No increase in prevalence of autism and psychotic disorders

Contrary to public opinion and ‘fake news’ on social media channels, there has been no increase in the prevalence of autism over the last two decades

New results from a major national study on mental health, published by NHS England, provide the official statistics on trends over time in autism, psychotic disorder, bipolar disorder, drug and alcohol dependence, and the first estimate of the prevalence of eating disorder in England to be based on clinical examination.

This survey, one of the most comprehensive sources of data on the prevalence of autism in the general population, is the fifth in a series using comparable and rigorous methods. It is led by the National Centre for Social Research (NatCen), in collaboration with the University of Leicester and City St George's, University of London.

Findings from the Adult Psychiatric Morbidity Survey (APMS) are based on home-based interviews with a large nationally representative sample of adults aged 16 and over, including people who are not using NHS services. While most people with a psychotic disorder were receiving treatment, most adults with autism were not known to health services.

Key findings include:

• The prevalence of autism – based on the 2007, 2014 and 2023/4 surveys combined – was about one adult in a hundred (0.8%). Prevalence has remained stable over time, with no significant differences between the 2007, 2014 and 2023/4 surveys.
• Prevalence of psychotic disorder and of screening positive for bipolar disorder have also remained stable over time. Psychotic disorder was present in less than one in a hundred adults across the 2007 (0.4%), 2014 (0.7%) and 2023/4 (0.4%) surveys, indicating broad stability in England over time. The proportion of adults screening positive for bipolar disorder was similar in 2014 (2.0%) and 2023/4 (1.9%).
• While hazardous alcohol use declined from 26.1% of 16-to-64-year-olds in 2000 to 18.9% in 2023/4, the proportion reporting signs of drug dependence rose (from 3.8% in 2014 to 6.7% in 2023/4). This increase in drug dependence was mostly related to increases in signs of dependence on cannabis, which has nearly doubled this decade (from 2.8% in 2014 to 5.4% in 2023/4). 
• Most adults with signs of dependence on alcohol or drugs or who experience moderate risk gambling had never received treatment related specifically to their drinking, drug use or gambling, and most had not received a related professional diagnosis. For example, one in five (21.2%) adults with signs of drug dependence reported having ever received support or treatment specifically related to their drug use.
• This study provides new insight into the scale of non-prescribed use of prescription opioid medications in England. 3.1% of men and 3.2% of women reported having ever used an opioid medication (buprenorphine, fentanyl, morphine, oxycodone, or tramadol) that had not been prescribed to them. 
• This study provides the first attempt to assess eating disorder prevalence in England’s general population using a detailed clinical examination. An estimated 1.3% of adults were identified with an eating disorder. This may be a conservative estimate, which will be explored further in forthcoming reporting of validation work.

Socioeconomic inequalities in mental health persist. Adults living in the most deprived fifth of areas, those experiencing problems with debt, and those not in employment were more likely to have most of the mental health conditions covered on the survey. 

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.’

Sally McManus, Senior Research Fellow at the National Centre for Social Research and Professor of Social Epidemiology at City St George's, University of London 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 known 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%).’

Dr Zoe Morgan, Research Psychologist at the University of Leicester, said: ‘Our results show that psychotic disorder is a rare condition, affecting less than one in a hundred adults. Previous surveys in 2007 and 2014 reported a similar prevalence for psychotic disorder. Psychotic disorder is associated with deprivation, having a physical health condition, and having a common mental health condition. Also, most people identified by the study as having a psychotic disorder did not think they had the condition. Our findings help us better understand the features of adults with psychotic disorder, and design services to best support these patients who have a high level of clinical need.’

Dr Samuel Tromans, Associate Professor of Psychiatry at the University of Leicester, said: ‘We found that around one in 40 young adults (aged 16-24 years) had an eating disorder in the past year, and around one in 75 adults more generally (aged 16 years or above). Other factors associated with having an eating disorder in the past year included female gender, unemployment, having a limiting physical health condition, and having a common mental health condition, such as depression or anxiety.’

NHS England Digital. Adult Psychiatric Morbidity Survey: Survey of Mental Health and Wellbeing, England, 2023/4. https://digital.nhs.uk/data-and-information/publications/statistical/adult-psychiatric-morbidity-survey/survey-of-mental-health-and-wellbeing-england-2023-24