The impact of schizophrenia and mood disorder risk alleles on emotional problems: investigating change from childhood to middle age.

BACKGROUND: Previous studies find that both schizophrenia and mood disorder risk alleles contribute to adult depression and anxiety. Emotional problems (depression or anxiety) begin in childhood and show strong continuities into adult life; this suggests that symptoms are the manifestation of the same underlying liability across different ages. However, other findings suggest that there are developmental differences in the etiology of emotional problems at different ages. To our knowledge, no study has prospectively examined the impact of psychiatric risk alleles on emotional problems at different ages in the same individuals.

METHODS: Data were analyzed using regression-based analyses in a prospective, population-based UK cohort (the National Child Development Study). Schizophrenia and major depressive disorder (MDD) polygenic risk scores (PRS) were derived from published Psychiatric Genomics Consortium genome-wide association studies. Emotional problems were assessed prospectively at six time points from age 7 to 42 years.

RESULTS: Schizophrenia PRS were associated with emotional problems from childhood [age 7, OR 1.09 (1.03-1.15), p = 0.003] to mid-life [age 42, OR 1.10 (1.05-1.17), p < 0.001], while MDD PRS were associated with emotional problems only in adulthood [age 42, OR 1.06 (1.00-1.11), p = 0.034; age 7, OR 1.03 (0.98-1.09), p = 0.228].

CONCLUSIONS: Our prospective investigation suggests that early (childhood) emotional problems in the general population share genetic risk with schizophrenia, while later (adult) emotional problems also share genetic risk with MDD. The results suggest that the genetic architecture of depression/anxiety is not static across development.