Understanding Anxiety in Autistic Children: What Parents and Professionals Need to Know

Anxiety is not a side effect of autism. It is one of the most common co-occurring conditions, affecting an estimated 40 to 50 percent of autistic children and adolescents, compared to roughly 10 to 15 percent of the general paediatric population (1). Yet it remains chronically underdiagnosed and undertreated, partly because anxiety in autistic children often looks different from anxiety in non-autistic children.

How Anxiety Presents Differently in Autism

In textbook descriptions, an anxious child worries verbally, seeks reassurance, and avoids feared situations. Autistic children may do all of these things, but they may also express anxiety in ways that are not immediately recognisable as such:

Increased repetitive behaviours. Stimming, lining up objects, or repeating routines may intensify when a child is anxious. These behaviours are often regulatory, helping the child manage internal distress, rather than being “the problem.”

Meltdowns and shutdowns. What looks like a behavioural outburst or sudden withdrawal may actually be an anxiety response that has exceeded the child’s coping capacity. The trigger may not be obvious to adults, but it is very real to the child.

Rigid insistence on routine. Predictability reduces uncertainty, and uncertainty is a powerful driver of anxiety. A child who becomes intensely distressed by a change in their schedule may be experiencing genuine fear, not “being controlling.”

Demand avoidance. Some anxious autistic children avoid demands of any kind, not because they are oppositional, but because the expectation itself generates unbearable anxiety. This pattern overlaps with what is sometimes called Pathological Demand Avoidance (PDA).

Physical symptoms. Headaches, tummy aches, nausea, and sleep disturbance are common physical manifestations of anxiety. In minimally verbal children, these may present as behaviour change rather than verbal complaint.

Selective mutism. Some autistic children can speak fluently at home but become unable to speak in certain social situations. This is an anxiety-based condition, not a choice (2).

Why Are Autistic Children More Anxious?

Several factors contribute:

Sensory overload. Environments that are manageable for non-autistic children can be genuinely overwhelming for autistic children. The school dining hall, a busy supermarket, or a birthday party may generate a level of sensory input that the nervous system experiences as threatening.

Social unpredictability. Social interactions have an inherent unpredictability that can be extremely stressful when you cannot intuitively read other people’s intentions. Not knowing what someone will say or do next is anxiety-provoking.

Intolerance of uncertainty. Research consistently identifies intolerance of uncertainty as a key cognitive factor in autistic anxiety. Autistic individuals tend to find ambiguous or unpredictable situations more distressing, which makes sense given that their cognitive style often favours clear patterns and rules (3).

Masking. Autistic children who learn to suppress their natural behaviours in social settings (camouflaging or masking) pay a psychological cost. This effort is exhausting and is associated with higher rates of anxiety and depression, particularly in autistic girls (4).

Negative social experiences. Bullying, social exclusion, and repeated failures in social situations create real trauma that feeds anxiety over time.

Assessment Challenges

Standard anxiety questionnaires were not designed for autistic populations and can miss autism-specific presentations. For example, a child who is anxious about unpredictable social situations may not score highly on a scale that asks about “worrying about what others think” because their concern is more fundamental: they cannot predict what will happen at all.

Clinicians with experience in autism should look beyond standard tools and consider:

• Changes in baseline behaviour and routines
• Sleep patterns
• Eating changes
• New or intensified sensory sensitivities
• Physical complaints without a clear medical cause

What Helps

Environmental Adaptations

Before reaching for therapy or medication, consider whether the environment is contributing to the problem:

• Reduce sensory demands where possible. Noise-cancelling headphones, a quiet space to retreat to, dim lighting options.
• Increase predictability. Visual schedules, advance warning of changes, “now and next” boards. The more a child can predict, the less anxious they tend to be.
• Reduce unnecessary social demands. Forced group activities and unexplained social rules create anxiety. Explain the “why” behind expectations.

Cognitive Behavioural Therapy (CBT)

Modified CBT has a reasonable evidence base for autistic children with anxiety. Key modifications include using more visual materials, concrete examples, and longer treatment courses. The NICE recommended approach involves adapting standard CBT to account for the child’s developmental level and cognitive style (5).

Programmes specifically designed for autistic children, such as the Exploring Feelings programme by Tony Attwood or the Facing Your Fears programme, have shown promising results in randomised controlled trials (6).

Medication

For moderate to severe anxiety that does not respond to environmental changes and therapy, medication may be considered. Selective serotonin reuptake inhibitors (SSRIs) such as sertraline and fluoxetine are the most commonly used medications. The evidence base for SSRIs in autistic children with anxiety is not as strong as in the general population, and autistic individuals may be more sensitive to side effects, so starting doses should be low and increases gradual (7).

Medication should always be part of a broader plan that includes environmental support and, where appropriate, therapy.

Physical Activity

This is consistently undervalued. Regular physical activity has been shown to reduce anxiety in autistic children. It does not need to be structured team sports, which may themselves be anxiety-provoking. Walking, swimming, trampolining, or any enjoyable movement can help (8).

What to Avoid

• Forcing exposure without support. Throwing an anxious child into feared situations without preparation or coping strategies is likely to increase anxiety rather than reduce it.
• Dismissing the anxiety. “There’s nothing to worry about” does not help someone whose nervous system has already decided there is.
• Attributing anxiety to “attention-seeking.” Anxious behaviour is communicating distress, not manipulating.
• Over-relying on reassurance. While some reassurance is natural and kind, excessive reassurance-seeking can become a cycle that maintains anxiety. Help the child build coping strategies instead.

When to Seek Professional Help

If anxiety is preventing your child from attending school, participating in activities they previously enjoyed, sleeping, eating, or functioning in daily life, it is time to seek specialist input. Your GP can refer to CAMHS (Child and Adolescent Mental Health Services), and it is worth specifically requesting a clinician with experience in autism, as generic anxiety pathways may not be appropriate.

References

1. van Steensel FJA, Bogels SM, Perrin S. Anxiety disorders in children and adolescents with autistic spectrum disorders: a meta-analysis. Clinical Child and Family Psychology Review. 2011;14(3):302-317.
2. Muris P, Ollendick TH. Selective mutism and its relations to social anxiety disorder and autism spectrum disorder. Clinical Child and Family Psychology Review. 2021;24(2):294-325.
3. Boulter C, et al. Intolerance of uncertainty as a framework for understanding anxiety in children and adolescents with autism spectrum disorders. Journal of Autism and Developmental Disorders. 2014;44(6):1391-1402.
4. Hull L, et al. “Putting on my best normal”: social camouflaging in adults with autism spectrum conditions. Journal of Autism and Developmental Disorders. 2017;47(8):2519-2534.
5. National Institute for Health and Care Excellence. Autism spectrum disorder in under 19s: support and management. Clinical guideline CG170. 2013 (updated 2021).
6. Reaven J, et al. Group cognitive behavior therapy for children with high-functioning autism spectrum disorders and anxiety: a randomized trial. Journal of Child Psychology and Psychiatry. 2012;53(4):410-419.
7. Williams K, et al. Selective serotonin reuptake inhibitors (SSRIs) for autism spectrum disorders. Cochrane Database of Systematic Reviews. 2013;(8):CD004677.
8. Bremer E, Crozier M, Lloyd M. A systematic review of the behavioural outcomes following exercise interventions for children and youth with autism spectrum disorder. Autism. 2016;20(8):899-915.