Severe mental disorders are associated with increased risk of metabolic dysfunction. Identifying those subgroups at higher risk may help to inform more effective early intervention. The objective of this study was to compare metabolic profiles across three proposed pathophysiological subtypes of common mood disorders (‘hyperarousal-anxious depression’, ‘circadian-bipolar spectrum’ and ‘neurodevelopmental-psychosis’).

751 young people (aged 16–25 years; mean age 19.67±2.69) were recruited from early intervention mental health services between 2004 and 2024 and assigned to two mood disorder subgroups (hyperarousal-anxious depression (n=656) and circadian-bipolar spectrum (n=95)). We conducted cross-sectional assessments and between-group comparisons of metabolic and immune risk factors. Immune-metabolic markers included body mass index (BMI), fasting glucose (FG), fasting insulin, Homeostasis Model Assessment-Insulin Resistance (HOMA2-IR), C reactive protein and blood lipids.

Individuals in the circadian-bipolar spectrum subgroup had significantly elevated FG (F=5.75, p=0.04), HOMA2-IR (F=4.86, p=0.03) and triglycerides (F=4.98, p=0.03) as compared with those in the hyperarousal-anxious depression subgroup. As the larger hyperarousal-anxious depression subgroup is the most generic type, and weight gain is also a characteristic of the circadian-bipolar subgroup, we then differentiated those with the hyperarousal-anxious subtype on the basis of low versus high BMI (2 vs ≥25 kg/m², respectively). The ‘circadian-bipolar’ group had higher FG, FI and HOMA2-IR than those in the hyperarousal-anxious-depression group with low BMI.

Circadian disturbance may be driving increased rates of metabolic dysfunction among youth with emerging mood disorders, while increased BMI also remains a key determinant. Implications for assessment and early interventions are discussed.