‘Is it more challenging to treat mental illnesses in autistic individuals than those without autism?’ This might be a common difficulty that many therapists encounter while treating autistic clients with comorbidity. Worldwide, it is estimated that around 1 in 100 of the total population is diagnosed with Autism Spectrum Disorders (ASD) according to the DSM-5 criteria (WHO, 2023). Over 54% of ASD individuals reported co-occurred anxiety, and 47% reported co-occurred depression with a higher level of comorbidity and functional deficits compared with atypical groups without autism (Hossain et al., 2020).
Evidence-based Cognitive Behavioural Therapy (CBT) is considered the gold standard when it comes to treating comorbid disorders in autism. Nevertheless, a recent review of studies found inconsistent results for CBT in reducing symptoms, such as depression and anxiety, among autistic individuals (Menezes et al., 2020). In this case, further investigation is needed to implement more effective CBT interventions that improve comorbid problems in individuals with ASD.
This blog will focus on a mixed-methods study conducted by Trimmer and colleagues (2024) within Improving Access to Psychological Therapies (‘IAPT’ or NHS Talking Therapies Services) in England, utilising low-intensity cognitive behavioural therapy (LICBT) with autism-adapted techniques to explore the effectiveness of improving clinical outcomes. This is the first study that compared whether either group or one-to-one guided self-help LICBT results in a greater decrease in depression and anxiety symptoms. They hoped with the improvement of CBT interventions and autism adaptations to optimise mental outcomes for autistic adults with depression and anxiety.
Treating mental illness in autistic individuals poses unique challenges due to high rates of comorbidity and mixed evidence on the effectiveness of standard therapies like CBT.
Methods
This mixed-method research included a quantitative design to measure the reduction in the severity of co-occurring disorders and compare the effectiveness between two conditions (group or one-to-one) and a qualitative semi-structured interview to understand clients’ opinions towards autism-adapted LICBT.
All participants (n = 84) were recruited from Plymouth Autism Spectrum Service and met inclusion criteria, including being over 18 years old, clinically identified as ASD, and diagnosed with co-existing anxiety and depression with no potential risk. The selection process of one-to-one guided self-help intervention is based on participants’ personal preference and clinical advice (e.g., those who are clinically more suitable for one-to-one modes), with the remainder allocated to group treatment, with a maximum of 10 patients per session. After completing all treatment sessions, 6 participants were invited to the semi-structured interview according to their personal willingness and accessibility.
Three psychological practitioners who received training for autism awareness and practical adaptations delivered both LICBT treatments (one-to-one & group). The self-administered version of the Patient Health Questionnaire (PHQ-9) and Generalised Anxiety Disorder Questionnaire (GAD-7) were employed to assess participants’ mental symptoms before (as baseline) and after completing all LICBT sessions (as clinical outcomes).
The authors conducted a 2×2 factorial ANOVA, including a between-subject variable (treatment: one-to-one and group) and a within-subject variable (time: pre- and post-outcome scores). Subsequently, a thematic analysis was used to represent their qualitative findings.
Results
The following demographics were recorded across groups:
| One-to-one (n) | Group (n) | Qualitative interview (n) | |
| N | 40 | 44 | 6 |
| Gender | 14 Female
25 Male 1 Non-binary |
10 Female
33 Male 1 Non-binary |
1 Female
3 Male 2 Non-binary |
| Ethnicity | 38 White British
2 Other |
44 White British | 6 White British |
| PHQ-9 | 40 | 44 | 6 |
| GAD-7 | 40 | 44 | 6 |
Quantitative findings
The study results exhibited a significant decrease in depression and anxiety symptoms after completing both group and one-to-one LICBT. According to the within-subject analysis, there was a significant effect over time, in which the average scores for anxiety level (i.e., GAD-7) differed before and after treatment (F = 92.34, p <.001, η2 = .134), and the average scores for depression (i.e., PHQ-9) also differed by time (F = 39.86, p <.001, η2 = .060). The effect size of time using a t-test is median-to-large for anxiety scores (d = 0.75) and small-to-median for depression scores (d = 0.48), meaning that the interventions had a noticeable impact over time.
