Comorbid psychiatric diagnoses and their association with cocaine-induced psychosis in cocaine-dependent subjects.

Comorbidity between drug abuse and mental illness is very common, but the association of such comorbidity with specific responses to drugs of abuse remains obscure. The current study examined the relationship between the presence of non-psychotic Axis I psychiatric diagnoses and the frequency and severity of cocaine-induced psychosis. We interviewed 243 unrelated cocaine-dependent adults [37% European American (EA), 52.3% African American (AA); 58.8% male] using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) to establish DSM-IV diagnoses, and two instruments for the identification of cocaine-induced paranoia, the Cocaine Experience Questionnaire (CEQ) and the Scale for Assessment of Positive Symptoms for Cocaine-Induced Psychosis (SAPS-CIP). Comorbid substance use and psychiatric disorders were common in this cocaine-dependent sample. Ninety percent of subjects met criteria for substance use disorders other than cocaine dependence; common non-substance-use disorders included antisocial personality disorder (ASPD), adult ASPD, major depression, and attention deficit-hyperactivity disorder (ADHD). Comorbid opioid dependence was more common in EA subjects than in AA participants. After correction for multiple comparisons, a lifetime diagnosis of ADHD was associated with the categorical presence of CIP (p = 0.007), as well as significantly more severe CIP symptoms. Comorbid substance use and psychiatric disorders are very common among individuals with cocaine dependence. Comorbid ADHD increases the odds of an individual endorsing CIP, suggesting some common basis for these phenomena.