Hair Analysis for Cannabinoids and Amphetamines in a Psychosis Incidence Study

The study explored the use of hair analysis to detect cannabinoids and amphetamines in patients during the pre-psychotic period. Out of 100 patients, 64 provided hair samples, but only 33 samples were long enough for analysis. Cannabinoids or amphetamines were detected in 9 samples, while 7 patients who reported drug use had no detectable substances, likely due to slower hair growth rates. The study concluded that hair analysis is limited by high refusal rates, insufficient hair length, and variability in individual hair growth rates, which affect its clinical usefulness.