Increasing
risk of depression through three generations
Numerous
family studies of adults have shown the familial
character of major depression and studies of
offspring of parents with major depression show
a 3-fold higher risk of developing depression
among children. None of the published studies
have gone beyond 2 generations. A recent study
investigated the familial aggregation of
psychiatric disorders by following-up
grandparents (generation 1) with and without
depression, their children (generation 2) up to
the age adult and had their own children
(generation 3) who were aged an average of 12
years.
A longitudinal, retrospective cohort, family
study examined the effect of the parents' and
grandparents' depression status on the
prevalence of psychiatric disorders and the
functioning of 161 participant grandchildren.
Diagnostic interviews were conducted and
diagnostic assessments were administered by
clinicians blind to diagnoses of previous
generations and to previous history
information.
A proportion (59.2%) of grandchildren who had
both parents and grandparents with depression
already had a psychiatric disorder (at the age
of 12 years). The risk of anxiety disorders in
these grandchildren was increased five fold in
comparison with those whose grandparents were
depressed but parents were not. Moreover, if
impairment criteria are added to the depression
diagnosis, 67.6% of the grandchildren with two
generations with depression had a psychiatric
disorder. The risk of developing a psychiatric
disorder was not higher in children whose
parents were depressed but whose grandparents
were not. However, grandchildren with a
depressed parent had poor overall mental
functioning, regardless of their grandparents'
depression.
Thus, information on family history of
depression, on its severity and impairment, is
important for identifying subjects at high risk
of developing psychiatric disorders at an early
age. Young children with depressed parents and
grandparents, who present anxiety disorders,
should be treated for depression without
waiting. Weissman
MM, Wickramaratne P, Nomura Y, Warner V, Verdeli
H, Pilowsky DJ, Grillon C, Bruder G. Families at
high and low risk for depression: a 3-generation
study. Arch Gen Psychiatry 2005, 62:
29-36.