Associations between methamphetamine and alcohol use disorder, suicidal ideation, and lowered quality of life in methamphetamine users

Aim: There is a strong comorbidity between methamphetamine (MA) and alcohol use whereby MA use may contribute to increased alcohol consumption. This study aims to determine the associations between alcohol drinking and MA-associated behaviors among MA users in relation to mood disorders, suicidal ideation, and health-related quality of life (HR-QoL). Methods: Substance use characteristics were obtained in 106 participants with MA use at a substance abuse treatment center by using the Severity of Dependence Scale (SDS) and the Thai version of the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA). Current alcohol drinking behaviors were estimated using the Substance Outcomes Profile (SOP), which was developed and translated from the Treatment Outcomes Profile, by computing the number of alcohol units x days per month of alcohol use. The Mini-International Neuropsychiatric Interview (M.I.N.I.) was used to estimate lifetime histories of mood disorders and substance abuse and current suicidal ideation. Results: Current suicidal ideation in MA users is to a large extent predicted by the severity of current alcohol and MA use, female gender, and a lifetime history of mood disorders (major depression, dysthymia, and hypo-mania). Moreover, a lifetime history of mood disorders is positively associated with the severity of MA, but not with alcohol use. Partial least squares (PLS) path modeling shows that lowered HR-QoL in MA users is predicted by the SDS score and alcohol dosing (both inversely) and that lifetime diagnoses of mood disorders and MA use (both inversely) and alcohol dependence (positively) have significant effects on HR-QoL which are completely mediated via the SDS score. Conclusions: In MA users, the severity of dependence, and MA and/or alcohol use exert adverse effects on current suicidal ideation and HR-QoL. Mechanistic explanations are given which may explain the inverse associations between the severity of MA and alcohol use in MA abusers.