Two Parents With Depression Don’t Spell Double Trouble for Offspring

Can one predict the mental health destiny of children who have one or two parents with a history of major depression? Past research has suggested that it is possible to do so. And now a large longitudinal, prospective, community study bolsters that hypothesis.

The study was conducted by Rosalind Lieb, Ph.D., of the Max Planck Institute of Psychiatry in Munich, Germany, and colleagues and was reported in the April Archives of General Psychiatry.

The study was based on some 2,400 14- to 24-year-olds in the Munich area. Half of these young persons had one or more parents who experienced a major depression at some point in their lives. The other half did not. Information about depression in the parents was obtained both from the parents and the young study subjects.

The subjects were assessed for the presence of various mental disorders at the start of the study and two more times over a four-year period. Diagnoses were based on DSM-IV, with information obtained with the Munich-Composite International Diagnostic Interview, an updated version of the World Health Organization’s Composite International Diagnostic Interview.

Lieb and her coworkers then used the data about the young people and their parents to see whether having one or more parents with a history of major depression could influence children’s mental health futures

Indeed, having either one or two parents with a history of major depression increased young people’s risk of also suffering a depression later in life, the researchers found. This finding was consistent with most previous reports by other researchers. It was, however, an extension of previous research, because associations were explored in a sample representative of the community and because young people were examined before they succumbed to mental illness. Also, the large sample size that Lieb and her coworkers studied gave extra strength to their finding.

What’s more, the young persons who later developed a major depression and who had parents with a history of major depression tended to experience a more malignant course than did those who became depressed but did not have parents with such a history. This finding was consistent with clinical studies that have linked parental depression with greater illness severity.

However, having two parents instead of one with a history of major depression did not increase young persons’ risk of developing a major depression, Lieb and her team discovered. This finding suggests that the familial transmission of major depression does not follow simple genetic patterns of transmission.

Also, having either a depressed mother or a depressed father appeared to impose a comparable risk of major depression on their subjects, they found. This result agreed with that of family genetic studies that had found no sex-specific effects in the familial transmission of a risk for major depression.

And can having parents with a history of major depression also increase a young person’s risk of developing a mental disorder other than major depression? The answer is yes, Lieb and her team determined. When the offspring of parents with no history of major depression were compared with the offspring of parents with such a history, the latter were found to experience higher rates of anxiety disorders, bipolar disorder, obsessive-compulsive disorder, posttraumatic stress disorder, and substance abuse disorders.

The researchers found that within-disorder associations—for example, parental depression with depression in offspring—were in most cases considerably higher than were cross-disorder associations such as parental depression with anxiety disorders in offspring. “Nevertheless, our cross-disorder findings also deserve attention,” they stressed in their study report. “The higher risk for nicotine dependence in offspring is especially interesting, as it has never before been reported.”

The study was funded by the German Ministry of Research and Technology.

An abstract of the study, “Parental Major Depression and the Risk of Depression and Other Mental Disorders in Offspring,” is posted on the Web at http://archpsyc.ama-assn.org/issues/v59n4/abs/yoa01030.html. ▪