Psychotherapeutic drugs and biogenic amines. Current concepts and therapeutic implications

Over the last 2 decades evidence has continued to accumulate from studies in various model systems that drugs effective in the treatment of major psychiatric disorders alter biogenic amines which function as neurotransmitters. As a result of these findings, various hypotheses have been formulated that there is a fundamental abnormality of one or another of the biogenic amine systems (i.e. the serotonergic, noradrenergic and dopaminergic systems) in the affective disorders and schizophrenia. Numerous attempts have been made to assess these biogenic amine hypotheses, primarily through quantitation of the major metabolites of the amines and recently by assessment of receptor sensitivity or density. The combination of basic pharmacological and clinical research has shown that there are biochemical subtypes, especially among those with affective illness, which might show a preferential response to biochemically specific drugs. If verified, such research constitutes a significant therapeutic advance. The status of these investigations is critically assessed in this review. Finally, many new techniques, challenge tests and biochemically distinct drugs are being introduced. Promising approaches that are likely to produce refinements of the biogenic amine hypotheses, as well as suggesting alternative formulations, are reviewed.