Lifetime prevalence of posttraumatic stress disorder in two American Indian reservation populations.

Posttraumatic stress disorder (PTSD) has been found to be more common among American Indian populations than among other Americans. A complex diagnosis, the assessment methods for PTSD have varied across epidemiological studies, especially in terms of the trauma criteria. Here, we examined data from the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (AI-SUPERPFP) to estimate the lifetime prevalence of PTSD in two culturally distinct American Indian reservation communities, using two formulas for calculating PTSD prevalence. The AI-SUPERPFP was a cross-sectional probability sample survey conducted between 1997 and 2000. Southwest (n = 1,446) and Northern Plains (n = 1,638) tribal members living on or near their reservations, aged 15-57 years at time of interview, were randomly sampled from tribal rolls. PTSD estimates were derived based on both the single worst and 3 worst traumas. Prevalence estimates varied by ascertainment method: single worst trauma (lifetime: 5.9% to 14.8%) versus 3 worst traumas (lifetime, 8.9% to 19.5%). Use of the 3-worst-event approach increased prevalence by 28.3% over the single-event method. PTSD was prevalent in these tribal communities. These results also serve to underscore the need to better understand the implications for PTSD prevalence with the current focus on a single worst event.

Social epidemiology of trauma among 2 American Indian reservation populations.

OBJECTIVES: We examined the prevalence of trauma in 2 large American Indian communities in an attempt to describe demographic correlates and to compare findings with a representative sample of the US population. METHODS: We determined differences in exposure to each of 16 types of trauma among 3084 tribal members aged 15 to 57 years through structured interviews. We compared prevalence rates of trauma, by gender, across the 2 tribes and with a sample of the US general population. We used logistic regression analyses to examine the relationships of demographic correlates to trauma exposure. RESULTS: Lifetime exposure rates to at least 1 trauma (62.4%-67.2% among male participants, 66.2%-69.8% among female participants) fell at the upper limits of the range reported by other researchers. Unlike the US general population, female and male American Indians exhibited equivalent levels of overall trauma exposure. Members of both tribes more often witnessed traumatic events, experienced traumas to loved ones, and were victims of physical attacks than their counterparts in the overall US population. CONCLUSIONS: American Indians live in adverse environments that place them at high risk for exposure to trauma and harmful health sequelae.

Challenges in operationalizing the DSM-IV clinical significance criterion.

BACKGROUND: An explicit clinical significance (CS) criterion was added to many DSM-IV diagnoses in an attempt to more closely approximate the clinical diagnostic process and reduce the proportion of false positives in epidemiological studies. The American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project (AI-SUPERPFP) offered a unique opportunity to examine the success of this effort. OBJECTIVE: To determine the impact of distress, impairment, and help-seeking reported in a lay structured interview on concordance with a clinical reappraisal. Further, to test the efficacy of 5 operationalizations of CS on the concordance and prevalence of DSM-IV lifetime disorders. DESIGN: Completed between 1997 and 2000, a cross-sectional probability sample survey with clinical reappraisal of approximately 10% of participants. SETTING: General community. PARTICIPANTS: A population-based sample of 3084 members of 2 American Indian tribal groups, who were between the ages of 15 and 54 years and resided on or near their home reservations, were randomly sampled from the tribal rolls and participated in structured psychiatric interviews. Clinical reappraisals were conducted with approximately 10% of the lay-interview participants. The response rate for the lay interview was 75%, and for the clinical reappraisal it was 72%. MAIN OUTCOMES MEASURES: The AI-SUPERPFP Composite International Diagnostic Interview (CIDI), a culturally adapted version of the CIDI, University of Michigan version. Adapted to assess DSM-IV diagnoses, questions assessing the CS criterion were inserted in all diagnostic modules. The Structured Clinical Interview for DSM-III-R (SCID) was used in the clinical reappraisal. RESULTS: Most participants who qualified as having AI-SUPERPFP CIDI lifetime disorders reported at least moderate levels of distress or impairment. Evidence of increased concordance between the CIDI and the SCID was lacking when more restrictive operationalizations of CS were used; indeed, the CIDI was very likely to underdiagnose disorders compared with the SCID (false negatives). Concomitantly, the CS operationalizations affected prevalence rates dramatically. CONCLUSION: The CS criterion, at least as operationalized to date, demonstrates little effectiveness in increasing the validity of diagnoses using lay-administered structured interviews.