Integrated viral genes as potential pathogens in the functional psychoses.

According to the retrovirus-transposon hypothesis, psychosis is due to the expression of a pathogenic sequence (a "virogene") integrated in the genome and either inherited from an affected or predisposed parent or acquired in the course of reproduction by a genetic rearrangement (e.g. a transposition or the generation of a tandem repeat). The psychoses are viewed as a continuum extending from unipolar through bipolar and schizo-affective disorder to schizophrenia with increasing severity of defect, movement along this continuum occurring by such genetic rearrangements. The locus at which these changes take place is envisaged as related to the genetic determinants of cerebral lateralisation (the "cerebral dominance gene") the interaction between potential pathogen and growth factor gene having possible growth enhancing effects. Such beneficial effects may have ensured the survival of this "hot-spot" in the genome.