Exploring the Relationship Between VMAT2 and DAT Expression, Psychotic Experiences, Craving, and Treatment Motivation in Male Patients with Methamphetamine Use Disorder

<b>Objectives:</b> We aimed to examine the relationship of Dopamine transporter (DAT) and vesicular monoamine transporter (VMAT-2) gene and protein levels with psychic experiences and other clinical parameters in individuals with Methamphetamine Use Disorder (MUD). <b>Methods:</b> This study included 50 males diagnosed with MUD and 50 males as a smoking control (SC) and nonsmoking control (NSC). Community Assessment of Psychic Experiences (CAPE) was administered to patients and controls; Addiction Profile Index, Treatment Motivation Questionnaire, and Substance Craving Scale were administered only to the patient group. DAT and VMAT2 gene and protein levels were determined in blood obtained from the controls and patient groups. <b>Results:</b> CAPE positive, depressive, total, and distress scores were significantly higher in the patient group. DAT protein level and <i>VMAT2</i> gene and protein levels were lower in the patient group compared to the controls. The <i>DAT</i> gene expression level was higher in the patient group compared to the controls. There was no correlation between any clinical variables and expression levels. A low <i>VMAT2</i> gene expression level could diagnose MUD with a 5% probability when NSCs were used as a reference. A high <i>DAT</i> gene expression level could diagnose tobacco use disorder (TUD) with a 99.9% probability when NSCs were used as a reference. <b>Conclusions:</b> The patient group showed more psychic experiences than healthy people. The low expression of the <i>VMAT2</i> gene was identified as a predictor of MUD, while the high expression of the <i>DAT</i> gene was predictive of TUD.