Effectiveness of primary care psychological therapy services for treating depression and anxiety in autistic adults in England: a retrospective, matched, observational cohort study of national health-care records

Abstract

Background: Autistic adults report a higher prevalence of anxiety and depression than adults without identified autism but have poorer access to appropriate mental health care. Evidence-based psychological therapies are recommended in treatment guidelines for autistic adults, but no study has investigated their effectiveness in large samples representative of the autistic population accessing routine care. This study aimed to examine therapy outcomes for autistic adults in a primary care service.

Methods: In this retrospective, matched, observational cohort study of national health-care records, we used the MODIFY dataset that used linked electronic health-care records, including national data, for individuals who accessed psychological therapy in primary care in Improving Access to Psychological Therapies (IAPT) services in 211 clinical commissioning group areas in England, UK. All adults aged 18 years or older who had completed a course of IAPT in 2012-19 were eligible, and were propensity score matched (1:1) with a comparison group without identified autism. Exact matching was used, when possible, for a range of sociodemographic factors. Primary outcomes were routine metrics that have been nationally defined and used to evaluate IAPT treatments: reliable improvement, reliable recovery, and reliable deterioration. Secondary outcomes were calculated pre-post treatment changes in scores for Patient Health Questionnaire-9, Generalised Anxiety Disorder Assessment-7, and Work and Social Adjustment Scale measures. Subgroup analyses investigated differential effects across a range of sociodemographic factors.

Findings: Of 2 515 402 adults who completed at least two sessions of IAPT in 2012-19, 8761 had an autism diagnosis (5054 [57·7%] male and 3707 [42·3%] female) and 1 918 504 did not (631 606 [32·9%] male and 1 286 898 [67·0%] female). After propensity score matching, 8593 autistic individuals were matched with an individual in the comparison group. During IAPT treatment, symptoms of depression and generalised anxiety disorder decreased for most autistic adults, but symptoms were less likely to improve in the autism group than in the comparison group (4820 [56·1%] of 8593 autistic adults had reliable improvement vs 5304 [61·7%] of 8593 adults in the matched group; adjusted odds ratio [OR_adj] 0·75, 95% CI 0·70-0·80; p<0·0001) and symptoms were more likely to deteriorate (792 [9·2%] vs 619 [7·2%]; OR_adj 1·34, 1·18-1·48; p<0·0001). In the comparison group, improved outcomes were associated with employment and belonging to a higher socioeconomic deprivation category, but this was not the case for autistic adults.

Interpretation: Evidence-based psychological therapy for depression or anxiety might be effective for autistic adults but less so than for adults without identified autism. Treatment moderators appear different for autistic individuals, so more research is needed to allow for better targeted and personalised care.

Funding: Alzheimer's Society.