若年者の反社会的行動と脳全体の構造変化との関連を解明（Antisocial behaviour in young people linked to changes throughout the brain – major global study）

2026-06-17

2026-06-16 バース大学

英国バース大学が主導する国際共同研究チームは、反社会的行動（規則違反、攻撃性、易刺激性など）を示す子どもや若者では、脳全体にわたる広範な構造変化がみられることを明らかにした。研究では、12か国・18集団から集めた5～21歳の約14,000人のMRIデータを解析した。その結果、行動上の問題が深刻になるほど、大脳皮質の厚さや表面積が小さくなり、感情学習や記憶に関与する皮質下領域の容積も減少する傾向が確認された。これらの変化は行為障害（Conduct Disorder）と診断された若者だけでなく、軽度の問題行動を示す群にも認められた。従来は特定の感情処理領域に注目する研究が多かったが、本研究は反社会的行動が脳の広範囲な構造差異と関連することを示した。また、問題行動は「ある・ない」の二分法ではなく連続的なスペクトラムとして捉えるべきであることを支持している。研究者らは、脳構造だけで行動は決定されず、家庭環境や社会環境、トラウマ体験などの要因も重要であると強調しており、早期介入や予防戦略の改善につながる知見として期待している。

＜関連情報＞

ENIGMAにおける18の国際コホートにおける行動問題と脳構造の次元的関連性 Dimensional Associations Between Conduct Problems and Brain Structure Across 18 International Cohorts in ENIGMA

Marlene Staginnus, PhD ∙ Yidian Gao, PhD ∙ Sophie Townend, PhD ∙ … ∙ Esther Walton, PhD ∙ Stephane A. De Brito, PhD ∙ Graeme Fairchild, PhD
Journal of the American Academy of Child & Adolescent Psychiatry Published:March 12, 2026
DOI:https://doi.org/10.1016/j.jaac.2026.03.002

Graphical abstract

Abstract

Objective

Although conduct problems (CPs) are continuously distributed, little is known about how dimensional measures of CPs map onto brain structure. Therefore a large sample was used to comprehensively assess associations between dimensionally measured CPs and brain structure.

Method

T1-weighted structural brain magnetic resonance imaging scans from 14,160 youths (5-21 years old, 46.2% female) across 18 international case-control, community-based, and population-based cohorts were preprocessed using ENIGMA-standardized protocols. Regression models examined associations between CPs and cortical thickness, surface area, and subcortical volumes, adjusting for age, sex, and intracranial volume. Moderation by sex, age, and callous-unemotional traits was also investigated.

Results

Widespread but small (β = −0.02 to −0.07) negative associations were observed between CPs and surface area (total surface area, 23/34 regions), cortical thickness (average thickness, 15/34 regions), and amygdalar and hippocampal volumes. Sex was a key moderator, with many surface area associations limited to boys and some thickness associations limited to girls. Some associations were stronger in younger children and at lower levels of callous-unemotional traits. The impact of adjusting for IQ and other psychopathology varied by outcome (eg, most surface area findings survived IQ adjustment, whereas cortical thickness associations did not).

Conclusion

CPs were associated with subtle, yet widespread, alterations in brain structure. Findings overlapped with differences observed in categorically measured conduct disorder, but novel associations with cortical thickness were identified. This provides further evidence that neuroanatomical differences are not limited to youth with clinically elevated CPs. Our findings have potential implications for neurocognitive models of CPs as they extend beyond the regions highlighted in these models.