The platelet as a peripheral marker in psychiatric illness

The identification of peripheral markers of psychiatric illness is importan t if an improvement in the diagnosis and treatment of various diseases with overlapping symptomatology is desired. There are many disorders that not o nly have overlapping symptomatology. but also have similar biological distu rbances. The functional capability of the neurons involved in the disease p rocesses may be at the crux of the underlying pathology. The platelet intra cellular calcium response to neurotransmitter stimulation has previously be en used as a peripheral marker of psychiatric illness. This review discusse s evidence in support of the extended use of the platelet as a peripheral m arker. The use of the platelet intracellular calcium response to neurotrans mitter stimulation as a state or trait marker in major depression, the spec ificity and selectivity of this response, and the possible use of the plate let as a peripheral marker in psychotic disorders such as schizophrenia, ma nia and psychotic depression are shown. Finally, a proposed mechanism for t he association between certain psychiatric disorders and cardiovascular dis ease is discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.