We did not anticipate, and rarely found, significant differences in conditional PTSD by tribe. Although such patterns have appeared for other diagnoses represented in AI-SUPERPFP data [11,16,28-30], their absence here may reflect the ubiquity of trauma exposure in the participating communities. Our ethnographic work has also suggested that PTSD diagnosis has considerable cultural validity across both tribes [31-33]. We did observe a significant relationship between trauma type and tribe for one category of event: SW participants experiencing non-interpersonal trauma confronted greater risk of PTSD than did their NP counterparts. Non-interpersonal events tended to be less frequent in the SW than in the NP (see Table 2). Whether the relative uniqueness of non-interpersonal events was important or whether the non-interpersonal events differed in severity across tribes merits future consideration.
