Cognitive vulnerability to bipolar disorder in offspring of parents with bipolar disorder.

Background: Bipolar disorder is a highly heritable illness, with a positive family history robustly predictive of its onset. It follows that studying biological children of parents with bipolar disorder may provide information about developmental pathways to the disorder. Moreover, such studies may serve as a useful test of theories that attribute a causal role in the development of mood disorders to psychological processes.

Method: Psychological style (including self-esteem, coping style with depression, domain-specific risk-taking, sensation-seeking, sensitivity to reward and punishment, and hypomanic personality and cognition) was assessed in 30 offspring of bipolar parents and 30 children of well parents. Parents of both child groups completed identical assessments.

Results: Although expected differences between parents with bipolar disorder and well parents were detected (such as low self-esteem, increased rumination, high sensitivity to reward and punishment), offspring of bipolar parents were, as a group, not significantly different from well offspring, apart from a modest trend towards lower adaptive coping. When divided into affected and non-affected subgroups, both groups of index children showed lower novelty-seeking. Only affected index children showed lower self-esteem, increased rumination, sensitivity to punishment, and hypomanic cognitions. Notably, these processes were associated with symptoms of depression.

Conclusion: Psychological abnormalities in index offspring were associated with having met diagnostic criteria for psychiatric illnesses and the presence of mood symptoms, rather than preceding them. Implications of the present findings for our understanding of the development of bipolar disorder, as well as for informing early interventions, are discussed.