Half of all mental health conditions begin before age fifteen
A meta-analysis of 192 epidemiological studies of age at onset
Reviewed by Sian Trombley, CCCFounder, Thrive Family Company
Strong confidence
Source citation
Solmi M., Radua J., Olivola M., Croce E., Soardo L., Salazar de Pablo G., et al. (2021). Age at onset of mental disorders worldwide: large-scale meta-analysis of 192 epidemiological studies. Molecular Psychiatry. https://doi.org/10.1038/s41380-021-01161-7
Published 1 January 2021 · Added to Thrive 26 July 2026 · Reviewed 26 July 2026
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If mental health difficulties mostly begin in childhood, then childhood is where support should be concentrated.
Published research findings
The study
Solmi and colleagues pooled 192 epidemiological studies to estimate age at onset across diagnoses worldwide.
What researchers examined
Peak and median ages of onset for major categories of mental disorder.
What they found
The peak age of onset was 14.5 years, with roughly a third of conditions beginning before fourteen and about half before eighteen. Anxiety and neurodevelopmental conditions began earliest.
Thrive editorial interpretation
What this may mean for families
Early recognition is not overreaction. It aligns with when these conditions actually start.
What this doesn't tell us
Important limitations
Retrospective onset reporting and varied diagnostic systems across studies.
Evidence confidence describes how much weight this study's design can carry — not how strongly the finding applies to any individual child or family.
Therapist perspective — Thrive interpretation, not a finding of the study
Therapist Perspective
Noticing early and acting calmly is the opposite of pathologising a child.
Practical family considerations
Early attention matches when difficulties actually begin.
This research summary is educational and does not replace individualized medical, psychological or therapeutic advice.
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Therapy for young people works — most reliably for anxiety, least for depression
2017 · Meta-analysis
Strong confidence
Why it matters
Realistic expectations help. Therapy is likely to help, unlikely to be transformative on its own, and works best alongside changes at home and school.