An examination of psychiatric comorbidities as a function of gender and substance type within an inpatient substance use treatment program

Background: There are elevated rates of comorbid psychiatric disorders among individuals with substance dependence; however, little research examines these rates within inpatient settings, particularly in relation to gender and type of substance. The current study aimed to fill this gap. Method: 465 patients (71.4% male) were recruited from an inpatient substance use treatment facility from 2006 to 2009. These patients were interviewed and diagnosed using the Structure Clinical Interview for DSM-IV and the Diagnostic Interview for Personality Disorders. Results: 60.6% of patients with substance dependence had a current comorbid psychiatric disorder, and more than 30% had at least two psychiatric disorders. The most common current Axis I diagnosis was major depressive disorder (25.8%), followed by PTSD (14%). Comparable rates were found for Antisocial and Borderline Personality Disorders. Females were significantly more likely to meet diagnostic criteria for a psychiatric disorder than were males (73.7% versus 55.4%). When examining comorbidities across different substance dependences, the highest rates of comorbid psychiatric disorders were found among individuals with alcohol dependence (76.8%) and cannabis dependence (76%), although rates were above 60% for cocaine and opioid dependence. Rates of psychiatric diagnoses were significantly lower (27%) among patients who did not meet diagnostic criteria for substance dependence. Conclusions: There are particularly elevated rates of psychiatric disorders among individuals with substance dependence in inpatient treatment. These rates differ as a function of substance dependence type and gender, making these factors important to consider when researching and treating this type of population.