Neurocognition and affective temperament in first-degree relatives of patients with bipolar disorder in south India: a cross-sectional study

Endophenotypes aid in studying the complex genetic basis of bipolar disorder. We aimed to compare first-degree relatives of patients with bipolar I disorder in a hospital in India with unrelated healthy controls in terms of neurocognition and affective temperament METHODS. This cross-sectional study was conducted between August and November 2012 at a tertiary hospital in India. First-degree relatives (parents, siblings, and children) of patients with bipolar I disorder were included; they were aged 18 to 50 years and had education level of at least eighth grade. Additionally, matched healthy controls were recruited from the general population. Sociodemographic data were collected using a semi-structured proforma. Participants were assessed for verbal and visual working memory, executive function (including cognitive flexibility, response inhibition, as well as concept formation, abstract reasoning, and set-shifting abilities), and affective temperament by a single investigator.

Of the 52 first-degree relatives of patients diagnosed with bipolar I disorder, 30 were included in the analysis. Additionally, 30 matched healthy controls from the general population were included for comparison. Compared with healthy controls, first-degree relatives performed significantly poorer in all tests and had significantly higher scores for cyclothymic, hyperthymic, and anxious temperaments.

Impairments in working memory, executive function, and certain affective temperaments are potential endophenotypes for bipolar I disorder. Working memory and executive function are most important cognitive domains for social, occupational, and interpersonal functioning. These potential markers could be used to trace susceptible genes for bipolar disorder and thus enhance our understanding of the complex genetics of mood disorders.