Understanding the 3 Functional Levels of Autism
September 29, 2023
by AutismSTEP
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Children in the autism spectrum demonstrate different patterns of strengths and weaknesses. By understanding their functional level, parents and caregivers can make informed decisions in developing an effective and sustainable support system. The level that a person is assigned reflects how much outside assistance they are likely to need in their daily life.
For instance, Level 1 screening tools have been developed to identify children at risk for ASD. These tools show statistically significant results in adequately detecting autism in the 14-26 months range. Meanwhile, support for level 3 autism includes the same therapies as level 2, but with more intensive and individualised support.
Moreover, children with ASD often struggle to learn functional skills, which are crucial in improving their quality of life. Therefore, by determining their functional level, specialists can prescribe appropriate measures based on the individual’s unique needs. These measures include ABA therapy, which can help people with autism learn new skills, improve communication, and manage challenging behaviours.
When should children be screened for autism?
The three functional levels of autism are defined in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) as follows:
Level 1: Requiring Support

Individuals with this level of autism have mild symptoms and require some support in social communication and restricted, repetitive behaviours. They may have difficulty initiating conversations, responding as expected, and maintaining interest in a conversation.
Level 1 Signs & Symptoms
- Difficulty initiating conversations with others
- Responding as others would expect
- Maintaining interest in the conversation
- Understanding or using nonverbal communication, including facial expression
Level 2: Requiring Substantial Support

People with this level of autism have moderate symptoms and require substantial support in social communication and restricted, repetitive behaviours. They may have limited speech and difficulty with social interaction.
Level 2 Signs & Symptoms
- Challenges in verbal and nonverbal communication
- Reduced or abnormal responses to social cues
- Using fewer words or noticeably different speech
- Missing nonverbal communication cues like facial expressions
- Exhibiting atypical social behaviour, like not responding or walking away during a conversation
- Difficulty switching between tasks, staying organised, and planning
Level 3: Requiring Very Substantial Support

If your child has this level of autism, they are likely to have severe symptoms and require very substantial support in social communication and restricted, repetitive behaviours. They may be nonverbal or have limited speech, have extreme difficulty with inflexible behaviour, and exhibit marked inflexibility of behaviour.
Level 3 Signs & Symptoms
- Nonverbal or limited speech
- Extreme difficulty with inflexible behaviour
- Marked inflexibility of behaviour
- Severe aggression or self-injurious behaviour
- Over or under-sensitivity to particular stimulations from sense, smell, and touch
- Behavioural characteristics such as rocking, echolalia, spinning things, or other behaviours and often struggle with unexpected events.
What is ABA therapy?
Applied Behavior Analysis (ABA) therapy is a scientifically validated approach to understanding behaviour and how it is affected by the environment. Regarded as a medically necessary treatment for people with autism, ABA therapy aims to reinforce desired behaviours in individuals with autism and related developmental disorders.
The therapy is designed to help individuals learn new skills and reduce problematic behaviours. ABA therapy programs involve therapists, or registered behaviour technicians (RBTs), who are trained and supervised by a Board Certified Behavior Analyst (BCBA).
These therapists work directly with children and adults with autism to practise skills and work toward individual goals prescribed by the BCBA. ABA therapy can help increase language and communication skills, improve attention, focus, social skills, memory, and academics, and address challenging behaviours in people with ASD.
How long does ABA therapy usually last?
The duration of ABA therapy can vary depending on the individual’s needs and progress, as well as the type of program they are enrolled in. The therapy plan is determined through an evaluation, and the hours can be naturally reduced or increased as needed.
Focused ABA Treatment, for instance, typically consists of 10-25 hours of one-on-one direct therapy and/or group therapy (for social goals) per week. Meanwhile, Comprehensive ABA Treatment is usually 26-40 hours of one-on-one direct therapy each week.
The average child in the spectrum will receive anywhere between 10-30 per week or longer for intense programs. However, clinical studies suggest that providing ABA therapy for an average of 30-40 hours per week over an extended time can potentially lead to visible improvements.
With ABA therapy, parents should expect their child to receive between 40 and 120 hours in any given month, for roughly 2-3 years of intensive therapy followed by 2-3 more years of a focused approach.
How is progress measured in ABA therapy?
Formal progress assessments are conducted every three to six months throughout the child’s ABA therapy program. During the initial stages of ABA therapy, an evaluation will be performed by a Board Certified Behavior Analyst.
The BCBA will supervise the child’s treatment, which gives them ample opportunity to observe the child’s progress directly. Additionally, the registered behaviour technician will work with the child directly over the weeks and months, implementing each step of the treatment plan.
In turn, the BCBA will write updated reports and evaluations at least every three to six months while maintaining a consistent progress discussion with the parents or caregivers.
Where can you find support for ASD in Singapore
Here at AutismSTEP, we offer custom, research-based therapy to help children with autism unlock their true potential. We deliver a holistic and personalised therapy program spearheaded by our internationally licensed therapists who are well equipped to bring about lifelong improvements to add value to your families’ lives.
To assist you in determining the best therapy for your child, we invite you to book a consultation with us or reach out at +65 6456 9950.
