Validation of a modified version of the PRIME screen for psychosis-risk symptoms in a non-clinical Kenyan youth sample

Background The PRIME screen is a self-administered questionnaire designed to quickly assess individuals at risk for developing a psychotic disorder. It is shorter in both length and administration time compared to the Structured Interview for Psychosis-Risk Syndromes (SIPS) - a standard instrument for psychosis prodromal risk assessment. Validation of the PRIME against the SIPS has not been reported in large non-clinical populations. Methods A culturally modified version of the PRIME screen (mPRIME) was administered to Kenyan youth between the ages of 14 and 29. 182 completed both the SIPS and mPRIME. Validation measures (sensitivity, specificity, positive predictive value, negative predictive value) were calculated and the study sample was then broken down into true positives, false positives, and false negatives for comparison on different quantitative measures. Results Using previously suggested thresholds for a positive screen, the mPRIME had a sensitivity of 40% and a specificity of 64.8% for our entire sample. Positive predictive value (PPV) and negative predictive value (NPV) were 12.3% and 89.7%, respectively. Breaking the sample down by questionnaire outcome showed that true-positive individuals scored higher on average rate and intensity of endorsement of mPRIME items compared to false-positive and false-negatives, while false-negatives on average registered disagreement on all mPRIME questionnaire items. Conclusions The mPRIME does not appear to be an effective screener of at-risk individuals for psychosis in our non-clinical sample. Further validation efforts in other general populations are warranted.