thirds of bipolar patients have a family history of affective or emotional disorders, suggesting a hereditary factor is involved. Several studies have shown a genetic component to the disorder. Researchers at Johns Hopkins studying the inheritance patterns of the disorder believe that one gene underlies all these conditions (McKinnon et al, 2002). Kelsoe et al (2001) carried out a genome scan of bipolar disorder patients in a set of 20 families from the North American population. The regions of strongest linkage were found to be 22q and 13q. Linkage analysis in a further set of 32 families from the same population, which included subjects with bipolar I or bipolar II disorder, or with recurrent major depression, confirmed the presence of at least one bipolar susceptibility locus on both 22q and 13q. Other possible causes included a build up of calcium in the cells of bipolar patients, and evidence for the implication of dopamine and other neurotransmitters in the etiology of the disorder (Ford-Martin, 1999).
Diagnosis of bipolar disorder is done by a psychiatrist or psychologist treating a patient (Ford-Martin, 1999). This is done using verbal and written tests, administered to both inpatients and outpatients. The criteria listed in the DSM-IV are used as a guideline for the diagnosis of bipolar disorder.
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