An investigation into the genetic relationship between bipolar affective disorder and (idipathic) epilepsy in a sub-sahran African population

Abstract

Bipolar affective disorders and epilepsy have been linked by investigations concerning their phenomenology, neuro-biology and pharmacotherapy. One large Epidemiological study revealed that bipolar symptoms occurred in 12% of community-based epilepsy patients, a rate of about seven times higher than normal controls. Little is known however, if these observations are epiphenomena of an underlying genetic substrate, the establishment of which is an important step in the understanding of these disorders, such that we can predict, prevent and effectively manage them. Objective: To determine if there is a probable genetic relationship between bipolar affective disorder and epilepsy. Method: A case control study assessing the prevalence of epilepsy among the first degree relatives of patients with bipolar affective disorder and the prevalence of bipolar disorder among first degree relatives of patients with epilepsy compared to normal controls. Results: A total of 150 patients attending the outpatient clinic between March and July 2006 were recruited for the study (40 bipolar, 60 epileptics and 50 health controls). It revealed a significantly high prevalence of epilepsy among the first degree relatives of bipolar patients compared with healthy controls; 15.2% vs. 2.0% (x² = 46.08, p<0.001). There was similarly high and significant prevalence of bipolar affective disorder in first degree relatives of patients with epilepsy compared with normal control; 14.5% vs. 2.1 % (X² = 31.2, p<0.001). Conclusion: The biological links already noted by earlier studies between bipolar disorders and epilepsy seem to be strengthened by this findings of familial predisposition. This may be a prelude io other similar or more advanced studies to establish definite genetic link between these two important disorders.