Schizophrenia as a genetic encephalopathy

Evidence from a number of sources suggests that schizophrenia is primarily genetic in origin: it may be referred to as a "genetic encephalopathy". Intellectual deficits may precede or succeed onset of illness occasionally resulting in a true "dementia praecox". Structural changes in the brain (e.g. ventricular enlargement) are present early and according to a recent postmortem study have a degree of selectivity to the temporal horn on the left side of the brain; this suggests there is an arrest of development of cerebral asymmetry. It is proposed that the disease arises from an anomaly of the genetic determinants of asymmetry (the "cerebral dominance gene") located in the pseudo-autosomal (exchange) region of the sex chromosomes. Psychotic illness may represent a disadvantageous spin-off of the late evolutionary developments that led to the rapid increase in brain capacity in man.