Age at onset typology in opioid-dependent men: an exploratory study from India.

This study attempted to apply age at onset typology in ICD-10-diagnosed opioid dependence. The sample is comprised of eighty men seeking treatment at an addiction clinic in India. The measures included a sociodemographic and clinical profile, Severity of Opioid Dependence Questionnaire, Sensation Seeking Scale, Multiphasic Personality Questionnaire (MPQ), and Family History Assessment Module. Application of k-means cluster analysis led to the emergence of two cluster types: early onset (mean age at onset 21 years) and late onset (mean age at onset 27 years). The early onset group was characterized by a significantly younger current age, more urban and unemployed subjects, younger ages at the onset of opioid use and dependence, a higher severity of opioid use, a higher lifetime use of sedatives and tobacco, younger ages at the onset of dependence on alcohol and cannabis, higher sensation seeking, and higher global psychopathology in terms of MPQ. Other less differentiating features were higher family history of psychiatric illness (including substance abuse), longer duration of opioid use and dependence, and higher lifetime use of cannabis. These results show the age at onset typology in opioid dependence to be feasible and to have some similarities to age at onset typology in alcoholism.