Attention deficit hyperactivity disorder (ADHD) has a spectrum of symptoms, ranging from mild to severe, that can differ for each person.

ADHD symptoms can vary and depend on the number of symptoms present and the level at which they interfere with everyday functioning.

Doctors will consider this variation when diagnosing someone with ADHD and the type of ADHD they may have.

This article looks at the spectrum of ADHD symptoms, how doctors use this to diagnose someone, and how treatment may vary depending on the severity of the symptoms.

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An older 2016 article suggests the behavioral and cognitive symptoms of ADHD exist on a spectrum of severity. Healthcare professionals will diagnose the condition according to the number and severity of symptoms present in an individual.

According to the charity Children and Adults with Attention-Deficit/Hyperactivity Disorder (CHADD), ADHD symptoms can affect each person differently. The clinical criteria for the condition now account for this variation in symptoms.

To diagnose ADHD and symptom severity, healthcare professionals use criteria from the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR). This classification system diagnoses mental health conditions and disorders affecting the brain.

The DSM-5-TR categorizes ADHD into mild, moderate, or severe. The severity of the condition can change throughout a person’s lifetime.

Mild ADHD vs. severe ADHD

According to CHADD, the DSM-5-TR requires a certain number of symptoms to be present to diagnose ADHD:

  • children require six or more symptoms to be present
  • adolescents over the age of 17 years and adults require at least five symptoms to be present

The number of symptoms present and how they affect a person’s ability to function in everyday situations determines whether ADHD is mild, moderate, or severe.

According to the DSM-5-TR, the following criteria determine the severity of ADHD:

  • Mild: People do not have many other symptoms above the required number for diagnosis. ADHD symptoms only cause minor difficulties in social, school, or work settings.
  • Moderate: Symptoms or functional problems sit between mild and severe.
  • Severe: People have many additional symptoms beyond those necessary for an ADHD diagnosis. Several symptoms are severe or cause significant problems in social, school, or work settings.

The DSM-5-TR categorizes ADHD into three main types:

  • predominantly inattentive
  • predominantly hyperactive-impulsive
  • combination of both the above

Each type of ADHD may also vary in severity, depending on the number of symptoms a person has and how symptoms interfere with functioning.

Predominantly inattentive ADHD

Symptoms of predominantly inattentive ADHD may include:

  • difficulty paying attention
  • appearing not to listen
  • trouble following instructions
  • becoming easily distracted
  • difficulty with organization
  • difficulty with sustained mental effort

Predominantly hyperactive-impulsive ADHD

Symptoms of predominately hyperactive-impulsive ADHD may include:

  • fidgeting, squirming, or difficulty staying seated
  • extreme restlessness, or in children, excessive running and climbing
  • excessive talking and blurting out
  • interrupting others
  • difficulty waiting their turn

If a parent or caregiver thinks a child may have ADHD, they can talk with a doctor about the symptoms present and when they first started.

Healthcare professionals who can make an ADHD diagnosis include mental health professionals, such as a psychiatrist or psychologist, or a primary care provider, such as a pediatrician.

If people think they may have symptoms of ADHD as an adult, they can talk with a doctor or mental health professional.

In adults, ADHD may appear as extreme restlessness, high levels of activity, which may feel tiring to others, or difficulties with time management and organization.

Doctors will use the DSM-5-TR criteria to diagnose ADHD. This diagnosis will include the type of the condition and the severity of its symptoms.

For doctors to diagnose ADHD, a person’s symptoms need to be present for at least 6 months and be inappropriate or disruptive for the standard developmental level of that age group.

Children under the age of 12 years will need to show several symptoms of ADHD to receive a diagnosis.

In adults, at least five ADHD symptoms must be present in at least two different settings, such as home, work, or social. These symptoms must reduce how people are able to function.

Depending on the number of symptoms present and the level at which they interfere with daily life, a doctor will diagnose ADHD as mild, moderate, or severe.

ADHD treatment may vary for each individual and the severity of symptoms, but the main treatments for all types of this condition include behavioral therapies and medications.

According to the Centers for Disease Control and Prevention (CDC), the first-line treatment for children under 6 years is parent training in behavior management. Parents and caregivers will learn strategies to help manage the symptoms of ADHD.

Behavior therapy aims to encourage positive behaviors and reduce problem behaviors. This includes strategies both at home and school and skills training, such as in organization.

Medications for ADHD include stimulants and nonstimulants. Stimulants take effect quickly, while the latter work more slowly but can last up to 24 hours.

In adults, treatment may include:

  • medications
  • psychotherapy, including cognitive behavioral therapy
  • behavioral therapies
  • a combination of all of these approaches

Experts now consider ADHD to be on a spectrum, as each person can experience varying levels of symptom severity. There are also different types of ADHD, which cause different types of symptoms.

When diagnosing ADHD, a doctor will use set criteria to determine the type and severity of ADHD.

Treatments for all types of ADHD may include behavioral therapies and medications. However, the type of treatment a healthcare professional recommends may vary depending on the severity of a person’s symptoms.