A 2026 meta-analysis of 50 observational studies estimated that 33% of people with neurofibromatosis type 1 (NF1) have attention-deficit/hyperactivity disorder (ADHD). The pooled estimate came from 29 studies and had a 95% confidence interval of 26% to 40%.
The figure is substantially higher than the general-population estimate of about 3.4% cited for children and teenagers. But the review also emphasized that the 33% figure should not be treated as a precise rate for every NF1 population. The individual studies differed considerably in their methods, participants and findings.
What the review estimated
Across the included research, the pooled estimates for people with NF1 were:
- ADHD: 33%
- Depression: 13%
- Anxiety: 12%
- Autism spectrum disorder: 11%
- Any seizures: 11%
- Epilepsy: 9%
- Intellectual disability: 8%
The review used a random-effects model, which is designed to account for differences between studies. It included research from the Americas, Europe, Asia and Oceania. Study sizes ranged from 24 to 8,579 participants, and reviewers rated 43 of the 50 studies as high quality using a standard checklist for prevalence research.
Why the percentages need context
ADHD prevalence in the individual NF1 studies ranged from 3% to 72%. The statistical prediction interval for a future comparable study was 2% to 73%, showing how much the result could vary across settings. Depression estimates also ranged widely, from 1% to 55%, with a prediction interval of 0% to 63%.
Several factors may contribute to that variation. The studies used mixed diagnostic methods and changing diagnostic definitions, and some research may have included overlapping participants from the same registries or consortia. The meta-analysis also did not include a matched comparison group. Comparisons with the general population therefore relied on estimates from other research rather than a control group assembled for this review.
In practical terms, the pooled numbers are best understood as broad centers of the available evidence—not as a prediction for any one person with NF1. A prevalence estimate also cannot determine which screening tool is best, how often screening should occur, whether screening is cost-effective or whether earlier treatment improves outcomes.
Autism and seizure findings
Autism estimates also differed between studies. An unselected Dutch cohort of 128 children with NF1 found clinical autism in 10.9%. In an international consortium study of 531 children, about 13% scored in the clinical autism range, while another 26% had milder, subclinical traits. A UK population-based study estimated autism in 24.9% of children with NF1, with a 95% confidence interval of 13.1% to 42.1%; a further 20.8% showed a broader autism phenotype.
The pooled estimate for any seizures was 11%, while the estimate for epilepsy was 9%. A previous meta-analysis reported seizure prevalence of 8.1%, with a 95% confidence interval of 5.9% to 10.3%. In that earlier review, 68.5% of people with NF1 and seizures became seizure-free.
What may affect risk
The review examined NF1 microdeletions, in which the whole NF1 gene region is missing. Among microdeletion carriers, the pooled estimate for intellectual disability was 41% and the estimate for ADHD was 45%. The intellectual-disability estimate was based on only two studies involving 86 people.
The researchers said the available data could not show whether microdeletions add ADHD or autism risk beyond the NF1 gene itself. That means these findings should not be used to draw conclusions about an individual’s likely symptoms based solely on genetic status.
The review also found that samples with a higher proportion of women reported more depression. Each one-point increase in the percentage of female participants was linked to an approximately 1.1-point higher depression prevalence in the analyzed studies.
Implications for monitoring
A Danish register study followed 905 people with NF1 and 7,614 population comparisons matched on sex and birth year. It reported higher childhood rates of ADHD, autism and intellectual disability among both sexes with NF1. In early adulthood, women with NF1 had higher rates of unipolar depression, other emotional and behavioral disorders, and severe stress and adjustment disorders.
The same Danish study found similar rates of psychosis, schizophrenia, bipolar disorder and substance use disorders between the NF1 and comparison groups.
The American Academy of Pediatrics guidance cited in the review calls for periodic monitoring of children with NF1, including attention to school and learning difficulties. The new findings support the importance of that broad monitoring approach, while leaving the details of screening schedules and tools to clinical guidance and individual assessment.
AI tools were used to assist with the preparation of this article.
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