Mental health and cognitive function responses to quetiapine in patients with methamphetamine abuse under methadone maintenance treatment

•This study has evaluated the effects of quetiapine intake in MA abuse under MMT.•Quetiapine in MA abuse under MMT improved sleep and depression.•Quetiapine in MA abuse under MMT improved cognitive function. Patients with methamphetamine (MA) abuse under methadone maintenance treatment (MMT) are susceptible to several complications including cognitive disturbance and mental health disorder. This trial was designed to determine the impacts of quetiapine administration on cognitive function and mental health scale in patients with MA abuse under MMT. This study was carried out in 60 MA abusers under MMT. Patients were randomly allocated to receive either 100 mg quetiapine (n = 30) or control (n = 30) daily for 8 weeks. Cognitive function and mental health scale were taken at baseline and post-treatment to evaluate relevant variables. Quetiapine significantly decreased depression (b -3.94; 95% CI, -7.73, -0.16; P = 0.04) and sleep disorder (b -2.18; 95% CI, -2.89, -1.47; P