Age and sex-related variability in the presentation of generalised anxiety and depression symptoms

Background. Generalised anxiety and depression are extremely prevalent and debilitating. There is evidence for age and sex variability in symptoms of depression, but despite comorbidity it is unclear if this extends to anxiety symptomatology. Studies using questionnaire sum scores typically fail to address this phenotypic complexity. Method. We conducted exploratory and confirmatory factor analyses on GAD-7 (generalised anxiety) and PHQ-9 (depression) items to identify latent factors of anxiety and depression in participants from the Genetic Links to Anxiety and Depression Study (N=35,637; 16-93 years). We assessed age- and sex-related variability in latent factors and individual symptoms using multiple logistic regression. Results. Four factors of mood, worry, motor and somatic symptoms were identified (CFI=0.99, TLI=0.99, RMSEA=0.07, SRMR=0.04). Symptoms of irritability (OR=0.81) were most strongly associated with younger age, and sleep change (OR=1.14) with older age. Males were more likely to report mood and motor symptoms (p<0.001) and females to report somatic symptoms (p<0.001). Conclusion. Significant age and sex variability suggest that classic diagnostic criteria reflect the presentation most commonly seen in younger males. This study provides avenues for diagnostic adaptation and factor-specific interventions.