Regressive Autism: what it is and how to spot it

What is Regressive Autism


Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder that has several sub-conditions, one of which is known as ‘Regressive Autism’.  It is less spoken about and perhaps less recognized, but is what I am seeing with increasing frequency in my clinic.

This type of autism is characterized by a deterioration in  language skills, social interaction and motor skills.  Typically, the child has met all the developmental milestones up to around the age of 18 months to 2 years. Then someone close to the child, usually a parent or care-giver, begins to notice that their child talks less, makes less eye contact, has abdominal discomfort, irregular bowel habits and worsening behaviour.  Because this often happens around the age of 2-4 years, it can be hard to distinguish some of the traits from what is commonly referred to as ‘terrible twos’, or maybe it is put down to a change in environment if the child starts play school or nursery.  There are often lots of potential legitimate reasons for the change in behaviour, which may be why it has been spoken about so little until now.

In recent years, there has been an increase in the awareness and diagnosis of regressive autism, leading to more research and understanding of this unique form of the disorder. However, it remains a poorly understood and often misdiagnosed condition, leaving many families struggling to find answers and support for their loved ones. In this article, I’ll write a little about my experiences as a clinician with various families so that we can delve deeper into the world of regressive autism, exploring what it is, how to spot it, and its impact on individuals and families.

What is Regressive Autism?

Regressive Autism, also known as Autism Regression or Late-Onset Autism, is a subtype of Autism Spectrum Disorder (ASD) characterized by a significant loss of previously acquired skills or developmental milestones. Unlike some other forms of autism where symptoms are present from early childhood, regression in autism typically occurs between the ages of 15 to 30 months. This sudden regression can involve a decline in language and social skills, as well as the emergence of repetitive behaviors and restricted interests.  Identifying the signs of regression and seeking early intervention is crucial in order to provide appropriate support and therapeutic interventions for individuals with regressive autism.  In the UK it is also extremely helpful to get a diagnosis before your child starts school so that you can have the practical support in place before the September start.

Early signs and red flags

Children with regressive autism may exhibit early signs and red flags that indicate a potential regression in their development. These signs can vary from child to child but may include a loss of previously acquired language skills, social engagement and play skills. Parents and caregivers may notice a decline in eye contact, a lack of response to their name being called and a decrease in social interaction. Other red flags may include repetitive behaviour such as hand-flapping or toe-walking and an increased sensitivity to sensory stimuli.

Early warning signs

  1. Loss of previously acquired developmental milestones
  2. Decreased social interaction and communication
  3. Repetitive behaviour patterns and obsessions
  4. Lack of interest in pretend play
  5. Difficulty with transitions and changes in routine
  6. Sensory sensitivities or aversions
  7. Digestive issues such as abdominal pain, constipation, diarrhoea.
  8. Restricted palate (becoming increasingly picky at meal times) and being sensitive to colour, texture and sound of food (EG crunching noise).

Importance of early detection

Early detection of regressive autism is of utmost importance in order to provide timely intervention and support for affected children. Identifying the signs and symptoms as soon as possible allows for early intervention services to be initiated, ideally before your child starts school.  Having a care plan in place for the beginning of term can make a very significant difference.  For example, many children with ASD get easilly overwhelmed in large crowds, so it could be as simple as allowing them to leave or arrive at school ten minutes before the bell goes. Perhaps allowances can also be made for meal times.  I know my children struggled with tremendous stress in the hustle and bustle of the school canteen and it often led to indigestion or simply not eating properly at all.  Nutrition for Autism is a vital topic that is so important, I cannot discuss it here, because there is so much to be said about autism and a gluten-free-casein-free diet, gut function in people with ASD and how it differs from others due to genetic differences, the gut-brain axis and much more. 

If your child’s speech is deteriorating, you may notice an increase in lability, mood swings, aggressive behaviour, tantrums or lack of focus and attention.  This can all be linked to an inability to express himself or herself and the frustration that arises because of that.  Many of the families I have worked with tell me that their child became aggressive towards other people in school or nursery, so any intervention that can help ease their frustration, pain or aggression is vital in helping that child to remain in – or get access to – mainstream education. 

