New research shows no increase in the proportion of adults in England with autism or psychotic disorders

The prevalence of autism and psychotic disorders have remained stable over time, while signs of drug dependence have risen, according to new results from a major national study on mental health published by NHS England.

Led by the National Centre for Social Research (NatCen), in collaboration with the University of Leicester and City St George's, University of London, the Adult Psychiatric Morbidity Survey (APMS) provides the official statistics on trends over time in autism, psychotic disorder, bipolar disorder, drug and alcohol dependence. It includes the first estimate of the prevalence of eating disorders in England to be based on clinical examination.

The study also suggests that a higher proportion of adults in England use drugs than official figures have shown. The results from the APMS show that nearly one in five 16- to 24-year-olds reported using an illicit drug in the past year (18.1%).

Use of prescription opioids by people to whom they have not been prescribed, which is a major concern in the United States due to drugs such as fentanyl and oxycodone, has previously been hard to track in the UK due to limited data. However, the survey found that 3.2% of adults reported that they had used prescription opioids that hadn’t been prescribed to them, far higher than those reporting use of heroin (0.7%), suggesting that this kind of opioid use is a distinct and more widespread issue.

The findings from the fifth APMS are based on 6,912 interviews conducted between March 2023 and July 2024 with a large nationally representative sample of adults aged 16 and over, including people who are not using NHS services. It includes assessments of both diagnosed and undiagnosed mental health conditions using validated clinical tools.

Key findings include:

• Autism: Around 1 in 100 adults (0.8%) are autistic, consistent across surveys in 2007, 2014, and 2023/24.
• Psychotic disorder: Prevalence remains below 1% (0.4% in 2023/24), similar to previous years (0.4% in 2007 and 0.7% in 2014).
• Bipolar disorder: Screening rates are stable (2.0% in 2014 and 1.9% in 2023/4).
• Alcohol use: Hazardous alcohol use declined from 26.1% of 16-to-64-year-olds in 2000 to 18.9% in 2023/24.
• Drug dependence: Increased from 3.8% in 2014 to 6.7% in 2023/24, driven mainly by cannabis dependence (up from 2.8% to 5.4%).
• Lack of treatment: Most adults with signs of dependence on alcohol or drugs or who experience moderate risk gambling had never received treatment related specifically to drinking, drug use or gambling (e.g. only one adult in five (21.2%) with drug dependence had ever had drug-related support or treatment).
• Prescription opioid use: 3.1% of men and 3.2% of women have used prescription opioids without a prescription, with the highest rates among 25–34-year-olds.
• Eating disorders: First prevalence estimate based on a clinical examination suggests 1.3% of adults have an eating disorder, although this is likely a conservative estimate.
• Inequalities: Mental health issues remain more common in deprived areas and among those facing debt or unemployment.

Sally McManus, Professor of Social Epidemiology at City St George's, University of London and Senior Research Fellow at the National Centre for Social Research, said:

“We need to take heed of the near doubling this decade in the proportion of adults with signs of cannabis dependence - from 2.8% in 2014 to 5.4% in 2023/4. This is despite no similar rise in the proportion of adults using cannabis (7.2% in 2014, 8.7% in 2023/4). The upward trend in signs of dependence may well reflect increases in cannabis potency.

“Before this study, relatively little was known about the extent to which prescription opioid medications were being used in England by people to whom they had not been prescribed. We found that 3.2% of adults reported non-prescribed use of at least one of buprenorphine, fentanyl, morphine, oxycodone, and tramadol at some point in their life, with the proportion highest in 25 to 34 year olds (4.5%).”

Terry Brugha, Professor of Psychiatry at the University of Leicester, said: “Whilst most people with a psychotic disorder were receiving treatment, it is concerning that most who are autistic were not known to services. The survey shows that one in 100 adults were autistic, similar to findings from previous surveys in 2007 and 2014. Most autistic adults were male, and living in more deprived neighbourhoods is associated with being autistic. The autistic adults identified in our survey were no more likely to use health services for a mental health reason or receive mental health treatment than non-autistic adults. Due to small sample sizes, the presentation of results was constrained. However, initial analysis identified little correspondence between professionally diagnosed autism and ADOS-identified autism. This suggests that important differences may exist between research-identified autistic people and those with a clinical diagnosis of autism.” 

Sarah Morris, Research Director at the National Centre for Social Research, said: “This survey provides a uniquely detailed and long-term view of adult mental health in England. By combining consistent, rigorous methods with a nationally representative sample, we’re able to identify emerging challenges - like rising drug dependence - and confirm areas of stability, including the prevalence of autism and psychotic disorder. These findings are vital for shaping services and policy, and we are deeply grateful to the interviewers at the National Centre for Social Research and the University of Leicester, as well as all the adults who kindly agreed to take part in this important research.”