The development of antipsychotic drugs

Abstract

Antipsychotic drugs revolutionised psychiatric practice and provided a range of tools for exploring brain function in health and disease. Their development and introduction were largely empirical but based on long and honourable scientific credentials and remarkable powers of clinical observation. The class shares a common core action of attenuating central dopamine transmission, which underlies the major limitation to their use - high liability to disrupt extrapyramidal function - and also the most durable hypothesis of the basis of psychotic disorders, especially schizophrenia. However, the Dopamine Hypothesis, which has driven drug development for almost half a century, has become a straight-jacket, stifling innovation, resulting in a class of compounds that are largely derivative. Recent efforts only cemented this tendency as no clinical evidence supports the notion that newer compounds, modelled on clozapine, share that drug's unique neurological tolerability and can be considered 'atypical'. Patients and doctors alike must await a more profound understanding of central dopamine homeostasis and novel methods of maintaining it before they can again experience the intoxicating promise antipsychotics once held.

Keywords: Antipsychotics; atypical antipsychotics; clozapine; dopamine; extrapyramidal side-effects; pharma investment.

Figure 1.

Antipsychotic drugs: schematic representation of some receptor-binding profiles (percentages of total binding: for method of calculation, see Hyttel et al., 1984 and Goldstein, 2000).