history (gender, income, education, an d social support), and survey instruments. Baseline assessment used the Mic higan Critical Events Perception Scale (peritraumatic dissociation and subj ective threat to life), the Life Experience Survey (stressful exposure hist ory), and the SF36 (general and mental health). PTSD at 6 months was identi fied with the civilian Mississippi Scale for PTSD. Data are listed as mean +/- SEM or percent (%). Path analysis was conducted by linear regression an d significant (p < 0.05) variables are shown. Factors are listed with the s tandardized beta. A negative beta suggests a protective effect. Results: The 176 patients (72%) who completed the 6-month follow-up were 37 .7 +/- 0.88 years old; 75% were men; and blunt (70%), penetrating (13.5%), and burn (16.4%) mechanisms caused the injuries. Assault was involved in 14 .5% of the cases. Average income was $44,300 +/- 2,700/yr, education was 13 .0 +/- 0.15 years, and Injury Severity Score was 13.9 +/- 0.50. A total of 42.3% of the patients developed PTSD. The 39.7% of the variance in PTSD exp lained by the model was due to intentional injury (beta = 0.27), male gende r (beta = -0.21), age (beta = -0.20), peritraumatic dissociation (beta = 0. 174), baseline mental health (beta = -0.21), and prior life-threatening ill ness (beta = -0.29). Peritraumatic dissociation was due to the patient's se nse of threat to life (beta = -0.47), and threat was related to Injury Seve rity Score (beta = 0.2), assault(beta = 0.14), education (beta = -0.15), an d age (beta = -0.19). Baseline SF36 mental health was related to social sup port (beta = 0.27) and income (beta = 0.21). Income was contingent on educa tion (beta = 0.21). Conclusion: PTSD occurred in 42.3% of injured adults 6 months after trauma and was related to assault, dissociation, female gender, youth, poor mental health, and prior illness. By modeling PTSD, we may learn more of the etio logy, risk stratification, and potentials for the treatment of this common and important morbidity of injury.