Psychiatric disorders in individuals with methamphetamine dependence: prevalence and risk factors

Methamphetamine dependence may be associated with a range of psychiatric disorders. However, relatively few studies have systematically examined these disorders and possible risk factors. This study used a structured diagnostic interview to assess the prevalence and pattern of co-morbid psychiatric disorders in individuals with methamphetamine dependence; and identified risk factors for this comorbidity. One hundred adult volunteers with a diagnosis of methamphetamine dependence and without co-morbid medical disorders were consecutively recruited from three drug rehabilitation centres. Each volunteer was assessed with a socio-demographic questionnaire and evaluated for psychiatric comorbidity using the Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). A regression model was used to determine predictors of psychiatric comorbidity. Co-morbid psychiatric disorders were present in 36.0% of the sample; these included mood disorders (16.0%), psychotic disorders (13.0%) and anxiety disorders (7.0%). One in four of these disorders were assessed as being substance-induced. Independent predictors of psychiatric comorbidity included being male (OR = 10.04, 95% C.I = 2.07-48.63, p = 0.004), younger (OR = 0.87, 95% C.I = 0.77-0.99, p = 0.04), and having a previous psychiatric disorder (OR = 18.45, 95% C.I = 3.81-89.33, p < 0.001). Mood, psychotic, and anxiety disorders are common in individuals with methamphetamine dependence. Risk factors for such comorbidity can be identified. These findings underscore the need for an integrated model of care addressing both substance use disorders and psychiatric comorbidity.