Negative dimension in psychiatry. Amotivational syndrome as a paradigm of negative symptoms in substance abuse.

Negative symptoms, conceptualized as clinical manifestations of schizophrenia, and subsequently described in other psychiatric disorders, include the loss of normal arousal, drive and affective reactivity. In the field of substance abuse, an interesting analogy can be detected between negative symptoms, in their classical meaning, and the amotivational syndrome (AS), which has been described as a form of chronic cannabis intoxication. AS also shows a close resemblance to the reward deficiency syndrome (RDS) of alcoholics and stimulant abusers, and to the post-withdrawal syndrome (PWS) of detoxified heroin addicts. A variety of substances share a common tropism for the dopaminergic system, leading to a state of hypophoria, which seems to represent a common pathway for chronic substance abusers. In the light of these convergences, a common treatment principle for addictive disorders can be enunciated. This consists in resorting to pro-dopaminergic drugs, that are supposed to replace damaged functions and control craving, and in avoiding anti-dopaminergic drugs, that are expected to exacerbate craving and impede the reversal of the reward deficiency.