Prevalence and correlates of cocaine physical dependence subtypes using the DSM-IV in outpatients receiving opioid agonist medication

The present study used a cross-sectional design to examine the relationship between endorsement of physiological dependence to cocaine (i.e., tolerance and/or withdrawal) and lifetime, and current problem severity (i.e., psychiatric and substance use disorders, medical and psychosocial problems) for opioid and cocaine dependent individuals (n=719) newly admitted to a treatment program using opioid-agonist medication. All participants completed the structured clinical interview for the Diagnostic and Statistical Manual (DSM-IV) (SCID-IV) and the Addiction Severity Index (ASI). Participants were first classified into physiological (n=549) versus non-physiological (n=170) cocaine dependence groups for one set of analyses and then categorized into one of four groups for further analyses: (1) tolerance only (n=215), (2) tolerance plus withdrawal (n=279), (3) withdrawal only (n=55) or (4) no physiological dependence (n=170). Those participants who endorsed physiological dependence reported higher rates of lifetime psychiatric and substance use disorders, higher rates of current drug use and more current problems. The four-group analyses showed that endorsement of withdrawal, with or without tolerance, was associated with the most severe problems. These findings suggest that physiological dependence to cocaine (particularly the presence of withdrawal) is a marker for a more severe substance use disorder and higher rates of comorbid psychopathology and other problems.