Introduction

Autistic spectrum disorder (ASD) and attention deficit hyperactivity disorder are different disorders but you can be diagnosed with both disorders together. Both autistic spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) occur when your genes and environment affect your brain development. Autistic spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) usually appear in childhood but can continue into adulthood.

What is the difference between ASD and ADHD?

In autistic spectrum disorder (ASD) you find it hard to communicate with other people and do the same things over and over.

In attention deficit hyperactivity disorder (ADHD) you find it hard to sustain attention and become restless and impulsive.

Can you have both ASD and ADHD?

You can be diagnosed with both autistic spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). More than half of people who have been diagnosed with autistic spectrum disorder (ASD) also have symptoms of attention deficit hyperactivity disorder (ADHD).

What are the symptoms of ASD in adults?

Social communication behaviors

• Little or inconsistent eye contact
• No or slow response
• Difficulties with the back and forth of conversation
• Talk for a long time about your favourite subject without noticing that others are not interested or giving them a chance to respond
• Have facial expressions, movements, and gestures that do not match your words
• Have an unusual voice tone that may sound sing-song or flat and robot-like
• Difficulties in understanding another person’s point of view or actions
• Difficulties in making friends

Restrictive/repetitive behaviors:

• Repeating certain behaviors for example repeating words or phrases
• Becoming upset by slight changes in your routine
• Being more sensitive or less sensitive than other people to sensory input, such as light, sound, clothing, or temperature

Other symptoms

• Sleep problems
• Able to learn things in detail and remember information for long periods
• Strong visual and auditory learner
• Good at math, science, music, or art

What are the symptoms of ADHD in adults?

You may have symptoms of inattention and/or hyperactivity-impulsivity.

Inattention

• Miss details and make mistakes at work, or during other activities
• Find it hard to sustain attention during play or tasks, such as conversations, or lectures
• You do not seem to listen when someone speaks directly to you
• Have difficulty organizing tasks and activities, doing tasks in sequence, keeping materials and belongings in order, managing time, and meeting deadlines
• Lose things necessary for tasks or activities, such as school supplies, pencils, books, tools, wallets, keys, paperwork, eyeglasses, and cell phones
• Be easily distracted by unrelated thoughts or stimuli
• Be forgetful in daily activities, such as returning calls, and keeping appointments

Hyperactivity-impulsivity

• Fidget and squirm while seated
• Leave your seats in situations when you shouldn’t, such as in your work office
• Talk excessively
• Answer questions before they are fully asked, or speak without waiting for a turn in a conversation
• Have difficulty waiting one’s turn Interrupt or intrude on others, for example in conversations, games, or activities

Adults with undiagnosed ADHD may have a history of poor academic performance, problems at work, or difficult or failed relationships. ADHD symptoms can change over time as a person ages.

How is ASD diagnosed in adults?

To diagnose autistic spectrum disorder (ASD) your doctor will ask you about social communication, repetitive behaviours, and restricted interests. Your doctor may also ask your family about your early childhood.

How is ADHD diagnosed in adults?

The symptoms of ADHD need to have been present before age 12. To diagnose adults with attention deficit hyperactivity disorder (ADHD) they must experience at least five persistent symptoms of inattention and/or five persistent symptoms of hyperactivity-impulsivity. These symptoms must be experienced in two or more settings (for example at home and work) and interfere with daily life.

How is ASD treated?

Autistic spectrum disorder (ASD) is usually treated with medications and behavioural therapy. 

Medications that are used to treat ASD include:

• Selective serotonin reuptake inhibitors such as fluoxetine
• Antipsychotics such as Aripiprazole
• Stimulants such as methylphenidate. These medications stimulate your brain to improve your brain function such as concentration and memory

How is ADHD treated?

Attention deficit hyperactivity disorder (ADHD) in adults is usually treated with both medications and cognitive behavioural therapy.

Medications that are used to treat ADHD include:

• Stimulants such as methylphenidate. These medications stimulate your brain to improve your brain function such as concentration and memory.
• Non-stimulant such as atomoxetine or viloxazine. These medications may take 4–6 weeks to reach their full efficacy.
• Antidepressants such as bupropion or tricyclic antidepressants. These medications are usually used to treat depression. But these medications can also be used to treat ADHD if stimulants and non-stimulants are ineffective or can’t be used. 

Implications of a Late Diagnosis

Adults with untreated ASD or ADHD may suffer from depression and anxiety. They may also experience higher rates of unemployment and report poorer physical and mental health outcomes compared to those diagnosed and treated in childhood.

Summary

You can be diagnosed with both autistic spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).

To diagnose autistic spectrum disorder (ASD) your doctor will ask you about social communication, repetitive behaviours, and restricted interests. 

To diagnose adults with attention deficit hyperactivity disorder (ADHD) they must experience at least five persistent symptoms of inattention and/or five persistent symptoms of hyperactivity-impulsivity. These symptoms must be experienced in two or more settings (for example at home and work) and interfere with daily life.

Autistic spectrum disorder (ASD) is usually treated with medications and behavioural therapy. Medications that are used to treat ASD include selective serotonin reuptake inhibitors, antipsychotics, and stimulants.

Attention deficit hyperactivity disorder (ADHD) in adults is usually treated with both medications and cognitive behavioural therapy. Medications that are used to treat ADHD include stimulants, non-stimulants, and antidepressants.