Social interaction is a core skill that children learn when they first go to nursery or school, but for an autistic child, social interactions can be extremely stressful, although that is not true for everyone!  However, in early years it is important to recognize challenges in this area and find ways of addressing it.  If an autistic child gets overwhelmed in social situations, they may lash out, which will lead to them being removed from the company of other children for the safety of all concerned.  There are various solutions to this and in my clinic I focus on the physiological changes in people with ASD and the impact of food on neurotransmitters, for example, but a whole team of other healthcare professionals will be involved in addressing behavioural and speech issues.  It is complex, but with early diagnosis, outcomes can be very significantly altered.

How functional medicine for ASD can help a child with regressive autism

Functional medicine for autism offers a holistic approach to address the underlying factors contributing to the symptoms and challenges experienced by children with regressive autism. Unlike traditional medicine which often focuses solely on symptom management, functional medicine aims to identify and treat the root causes of autism spectrum disorder. By considering factors such as gut health, immune function, nutritional deficiencies and genetic predispositions, I develop personalized treatment plans tailored to the unique needs of each family I work with. These treatment plans include dietary changes, targeted supplementation, detoxification support and lifestyle modifications.

At Barefoot Medicine, Simone has developed a protocol called the D.A.R.I.N.G.Approach to Healthcare.  This acronym stands for Discover (get tothe root cause), Analyze (non-invasive functional testing of body systems), Report (get the lab results back and combine them with the discovery consultations to get a whole picture of how we got here).  I is Integrate where we find a way to realistically integrate lifestyle medicine, functional nutrition, targeted supplementation and other therapies into your daily routines.  N is for Nourish where we use your food as medicine, so you know which diets you need to eat or avoid.  Finally G is the Guide to Sustained Recovery which is your go-to place at the end of our time working together so you know how you can help yourself going forward.  At the moment this is a document but by July 2024 this will be an online community that contains courses, videos, ebooks, crib sheets and group workshops.

Support and Resources for Families

Book a free 15-minute consultation with Simone to discuss your family’s situation and find out how functional medicine for autism could help to improve your health and wellbeing.

The Autism Directory


What is regressive autism and how does it differ from other forms of autism?

Regressive autism is a subtype where children develop typically for a period and then lose previously acquired skills, such as language or social interactions. This differs from other forms of autism, where symptoms are present from early childhood and do not involve a loss of skills. The regression usually occurs between 18 months to 3 years of age, leading to a rapid decline in abilities. Despite this setback, children with regressive autism can still make progress with early intervention and support.

What tests can be done for autism?

Functional testing is extremely beneficial not for diagnosis, but to understand the biochemical environment that is impacting neurotransmitters.  The main tests to consider include Organic Acid Tests, Gut function test, mycotoxin test, glyphosate test, metabolic test and environmental and toxic elements hair strand test.

What are some common signs or symptoms of regressive autism that parents or caregivers should look out for?

Common signs of regressive autism include loss of communication skills, social withdrawal, repetitive behaviours, loss of previously acquired skills, decreased eye contact, difficulty with changes in routine, and unusual sensitivity to sensory stimuli. Parents or caregivers should also look out for signs such as delays in reaching developmental milestones, lack of interest in playing with peers, and unusual motor movements. You also need to look out for signs of abdominal discomfort, bowel habit changes, especially constipation and decreasing interest in a variety of foods.

At what age does regression typically occur in children with regressive autism?

Regressive autism typically occurs between the ages of 15 and 30 months, with the average age being around 18 months. During this period, children with regressive autism may start to lose previously acquired language and social skills, as well as exhibit other developmental delays. As discussed, though, sometimes it is hard to know whether there are other more prosaic contributions to changes in behaviour.

Are there any specific risk factors or genetic markers associated with regressive autism?

Whilst there are no specific markers regarding autism, there are genetic SNPs that are commonly present in people with ASD that can lead to certain behaviour and certain digestive issues.

How can functional medicine help children with regressive autism improve their communication and social skills?

Functional medicine may be able to help children with regressive autism improve their communication and social skills by addressing underlying issues such as gut health, nutrient deficiencies, and inflammation that may be contributing to their symptoms. By focusing on individualized treatment plans tailored to each child’s unique needs, we aim to optimize overall health and support cognitive development, potentially leading to improvements in communication and social interactions. This holistic approach can help identify and address root causes of the condition, providing a more comprehensive and personalized approach to treatment by helping your child to use their food as medicine and be the best version of themselves.

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