Harmful effects of substance abuse: a Darwinian perspective.

According to Griffiths and Mumford (1), psychotropic substances that have the potential to be used as drugs of abuse share two essential features: 1) they have positive reinforcing properties, that is, they induce pleasurable effects; 2) they can harm the individual who uses them and/or society. Current conceptualizations of substance abuse tend to consider positive reinforcing properties and harmful effects as two l a rgely independent features of drugs of abuse. This view is based on the assumption that hazards of substance abuse include adverse medical, psychiatric, and legal consequences, and that none of these consequences is strictly related to the capacity of drugs of abuse to induce pleasurable eff e c t s . In this paper I will analyze the harmful effects of substance abuse from a different perspective, namely, that of Darwinian psychiatry (2). This perspective postulates a close relationship between the positive reinforcing properties of drugs of abuse and their harmful effects. In line with previous articles that have focused on the evolutionary aspects of substance abuse (35), the basic thesis of this paper is that the harmful effects of drugs of abuse include not only