At Issue: An Un-Dopamine Hypothesis of Schizophrenia

The dopamine hypothesis of schizophrenia is examined critically. Although the hypothesis is couched in chemical terms, the evidence is primarily pharmacologic. In addition, neuroleptic mechanisms do not fit a simple hyperdopaminergic formulation, and treatment efficacy points to a general psychotic rather than specific schizophrenic role for dopamine. Most compromising to the hypothesis is the therapeutic action of L-dopa when combined with neuroleptics in chronic schizophrenics. Dopamine appears important but cannot be viewed as a simple pathogen.