How Brothers and Sisters Are Linked To Midlife Crisis

Poor childhood sibling relationships are linked to major depression in adulthood, according to a new study.

The reason for the newfound relationship is unknown.

Reporting in the American Journal of Psychiatry, a team led by Harvard's Robert Waldinger looked at the histories of 229 men over thirty years, and for those who developed depression as adults, sought links to their childhood.

Confirming much other research, a family history of depression was also a strong independent predictor of adult depression.

The researchers also looked at the quality of parenting received in childhood, but once the quality of sibling relationships was taken into account, good or bad parenting did not seem to matter much. However, parents aren't off the hook yet -- Waldinger told the New York Times that “poor parenting may be reflected in poor sibling relationships.”

Adult Depression and Midlife Crisis

"Midlife crisis" is often used to describe what is really major depression (and several other issues that can arise in midlife).

Prior studies (here, here) have found that major depression has both genetic and environmental causes.

The newly documented link to sibling relationships extends other recent work. Two comprehensive analyses (here, and here) of risk factors for depression found that major depression is best predicted by:

• Internal factors such as genetics*, neuroticism, low self-esteem, early onset anxiety, and a (related) past history of major depression;
• "Externalizing" factors such as conduct disorder (being a "bad kid") and substance abuse;
• Recent adversity -- the strongest factor -- such as divorce, marital problems, and other difficult or stressful life events.

Further research will be required to see where childhood sibling issues fit into this complicated set of causes.

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* These studies found that genetic predisposition for major depression is a double-whammy: "Individuals at elevated genetic risk for major depression are likely to be exposed to higher rates of childhood adversity, to have higher levels of neuroticism, to have higher rates of early-onset anxiety disorder and substance misuse, and to select themselves into more difficulties and stressful life events in adulthood, all of which in turn increase risk for a depressive outcome."