Evidence for biochemical heterogeneity in schizophrenia: a multivariate study of monoaminergic indices in human post-mortal brain tissue.

A previously performed post-mortem study comparing monoaminergic indices in the brains of 14 schizophrenic patients and 10 patients with psychosis not diagnosed as schizophrenia, with age-matched control cases without any known neuropsychiatric illness, was re-investigated, using multivariate analysis. The monoaminergic patterns showing up in this analysis suggested the existence of at least two different forms of the disease, both of which could be distinguished from the controls as well as from each other. One of the schizophrenic groups consisted of paranoid cases, and had a relatively mild family history, whereas the other group, mainly consisting of hebephrenic cases, had a severe family history. The former group showed low levels of dopamine and high levels of serotonergic precursor and metabolite, whereas the latter group in some respects tended to show the opposite aberrations. Neuroleptic treatment did not seem to account for the different biochemical profiles, unless one assumes that this treatment can cause completely different monoaminergic aberrations in different individuals. Instead, one could argue that the different biochemical profiles found are characteristic of the disease.