This study shares the limitations of all cross-sectional efforts. First, observed associations do not imply causal relationships. Second, sampling issues bear upon interpretation of findings. Our project collected data from only two American Indian reservation populations, and the extent to which these findings can be generalized beyond these communities is unknown. Likewise, our analyses included only participants reporting at least one significant trauma. Analyzing only exposed individuals maximized the clinical relevance and appropriateness of our conclusions about conditional risk, together with our ability to compare groups by exposure type. However, populations of inference were thereby further limited. In addition, our reliance upon self-report may have allowed participants to underreport stigmatizing traumas or symptoms. Finally, these findings represent the mental health status of two reservation communities between 1997 and 2000. We have compensated for the age of the dataset by restricting comparisons to the baseline NCS and DAST studies, both conducted close in time to AI-SUPERPFP. More importantly, AI-SUPERPFP's status as a large, landmark study—and one that is unlikely to be soon replicated—continues to recommend it as an important data source on PTSD among American Indians.
