Weissman et al (2016)

Uses: Genetics

AIM: To examine the familial aggregation of psychiatric disorder and functioning in grandchildren by their biological parent's and grandparent's depression status.

METHOD: Interview

PROCEDURE:

 Longitudinal retrospective cohort family study of 251 grandchildren (third generation with the mean age of 18 years old). They were interviewed a mean of 2.0 times and their biological parents interviewed a means of 4.6 times and their grandparents interviewed up to 30 years. The date of the study were from January 1982 all the way to June 2015.

Cumulative rates of psychiatric disorders and functioning collected for all generations by clinically trained interviewers and best-estimate diagnosis made blind to diagnoses in members of previous generations.

RESULTS:

 Original sample consisted of 91 families, of whom 77 families were eligible for inclusion, as some had grandchildren younger than 5 years of age. Out of 77, 62 decided to participate in the study. When only examining gen3, children of parents with MDD are 2 times more likely to have MDD, disruptive disorder, substance dependence, suicidal ideation and poor functioning than children whose parents do not have MDD. When gen3 were examined by parental and grandparental depression status, association of a parent's MDD on the grandchild's MDD but not other disorders varied with the grandparent's depression status. Grandchildren with both a depressed parent and grandparent have the highest risk for MDD. Children without a depressed grandparent, those with a depressed parent had overall poorer functioning but not higher rates of any of the disorders.

CONCLUSIONS:

In this study, biological offspring with 2 previous generations affected with major depression were at the highest risk for major depression, suggesting the potential value of determining family history of depression in children and adolescents beyond 2 generations. Early intervention in offspring of 2 generations affected with moderate to severely impairing MDD seems warranted, the specificity of the transmission of depression across 3 generations may make this group a homogeneous sample for biological marker studies.

If G1 have no depression and G2 have depression, G3 is not at an elevated rate to develop MDD.

Weissman MM, Berry OO, Warner V, et al. A 30-Year Study of 3 Generations at High Risk and Low Risk for Depression. JAMA Psychiatry. 2016;73(9):970–977. doi:10.1001/jamapsychiatry.2016.1586