Like many other psychological conditions there is thought to be a genetic element which can predispose people to developing bipolar disorder. People who suffer with bipolar disorder often have difficulties with their thought processes including impairments in verbal learning and memory, poor decision making and short attention spans. A Finnish study of 127 people looked at people suffering with bipolar disorder, their close relatives without the condition and a control group to see whether the relatives of bipolar disorder sufferers also had problems with their thought processes. If the relatives also had cognitive problems these could be caused by the same genes which led to people developing bipolar disorder and could be an important clue in helping researchers isolate the genes responsible for the condition. The study found that both the bipolar sufferers and their relatives had poor coordination and decision making (in psychological tests rather than major life decisions) although only the bipolar patients suffered from poor verbal learning and memory. The researchers concluded that poor coordination and decision making were the most important clues to a genetic link between bipolar patients and their relatives.
Antila, Mervi ... [et al] - Cognitive functioning in patients with familial bipolar I disorder and their unaffected relatives Psychological Medicine May 2007 37(5), 679-687