Which type of depression has the highest inherited risk?

Bipolar depression is associated with the highest inherited risk among various types of depression. Research consistently indicates that individuals with a family history of bipolar disorder have a significantly higher likelihood of developing the condition themselves, emphasizing the genetic component of this mood disorder. Studies show that if a first-degree relative has bipolar disorder, the risk of developing the disorder is notably increased compared to the general population.

In contrast, while unipolar depression, dysthymic disorder, and seasonal affective disorder can also have genetic components, their inherited risks are generally lower than those observed in bipolar disorder. Unipolar depression does have a hereditary aspect, but the genetic predisposition is not as strong as that for bipolar disorder. Dysthymic disorder, characterized by a chronic form of depression, and seasonal affective disorder, which occurs in relation to seasons and changes in daylight, also do not exhibit the same level of inherited risk, making bipolar depression unique in this aspect of its etiology.