Unravelling symptom-specific polygenic effects on maternal mental health during the perinatal period and postpartum

ImportancePoor maternal mental health can negatively impact affected individuals and families. While genetic factors are important influences on mental health, few studies have used symptom-level analyses to examine how genetic liability is related to maternal mental health. A symptom-level approach can account for disorder heterogeneity and delineate key associations between genetic liabilities and mental health, improving current understanding of how genetic risk is related to the experience of specific mental health problems.ObjectiveTo examine associations between genetic liabilities to depression, anxiety, neuroticism and positive affect, and maternal mental health phenotypes (i.e., symptoms of anxiety, depression, positive and negative affect) across the perinatal period and first years of motherhood using a network analysis approach. Design, setting, and participantsThree waves of data from the Norwegian Mother, Father and Child Cohort Study (MoBa) were used to assess item-level associations. Sample sizes ranged from 46,537 to 59,308 mothers. Networks were separately estimated for each polygenic score (PGS) and each wave of measurement: at 30 weeks of gestation, 6 months postpartum, and 18 months postpartum. Main outcomes and measuresSymptoms of anxiety and depression experienced in the last two weeks from the Hopkins Symptom Checklist and items measuring positive and negative affect (i.e., components of emotional functioning) in daily life from the Differential Emotions Scale. Four PGSs, indexing genetic liability to depression, anxiety, neuroticism, and positive affect, were included in separate networks.ResultsPGSs exhibited both phenotype-specific associations (e.g., depression PGS linked with hopelessness, anxiety PGS linked with worry) and cross-phenotype (e.g., depression PGS linked with nervousness, positive affect PGS inversely related to anxiety and depressive symptoms) relationships, with partial correlations ranging between r = -0.025 and r = 0.024. Items measuring mental health were strongly interrelated at each wave, in particular within symptom clusters and among emotional functioning items. Some PGS-phenotype associations were consistent (e.g., depression PGS linked with feeling like screaming or banging on something across all waves) and others inconsistent (e.g., anxiety PGS linked with nervousness only at 6 months postpartum) across the perinatal and postpartum periods.Conclusions and relevanceOur findings highlight symptom-level associations between PGSs and maternal mental health, which may be obscured when global measures of mental health (e.g., overall scores) are used. Identifying symptom-specific PGS associations could advance current understanding of aetiological influences on maternal mental health.