Robert H. Yolken, Stanley Division of

Developmental Neurovirology, Johns Hopkins University School of Medicine

There is a growing consensus that most

diseases which are prevalent in the human population are complex disorders

caused by the interaction between genetic and environmental determinants. 

I hypothesize that schizophrenia and bipolar disorder are complex disorders and

that many cases are caused by the occurrence of infections and other

environmental insults in genetically susceptible individuals.  If this

hypothesis is correct, the natural history of schizophrenia and bipolar disorder

can be altered by the prevention and treatment of infection in such individuals.

There are a number of available

therapeutic agents which can modify the course of infectious diseases in humans.

These include antibiotics, anti-viral agents, anti-parasitic agents, and

modulators of the immune system. I will review microbial pathogens which may be

involved in the etiopathogenesis of human psychiatric disorders and

pharmacological interventions which are currently available for their prevention

and treatment.  Most antimicrobial medications have very low toxicity and

are suitable for clinical trials in which they are administered along with

standard psychoactive medications over prolonged periods of time.  The

evaluation of anti-microbial medications in carefully controlled clinical trials

of the treatment of psychiatric disorders will provide crucial information

related to the etiology of these diseases and may result in novel methods for

their treatment.