BackgroundIn 1962 approximately 1.5 million French people living in Algeria were
repatriated to France in very poor and often life-threatening conditions.
These people constitute a cohort for the study of the long-term impact of
gene–environment interaction on depression.AimsTo examine the interaction between a highly stressful life event and
subsequent depression, and its modulation by a length polymorphism of the
serotonin transporter gene (5–HTTLPR).MethodA community sample of people aged 65 years and over residing in the
Montpellier region of the south of France was randomly recruited from
electoral rolls. Genotyping was performed on 248 repatriated persons and
632 controls. Current and lifetime major and minor depressive disorders
were assessed according to DSM-IV criteria.ResultsA significant relationship was observed between exposure to repatriation
and subsequent depression (P<0.002), but there was no
significant effect of gene alone (P = 0.62). After
controlling for age, gender, education, disability, recent life events
and cognitive function, the gene–environment interaction
(repatriation×5-HTTLPR) was globally significant
(P<0.002; OR = 3.21, 95% CI 2.48–5.12). Individuals
carrying the two short (s) alleles of 5-HTTLPR were observed to be at
higher risk (P<0.005; OR = 2.34, 95% CI 1.24–4.32),
particularly when repatriation occurred before age 35 years
(P<0.002; OR = 2.91, 95% CI 1.44–5.88), but this
did not reach significance in those who were older at the time of the
event (P = 0.067).ConclusionsThe association between depression and war repatriation was significantly
modulated by 5-HTTLPR genotype but this appeared to occur only in people
who were younger at the time of exposure.