The ongoing quest for sub-typing substance abuse : current status.

Substance abuse is a heterogenous disorder that necessitates classification for purposes of evaluation and treatment. Although a large number of typologies have been generated, the research has mostly focussed on alcoholism. The typologies of 'age at onset' and Cloninger's Type 1/Type2' have been extensively researched even though there is a lack of adequate validation. The present review of various typologies focusses more on the conceptual and methodological issues. A critique of the typological work is presented; highlighting the paucity of Indian research in this important area of substance abuse.