Autism or ADHD? How to know which assessment pathway to consider

At CADS, one of the most common questions we hear is: “We think something is different — but we don’t know if it’s autism, ADHD, or both.” This uncertainty is understandable. Autism and ADHD share many traits that affect communication, emotions, learning, and daily life. Families often feel unsure which assessment to pursue or worry about choosing the wrong path.

This post explores how to recognise the differences and overlaps between autism and ADHD, helping you decide which assessment pathway to consider. Understanding these conditions can guide you toward the right support and improve quality of life.

Understanding Autism and ADHD

Autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are both neurodevelopmental conditions. They affect how the brain processes information, but they do so in different ways.

• Autism primarily affects social communication and behaviour. People with autism may find it hard to understand social cues, prefer routines, and have intense interests.

• ADHD mainly impacts attention, impulse control, and activity levels. People with ADHD often struggle to focus, sit still, or control impulses.

  
  

Despite these differences, many symptoms overlap. For example, both conditions can involve:

• Difficulty concentrating

• Challenges with social interactions

• Emotional regulation issues

• Sensory sensitivities

• Feeling overwhelmed or exhausted after social or work activities

  
  

Because of this overlap, it is common for people to be diagnosed with both autism and ADHD. Research shows that 40 to 70 percent of autistic individuals also meet criteria for ADHD. Similarly, many people assessed for ADHD show autistic traits.

Signs that suggest an Autism Assessment

If you or your child show signs related to social communication and behaviour, an autism assessment might be the right path. Look for:

• Difficulty understanding or using verbal and nonverbal communication

• Challenges in making or keeping friends

• Preference for routines and distress when routines change

• Intense focus on specific interests or hobbies

• Sensory sensitivities such as strong reactions to sounds, lights, or textures

• Difficulty interpreting emotions in self or others

  
  

For example, a young person who struggles to join group conversations, prefers solitary activities, and becomes upset by unexpected changes may benefit from an autism assessment.

Signs that suggest an ADHD Assessment

If attention, impulsivity, and hyperactivity are the main challenges, an ADHD assessment may be more suitable. Watch for:

• Difficulty sustaining attention on tasks or conversations

• Frequent forgetfulness or losing items

• Impulsivity, such as interrupting or acting without thinking

• Restlessness or difficulty sitting still

• Feeling easily bored or distracted

• Struggling to complete tasks or follow instructions

  
  

For instance, a child who cannot stay focused during homework, often interrupts others, and has trouble waiting their turn might be showing signs of ADHD.

When Both Autism and ADHD Are Possible

Because these conditions often co-occur, some people show signs of both. This can make it harder to decide which assessment to pursue first. Examples include:

• A young adult who finds social situations confusing and overwhelming but also struggles with attention and impulsivity

• A child who has sensory sensitivities and rigid routines but also has difficulty concentrating and sitting still in class

  
  

In these cases, it is important to seek a comprehensive assessment that considers both autism and ADHD. Many services can evaluate for both conditions within the same overall process.

How to Choose the Right Assessment Pathway

Choosing the right assessment depends on your main concerns and observations. Here are some steps to help:

• List the main challenges you or your child face daily.

• Note when and where these challenges occur (e.g., school, home, social settings).

• Consider which symptoms cause the most difficulty or distress.

• Talk to professionals such as teachers, doctors, or therapists who know you or your child well.

• Seek an assessment service that offers evaluations for both autism and ADHD if you notice signs of both.

  
  

Remember, there is no wrong door. Getting assessed is the first step toward understanding and support.

Assessment tools and sensory toy on a clinician’s desk ready for evaluation

What to Expect During an Assessment

Assessments for autism and ADHD usually involve:

• Detailed interviews about development, behaviour, and challenges

• Questionnaires completed by the individual, family members, or teachers

• Observations of behaviour in different settings

• Cognitive or psychological testing in some cases

  
  

The process can take several sessions. It aims to build a full picture of strengths and difficulties, not just label a diagnosis.

Why Getting the Right Diagnosis Matters

A clear diagnosis helps in many ways:

• Access to tailored support and interventions

• Better understanding of strengths and challenges

• Improved communication with schools, workplaces, and healthcare providers

• Reduced stress from uncertainty or misdiagnosis

• Connection with communities and resources

  
  

For example, knowing a child has both autism and ADHD can lead to combined strategies that address social and attention differences.

Supporting Yourself or Your Child After Diagnosis

After diagnosis, support can include:

• Therapy focused on understanding social interactions, such as perspective taking, emotional regulation, or executive functioning

• Educational adjustments such as extra time or quiet spaces, and structured interventions

• Supplements or medication for ADHD symptoms if recommended by a doctor

• Sensory tools or strategies to manage sensitivities

• Peer support groups or counselling

  
  

Families often find it helpful to connect with others who share similar experiences.

Choosing between autism and ADHD assessments can feel confusing, but understanding the signs and overlaps helps guide the way. If you notice challenges in social communication, routines, or sensory processing, an autism assessment might be right. If attention, impulsivity, and hyperactivity stand out, consider an ADHD assessment. When a combination of both sets of signs appear, seek a combined evaluation.

The most important step is to seek professional advice and support. There is no wrong door to understanding and helping yourself or your loved one live well.