The estimates indicated that there is a significant interaction between time and treatment on both the severity of anxiety (F = 13.78, p = <.001) and depression (F = 8.46, p = .005), suggesting that the effects of LICBT treatment on mental outcomes depended on the treatment type (i.e., group and one-to-one). However, there were no significant differences in reducing depression and anxiety levels between the one-to-one and group conditions, showing that the main effect of the treatment type itself did not contribute to the reduction of symptoms.
Qualitative findings
The semi-structured interview captured participants’ thoughts on their experiences with LICBT, how the intervention favoured them, and how it could be improved. The authors summarised four main themes that expressed participants’ perceptions of treatments.
- Human interaction: In-group social and verbal interaction with others facilitated the function and process of treatment; nevertheless, practitioners sometimes played a negative role.
- Content that stood out: It is vital for clients to feel that they are acquiring useful knowledge and strategies for self-managing by providing self-learning materials, such as booklets and PowerPoint. Linking the conditions to autism and clearly distinguishing the difference between CBT and LICBT may also improve their willingness to participate.
- Structuring treatment: The balance between the treatment content and the time given to the clients to process information needs to be considered when preparing for treatment. The best number of patients in one session was around six.
- Barriers to treatment: Previous experiences with barriers of misconception and prejudice prevented patients from receiving treatment.
Study participants valued social interaction, tailored content, and structured sessions.
Conclusions
This study found the effect of LICBT interventions on decreasing symptoms of mild to moderate mental conditions, illustrating either group or one-to-one treatment is able to improve autism comorbid disorders, such as depression and anxiety. As the initial step in IAPT, LICBT offered guided self-help, psychoeducation, least invasive exposure, less session time, and flexible delivery modes compared with standard CBT. The findings reveal the necessity and feasibility of employing LICBT and autism adaptations for autistic clients with co-occurring disorders in NHS services.
Adapted LICBT may be a feasible and effective approach for reducing comorbid symptoms in autistic individuals.
Strengths and limitations
The current research is the second to explore whether an adapted, low-intensity CBT can reduce co-occurring symptoms in ASD. As other studies either focused on various adapted-autism interventions (Rodgers et al., 2024) or applied low-intensity only to children and adolescents (Ramirez et al., 2020), the present study is well justified and reasonably motivated to examine the effectiveness of LICBT with adaptations in autistic adults with comorbidity. The second strength is its mixed-method design, which provides new insight beyond quantitative statistics into how autistic people feel they can benefit from low-intensity treatments and how some barriers hinder their access to clinical therapies. Evaluating patients’ feedback after completing a course of treatment helps practitioners develop adapted therapies tailored to people with autism to improve accessibility and reduce bias.
However, the first weakness is that the study did not use a randomised and double-blind method. Secondly, the allocation was based on the preferences of clients and practitioners, as well as the availability of resources. Consequently, evaluation of the effectiveness of CBT treatment and the generalisability of the study results are limited as its selection strategy may involve bias. Not to mention that only patients with mild-to-moderate depression and anxiety and no potential risk were included, further restraining the statistical power of detecting the effect of treatments and the generalisability to the wider population (e.g., severely depressed people with suicidal intentions).
In addition, the authors did not include a standard CBT as a comparison group, making it impossible to examine the difference between the efficacy of autism-adapted treatment and typical CBT in decreasing the severity of comorbidity in autism. Thus, it cannot make any suggestion about whether autism-adapted interventions can be more effective than standard CBT. Besides, the inclusion criteria were not clearly evaluated, but possible confounding factors may influence the treatment outcome. For example, Russel et al. (2020) reported adverse events (e.g., residential status) and previous psychiatric history may affect the attendance of LICBT interventions for autistic people. Yet none of these and related factors (e.g., substance use, socioeconomic status) was measured and mentioned in the present study.
The lack of randomisation and control group in this study limits the generalisability and strength of its conclusions.
Implication for practice
Recent evidence found that CBT has been less effective for autistic people than typical individuals with mental conditions, and the current NHS attendance rate underrepresented the true prevalence of autism comorbidity suggested (El Baou et al., 2023). In this case, providing adaptations to standard CBT content may improve the efficacy of psychological interventions. The authors exhibited an alternative option that lowered depression and anxiety levels among autistic people in this study. It highlights the possibility in real-life clinical settings that autistic patients may be referred to low-intensity sessions rather than being identified as not suitable for IAPT. It also suggests the need to offer autistic patients stepped care as well as receive the least intrusive treatment in NHS healthcare services. Actions and policy changes for healthcare systems to open and improve access to LICBT for autistic groups may be warranted, but more research is needed.
