Cognitive impairment in methamphetamine users with recent psychosis: A cross-sectional study in Thailand.

BACKGROUND: Cognitive impairment in methamphetamine (MA) users with psychosis may be more severe than that in MA users without psychosis. This study aimed to compare the overall cognitive function and specific cognitive domains between MA users with and without psychosis. METHODS: Participants in this cross-sectional study were adult inpatients who used MA within the month prior to admission. The recent use of MA was confirmed using quantitative analysis of hair. We used the Mini International Neuropsychiatric Interview (MINI) - Plus, Psychotic Module to confirm the presence of recent psychosis in the participants who fulfilled the inclusion criteria, excluding the individuals with a lifetime history of schizophrenia. We assessed the severity of depression and MA withdrawal using the Patient Health Questionnaire (PHQ-9) and the Amphetamine Withdrawal Questionnaire. The severity of cognitive impairment was assessed using the Montreal Cognitive Assessment (MoCA). The MoCA total and subtest scores were used to compare participants with and without psychosis. RESULTS: Participants included 113 MA users with psychosis and 120 MA users without psychosis. Those with psychosis had significantly lower MoCA total, visuaospatial/executive subtest, and abstract subtest scores than those without psychosis (mean differences=-0.8, -0.3, and -0.2, respectively). The association between MA psychosis and the MoCA total scores was still statistically significant after the adjustment for years in education in an ordinal logistic regression analysis. CONCLUSIONS: MA users with psychosis had poorer overall cognitive function than MA users without psychosis. The cognitive impairment is prominent in the domains of visuospatial/executive function and abstraction.

Risks of psychosis in methamphetamine users: cross-sectional study in Thailand.

OBJECTIVE: To determine factors related to recent methamphetamine-associated psychosis (MAP) among individuals recently using methamphetamine (MA). DESIGN: Cross-sectional study carried out between July 2015 and June 2017. SETTING: Four mental health hospitals and one substance abuse treatment centre in Thailand. PARTICIPANTS: Individuals recruited onto the study included those aged 18 years or over, of both sexes, who reported MA use in the month prior to admission. MEASURES: Any recent psychosis was confirmed using the Mini International Neuropsychiatric Interview-Plus psychotic module. The Timeline Follow Back was used to determine days of MA use. The severity of MA dependence was assessed using the Severity of Dependence Scale. Quantitative hair analysis was carried out to confirm recent use of MA and to measure the amount of MA use. We compared several characteristics between those who had recently experienced psychosis and those who had not. RESULTS: This study included 120 participants without MAP and 113 participants with MAP. The mean age was 28 years and the mean abstinence was 17 days. The levels of MA concentration in hair were not significantly different between groups (p=0.115). Based on the final logistic regression model, the independent factors associated with MAP (OR and 95% CI) included being male (OR 4.03, 95% CI 1.59 to 10.20), ≥16 days of MA use in the past month (OR 2.35, 95% CI 1.22 to 4.52), MA dependence (OR 9.41, 95% CI 2.01 to 44.00) and hospitalisation history related to substance abuse (OR 3.85, 95% CI 2.03 to 7.28). CONCLUSIONS: Health professionals should closely monitor the development of MAP in MA-dependent men who frequently use MA and have a history of hospitalisation for substance abuse. The measure of MA concentration levels in the hair may add no benefit for the prediction of the development of MAP.