Characterisation of depressive symptoms in young children with and without attention deficit hyperactivity disorder

Depressive symptoms and attention deficit hyperactivity disorder (ADHD) are prevalent and commonly co-occur in childhood. To assist with early identification of depression in children with ADHD, we aimed to: (1) use factor analysis to determine whether the construct of depression is measured consistently in those with and without ADHD; and (2) determine whether overall depressive symptoms and specific depressive symptoms were elevated in children with ADHD relative to controls. Participants comprised a community-based sample of 179 children with ADHD (51% Combined presentation, 35% Inattentive presentation) and 212 non-ADHD controls aged 6-8 years. Participants were screened for ADHD and underwent a structured diagnostic interview which confirmed ADHD status and assessed depressive symptoms. The factor structure of depressive symptoms was similar, enabling comparisons between the two groups to be made. Eighteen children with ADHD (10%) and three control participants (1%) experienced either MDD or subthreshold MDD. Children with ADHD experienced more depressive symptoms than controls (Cohen's d =1.19, p < 0.001), with the following symptoms elevated in children with ADHD relative to controls: sadness (32% vs. 14%, p < 0.001), irritability (52% vs. 19%, p < 0.001), insomnia (56% vs. 22%, p < 0.001), psychomotor agitation (53% vs. 9%, p < 0.001), feeling bad about oneself (50% vs. 24%, p < 0.001), difficulty concentrating (75% vs. 14%, p < 0.001) and making decisions (56% vs. 17%, p < 0.001). This study provides support for the occurrence of depressive symptoms in children with ADHD as young as six and highlights the importance of early assessment for depressive symptoms in children with ADHD.