Clinical Course of Methamphetamine-Induced Psychotic Disorder in a 3-Month Follow-Up.

Objective To assess the clinical course of patients with methamphetamine-induced psychotic disorder (MIPD) and any possible predictors of the clinical course in a 3-month follow-up. Methods This prospective cohort study included 50 patients (7 female, 43 male) with MIPD and was performed from September 2014 to October 2015. Patients were assessed during hospitalization and in a follow-up visit 3 months later. Diagnoses were made using interviews based on the Structured Clinical Interview for DSM-IV Axis I Disorders. Positive, negative, manic, and depressive symptoms were the main outcome measures that were assessed using the Scale for the Assessment of Positive Symptoms, Scale for the Assessment of Negative Symptoms, Young Mania Rating Scale, and Hamilton Depression Rating Scale, respectively. Paired t test and regression analysis were used to analyze the data. Results Forty-six patients (92%) were reassessed at follow-up. More than half of the patients relapsed to methamphetamine use, did not adhere to treatment, and were functionally impaired. Positive, negative, and manic symptoms, but not depressive symptoms, improved in abstinent patients (P < .001, P = .001, P < .001, and P = .395, respectively). The best predictor of depressive and negative symptoms at follow-up was the patients' respective baseline scores; but positive and manic symptoms were best predicted by reuse of methamphetamine during follow-up. Conclusions Various symptom categories do not always change in the same direction during the course of the disorder, especially depressive symptoms that do not improve with abstinence but aggravate with frequency of methamphetamine use. Negative symptoms at baseline also seem to have a possible role in prediction of methamphetamine reuse in patients with MIPD. Physicians should be advised to independently address all of the symptom categories of their patients with MIPD at each follow-up visit.