There is a growing body of evidence implicating prenatal insults in the etiology of schizophrenia, although the etiological process is unclear. In this article we propose that prenatal exposure to alcohol may relate to a small fraction of patients who later develop schizophrenia.

Studies of extrapyramidal motor function in patients with schizophrenia have contributed to our understanding of the phenomenology and therapeutic outcome associated with neuroleptics. An increasing body of literature suggests that extrapyramidal motor abnormalities associated with schizophrenia may be linked to the pathophysiological mechanisms responsible for schizophrenia. Similarly, it has been documented that the extrapyramidal system may be involved in motor abnormalities in patients with Alzheimer's disease (AD). The present study was undertaken to examine motor function in schizophrenia and AD patients with psychosis. Quantitative instrumental procedures were used to examine rigidity, tremor, and bradykinesia in 13 neuroleptic-naive patients with schizophrenia, 13 AD patients with psychosis, and 26 age-comparable controls. Both schizophrenia and AD patients had significantly higher tremor and rigidity scores than did normal subjects. This comparative study of schizophrenia and AD patients with psychosis suggests that the effect of dementia in patients with psychosis is to prolong movement time, whereas abnormal parkinsonian postural tremor tends to be associated with psychosis in the absence of dementia.

The results of a new procedure for the quantification of tardive dyskinesia (TD) in the hand are reported. Fourier analyses were made of steady-state isometric force control in 41 neuroleptic-treated patients with and without hand TD. Results indicated that spectral analysis of isometric posture represents a reliable, sensitive, and valid measure of neuroleptic-induced dyskinesia.

One piece of genetic evidence for the biological distinctness of schizophrenia and bipolar illness is the rarity of monozygotic twin pairs in which one twin suffers from schizophrenia and the other from bipolar disorder. The authors describe a pair of monozygotic mirror-image twins with discordant diagnoses, schizophrenia in one twin and bipolar or schizoaffective disorder in the other.