Genetic risk

A lifetime prevalence of bipolar I disorder in community samples ranges from 0.5 to 1.5%. This rises to 4-9% in their first degree biological relatives. There is also a raised rate of bipolar II disorder (1-5%) and major depressive disorder (8-20%) in these relatives. A combination of twin and adoption studies suggests that a substantial proportion of illness risk is genetic. Due to the absence of a reliable genetic or an early fetal marker, genetic counselling is limited to providing information on these wide ranges of risk.1

References

  1. Scottish Intercollegiate Guidelines Network. Bipolar affective disorder: A national clinical guideline. Scottish Intercollegiate Guidelines Network. 2005; May