The Symptoms and Subtypes

Updated: Jun 20

ADHD is often referred to as a single condition, but it actually has three different subtypes which affect patients differently, and varying levels of severity in each of these subtypes. There are three main symptom categories in which all observable behaviors caused by ADHD are grouped: inattention, hyperactivity, and impulsivity.

The DSM 5 lists the characteristics of inattention as:

  • Often failing to give close attention to details or makes 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 fails to finish schoolwork, chores, or duties in the workplace such as losing focus or getting side-tracked.

  • Often having trouble organizing tasks and activities.

  • Often avoiding or showing dislike or reluctance to do tasks that require mental effort over a long period of time, such as schoolwork or homework.

  • Often losing things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).

  • Often being easily distracted

  • Often being forgetful in daily activities.

The characteristics of hyperactivity and impulsivity are listed as:

  • Often fidgeting with or tapping hands or feet, or squirming in a seat.

  • Often leaving a seat in situations when remaining seated is expected.

  • Often running about or climbing in situations where it is not appropriate (adolescents or adults may be limited to feeling restless).

  • Often being unable to play or take part in leisure activities quietly.

  • Often being “on the go” or acting as if “driven by a motor”.

  • Often talking excessively.

  • Often blurting out an answer before a question has been completed.

  • Often having trouble waiting their turn.

  • Often interrupting or intruding on others (e.g., butting into conversations or games)

For each of these categories of symptoms, more than 5 must be present to diagnose ADHD in children under 16, and more than 6 to diagnose adults and teens over 17. The following criteria must also be met:

  • Several inattentive or hyperactive-impulsive symptoms were present before age 12 years.

  • Several symptoms are present in two or more settings, (such as at home, school or work; with friends or relatives; in other activities).

  • There is clear evidence that the symptoms interfere with, or reduce the quality of, social, school, or work functioning.

  • The symptoms are not better explained by another mental disorder (such as a mood disorder, anxiety disorder, dissociative disorder, or a personality disorder). The symptoms do not happen only during the course of schizophrenia or another psychotic disorder.

Patients usually meet the number of criteria for one category but not the other, leading to a diagnosis as either predominantly hyperactive/impulsive (ADHD-HI) or predominantly inattentive (ADHD-I). If there is a roughly equal distribution of characteristics across the categories, ADHD combined-type (ADHD-C) is diagnosed. An interesting thing about the type of ADHD is that it can actually change. The brain can re-wire over time due to normal developmental changes and neuroplasticity, and because ADHD is primarily a neurological disorder, the severity and types of symptoms can change too. This means that some people experience fewer symptoms as they get older, or that the presentation of their symptoms may change. For example, someone might be diagnosed with ADHD-HI might later be diagnosed with ADHD-I as their symptoms change.

The type of ADHD I have is predominantly inattentive, and my symptoms mostly manifest as an inability to focus on things that don't interest me or are monotonous, compulsive procrastination, and issues with time management, planning, and organization. I also have some hyperactive symptoms, such as a habit of fidgeting, impulsively touching random things without thinking, and shifting around in my seat a lot, but I've noticed these happening less often over time.


There are three main symptom categories of ADHD listed in the DSM 5: hyperactivity, impulsiveness, and inattention. Some people have more of one symptom type than the other and are diagnosed with one of three types of ADHD. The symptoms and their severity can also change over time.


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