When it comes to neurodivergence, many people are confused about the difference between autism and ADHD and I completely understand why. There are similarities and differences. But on top of that, many people have both—so sometimes people that are talking about one might also unintentionally be referring to the other. It’s easy to get confused.

ADHD is, first and foremost, a disorder of attention, and it involves a persistent pattern of attention-related difficulties that interferes with functioning or development—there are three subtypes, so it can look quite different in different people. It can primarily consist of inattention, hyperactivity, and impulsivity, or a combination of both types of symptoms.

People with ADHD show a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development:

Inattentive symptoms include difficulties staying on task and managing work-related tasks. These can include:

  • Often failing to give close attention to details or making careless mistakes in schoolwork, at work, or with other activities
  • Often having trouble holding attention on tasks or play activities
  • Often not seeming to listen when spoken to directly
  • Often not following through on instructions and failing to finish schoolwork, chores, or duties in the workplace
  • Losing focus
  • Easily getting side-tracked
  • Often having trouble organizing tasks and activities.
  • Often avoiding, disliking, or being reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework)
  • Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones)
  • Being easily distracted
  • Being forgetful in daily activities

Hyperactivity symptoms include impulsive actions, constant movement, and other activity that causes difficulties with staying on task and managing work-related tasks. These can include:

  • Fidgeting
  • Tapping hands or feet
  • Squirming in one’s seat
  • Often leaving one’s seat in situations when remaining seated is expected
  • Often running about or climbing in situations where it is not appropriate
  • Feeling restless
  • Being unable to play or take part in leisure activities quietly
  • Often being “on the go”
  • Acting as if “driven by a motor”
  • Talking excessively
  • Often blurts out an answer before a question has been completed
  • Often having trouble waiting for one’s turn
  • Often interrupting or intruding on others (e.g., butts into conversations or games)

People may have inattentive symptoms, hyperactive symptoms, or both! But symptoms must be disruptive and inappropriate for the person’s developmental level. And this can change over time—or get better as children mature.

In comparison, Autism is primarily associated with social-communication difficulties and restricted, repetitive patterns of behavior, interests, and activities. I know that’s a lot to digest, so I’ll break that down a little further.

Social communication deficits include difficulties with social-emotional reciprocity, nonverbal communication, and relationship skills. These may include:

  • Difficulties with back-and-forth conversation
  • Lack of sharing information with others
  • Lack of sharing emotions with others
  • Unusual effect (display of emotion)
  • Difficulties initiating social contacts
  • Difficulties responding to social requests
  • Unusual combination/use of verbal and nonverbal communication
  • Atypical eye contact
  • Atypical body language
  • Difficulties understanding gestures
  • Atypical use of gestures
  • Lack of facial expressions
  • Lack of nonverbal communication
  • Difficulties shifting behavior to suit different social contexts
  • Difficulties with imaginary play
  • Difficulties with sharing
  • Difficulties making friends
  • Disinterest in peers
  • For children, getting along better with adults than peers
  • Feeling like an alien who is out of place
  • Having to problem-solve social details which seem to come naturally to others

Restricted, repetitive patterns of behavior, interests, or activities may include:

  • Stereotyped motor movements, such as hand flapping, toe-walking, or spinning
  • Repetitive use of objects, such as lining up toys, tapping, or spinning particular toys
  • Repetitive speech patterns, such as echolalia or recurrent use of particular phrases
  • Difficulties with change (extreme distress at small changes)
  • Wanting things to be the same
  • Ritualized patterns of behavior
  • Difficulties with transitions
  • Rigid thinking patterns
  • Very specific greeting rituals
  • Needing to take the same route or eat the same food every day
  • Highly restricted, fixated interests that are abnormal in intensity or focus
  • Strong attachment to or preoccupation with unusual objects
  • Excessively circumscribed or perseverative interests
  • Hyperreactivity to sensory input
  • Hyporeactivity to sensory input
  • Unusual interests in sensory aspects of the environment
  • Apparent indifference to pain/temperature
  • Adverse response to specific sounds or textures
  • Excessive smelling or touching of objects
  • Visual fascination with lights or movement

Autistic symptoms are a little different, in that they can be either current or historical –for this reason, someone who meets criteria for Autism should always meet criteria for Autism, even if their overt characteristics or symptoms are less obvious. There must be some symptoms present in early childhood, but often, it can be difficult to distinguish until an individual’s social demands exceed their capacities (which may happen as the social expectations change, such as in junior high or early adulthood). These are often also masked by learned strategies in older children and adults, so they can be less obvious to the casual observer.

For both Autism and ADHD, there must be some symptoms during childhood, and they must be causing some significant impairment. They are also not setting-specific. If a person has difficulties in just one particular environment but not others, that is likely more representative of difficulties with that setting rather than a developmental disability. Symptoms are long-ranging. If a person starts experiencing acute difficulties and has never before experienced problems, that is unlikely to be one of these conditions. Additionally, for both conditions, the symptoms must not be better explained by another condition. This is where the importance of psychological testing and appropriate evaluation comes in. While addressing symptoms is important, if someone misattributes the cause of those symptoms, it can prevent a person from getting the best treatment available.

While the basis for these conditions differs, sometimes the impacts can be similar. For example, someone with ADHD may have social difficulties due to some of their attention-related behaviors. Constantly running late for social gatherings, forgetting important details in the lives of others, interrupting others, and talking excessively can definitely have a negative impact on social relations. An autistic person with hyperreactivity to sensory input (experiencing lights, sounds, smells, etc. very strongly) may have difficulty attending to a specific task because they are overstimulated by the other sensations. Both can involve the tendency to “hyperfocus” on preferred tasks.

I hope this provides some clarity for people. If you are concerned that either ADHD or Autism might explain some of the things in your or your child’s life, getting a psychological evaluation is a next step. It can help provide insight into how your experiences compare with others and give you the direction and documentation to start getting services that can help.

Dr. Jessica Myszak has had over 11 years of experience performing psychological evaluations with children and adults. She offers both in-person and telehealth evaluations. In addition to seeing clients on the Chicago North Shore, she is able to work with families who reside in Alabama, Arizona, Colorado, Delaware, Florida, Georgia, Kentucky, Illinois, Missouri, Nebraska, New Hampshire, Nevada, Oklahoma, Tennessee, Texas, Utah, Pennsylvania, Virginia, and North Carolina, Washington DC, and Wisconsin! If you are interested in learning more about potentially working with her, you can visit her website here or email her here to get the process started.