What is more, people with autism hold negative opinions toward CBT and therapists, which reduces their motivation to seek intervention from clinical services. Therefore, it is necessary for all practitioners to be equipped with autism awareness, minimising the negative perceptions and barriers from autistic patients. In practice, it would be desirable to include autism-related content and link autism with other comorbid disorders while introducing CBT techniques. To facilitate effectiveness, therapists should make adjustments according to feedback from the previous sessions, ensuring that adaptations and cognitive techniques are applicable to autistic clients.
Future research should consider conducting an RCT with a larger sample size to assess the usefulness of LICBT in adults with autism having co-occurring mental difficulties. Instead of using PHQ-9 and GAD-7, which have no specified internal consistency and validity in investigating autistic populations, it would be reliable to employ psychometric measures validated in autistic samples, such as the Beck Depression Inventory-II (Gotham et al., 2015).
Clinicians should receive autism-specific training to reduce bias and improve therapeutic relationships, helping autistic clients feel better understood and more willing to engage in therapy.
Statements of interest
None to declare.
King’s MSc in Mental Health Studies
This blog has been written by a student on the Mental Health Studies MSc at King’s College London. A full list of blogs by King’s MSc students from can be found here, and you can follow the Mental Health Studies MSc team on Twitter.
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Links
Primary paper
Trimmer, H., Heintz, S., & Williams, S. (2024). Adapting low-intensity cognitive behavioural therapy for autistic adults: lessons from Plymouth’s NHS Talking Therapies and Autism Spectrum Service. Cognitive Behaviour Therapist, 17.
Other references
El Baou, C., Bell, G., Saunders, R., Buckman, J. E. J., Mandy, W., Dagnan, D., O’Nions, E., Pender, R., Clements, H., Pilling, S., Richards, M., John, A., & Stott, J. (2023). 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. The Lancet. Psychiatry, 10(12), 944–954.
Gotham, K., Unruh, K., & Lord, C. (2015). Depression and its measurement in verbal adolescents and adults with autism spectrum disorder. Autism, 19(4), 491–504.
Hossain, M. M., Khan, N., Sultana, A., Ma, P., McKyer, E. L. J., Ahmed, H. U., & Purohit, N. (2020). Prevalence of comorbid psychiatric disorders among people with autism spectrum disorder: An umbrella review of systematic reviews and meta-analyses. Psychiatry Research, 287, 112922-.
Menezes, M., Harkins, C., Robinson, M. F., & Mazurek, M. O. (2020). Treatment of Depression in Individuals with Autism Spectrum Disorder: A Systematic Review. Research in Autism Spectrum Disorders, 78, 101639-.
Ramirez, A. C., Grebe, S. C., McNeel, M. M., Limon, D. L., Schneider, S. C., Berry, L. N., Goin-Kochel, R. P., Cepeda, S. L., Voigt, R. G., Salloum, A., & Storch, E. A. (2020). Parent-led, stepped-care cognitive-behavioral therapy for youth with autism and co-occurring anxiety: study rationale and method. Brazilian Journal of Psychiatry, 42(6), 638–645.
Rodgers, J., Brice, S., Welsh, P., Ingham, B., Wilson, C., Evans, G., Steele, K., Cropper, E., Le Couteur, A., Freeston, M., & Parr, J. R. (2024). A Pilot Randomised Control Trial Exploring the Feasibility and Acceptability of Delivering a Personalised Modular Psychological Intervention for Anxiety Experienced by Autistic Adults: Personalised Anxiety Treatment-Autism (PAT-A). Journal of Autism and Developmental Disorders, 54(11), 4045–4060.
Russell, A., Gaunt, D. M., Cooper, K., Barton, S., Horwood, J., Kessler, D., Metcalfe, C., Ensum, I., Ingham, B., Parr, J. R., Rai, D., & Wiles, N. (2020). The feasibility of low-intensity psychological therapy for depression co-occurring with autism in adults: The Autism Depression Trial (ADEPT) – a pilot randomised controlled trial. Autism : The International Journal of Research and Practice, 24(6), 1360–1372.
