A multimodal MRI study of the hippocampus in medication-naive children with ADHD: what connects ADHD and depression?
Jonathan Posner1, Francesco Siciliano1, Zhishun Wang1
1Columbia College of Physicians and Surgeons, New York, NY, United States; New York State Psychiatric Institute, Unit 74, 1051 Riverside Drive, New York, NY 10032, United States.
Insights
Children with attention-deficit/hyperactivity disorder (ADHD) show reduced hippocampal volume and connectivity, linked to increased depression risk. These brain differences may explain why ADHD youth are more prone to developing depression.
Area of Science:
- Neuroscience
- Child Psychology
- Psychiatry
Background:
- Children with ADHD have a higher risk of depression.
- Neurobiological factors linking ADHD and depression are not well understood.
- Hippocampal abnormalities are implicated in depressive disorders.
Purpose of the Study:
- To investigate the relationship between the hippocampus and depressive symptoms in children with ADHD.
- To explore hippocampal volume and functional connectivity in relation to ADHD and depression.
Main Methods:
- Magnetic resonance imaging (MRI) was used to assess hippocampal volume and resting-state functional connectivity.
- The study included 32 medication-naive children with ADHD and 33 healthy controls (ages 6-13).
Main Results:
- Children with ADHD exhibited reduced left hippocampal volumes compared to controls.
- Reduced functional connectivity was observed between the left hippocampus and left orbitofrontal cortex (OFC) in children with ADHD.
- These hippocampal alterations correlated with more severe depressive symptoms, independent of ADHD symptom severity.
Conclusions:
- Preliminary findings suggest hippocampal structural and connectivity anomalies are associated with depression risk in children with ADHD.
- Further longitudinal research is warranted to explore the link between hippocampal abnormalities and mood disorder susceptibility in ADHD youth.
Abstract:
Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for developing depression. The neurobiological substrates that convey this risk remain poorly understood. On the basis of considerable data implicating hippocampal abnormalities in depressive disorders, we aimed to explore the relationship between the hippocampus and levels of depressive symptomatology in ADHD. We used magnetic resonance imaging (MRI) to examine the volumes and resting-state functional connectivity of the hippocampus in a sample of 32 medication naive children with ADHD (ages 6 - 13) and 33 age- and sex-matched healthy control (HC) participants. Compared with the HC participants, the participants with ADHD had (i) reduced volumes of the left hippocampus and (ii) reduced functional connectivity between the left hippocampus and the left orbitofrontal cortex (OFC); these hippocampal effects were associated with more severe depressive symptoms, even after controlling for the severity of inattentive and hyperactive/impulsive symptoms. Altered hippocampal structure and connectivity were not associated with anxiety or more general internalizing symptoms. Though preliminary, these findings suggest that the relationship between hippocampal anomalies and ADHD youth's susceptibility to developing depression and other mood disorders may merit further investigation with follow-up longitudinal research.
