Detection of marijuana use in psychiatric patients by determination of urinary delta-9-tetrahydrocannabinol-11-oic acid.

Seventy-six male inpatients with diagnoses of schizophrenia, primary affective disorder, post-traumatic stress disorder, borderline personality disorder, other personality disorder, and primary substance abuse disorder were screened for the use of marijuana by determination of urinary delta-9-tetrahydrocannabinol-11-oic acid. Screening was performed to detect marijuana use in asymptomatic patients returning to the ward after passes, and also to elucidate changes in mental state in newly admitted patients and patients who had decompensated during hospitalization. Ward personnel found the screening procedure quite useful and incorporated it into psychotherapeutic and chemotherapeutic interventions. Although susceptible and resistant individuals were found in all diagnostic categories studied, no consistent features were found to distinguish those individuals who exhibited behavioral change in association with marijuana smoking, from those who did not.