Parasitic infections and psychopathology: a preliminary hypothesis.

The relationship between chronic parasitic loads and psychopathology is examined. Research suggests that: (1) psychiatric disorders are more prevalent in less developed countries where parasitic loads are more endemic; (2) individual patients with parasitic loads are more likely to exhibit mental status changes; (3) there is an improvement in the mental status of a subset of psychiatric patients following treatment for parasites. Inasmuch as the prevalence of parasitic content is underestimated in both more developed and less developed countries, an awareness of this relationship should increase understanding of the needs of infected individuals, and be taken into consideration when evaluating psychiatric patients.