Early-onset of illicit substance use is associated with greater axis-II comorbidity, not with axis-I comorbidity

In the present study the relationship between early-onset ( < age of 18) of illicit drug use disorder, DSM axis-I disorders, and axis-II symptomatology was investigated in order to identify a subclassification of these patients. Patients with drug use disorders (n = 174) attending an inpatient detoxification clinic comprised the study sample. Before detoxification treatment, all patients were administered the Addiction Severity Index (ASI) in order to investigate drug use severity and severity of drug related problems. After detoxification the patients were administered the Composite International Diagnostic Interview (CIDI) for assessing DSM axis-I disorders and the Questionnaire on Personality Traits (VKP) for assessing DSM axis-II symptomatology. Except for medical problems, no differences between the early- and late-onset groups on addiction severity and addiction related problems were found. Furthermore, no associations between lifetime prevalence of any axis-I disorder and onset group were observed. In contrast, patients with an early-onset of substance use disorder had significantly higher antisocial, borderline, and passive-aggressive personality symptomatology than patients with a late-onset. These results are discussed in relation to the classification of drug dependent patients. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.