Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and impulsivity. There are three main types of ADHD: predominantly inattentive, predominantly hyperactive-impulsive, and combined type. But which one is the least common?
The 3 Types of ADHD
Let’s take a quick look at the key features of the three ADHD types:
Predominantly Inattentive Type
- Difficulty paying attention and staying focused
- Easily distracted
- Forgetful
- Difficulty following instructions
- Lacks attention to detail
Predominantly Hyperactive-Impulsive Type
- Fidgety behavior
- Excessive talking
- Unable to sit still
- Impatient
- Interrupts conversations
Combined Type
- Symptoms of both inattentive and hyperactive-impulsive types
Prevalence of ADHD Types
Many studies have looked at the prevalence rates of the different ADHD types. While rates can vary somewhat based on the study methodology and population, the predominantly inattentive type consistently emerges as the most common. The combined type is generally the second most common, followed by the predominantly hyperactive-impulsive type as the least common.
For example, a systematic review published in 2020 analyzed findings from 102 studies looking at ADHD type prevalence. It found the following mean prevalence rates among children and adolescents:
| ADHD Type | Prevalence |
|---|---|
| Predominantly inattentive | 44.9% |
| Combined type | 31.4% |
| Predominantly hyperactive-impulsive | 23.7% |
The findings were similar when looking specifically at studies focused on North America, with inattentive ADHD being the most common at 46.6%, followed by combined type at 30.8%, and hyperactive-impulsive trailing at 22.6%.
Why Is Hyperactive-Impulsive Type Less Common?
There are a few possible reasons why the predominantly hyperactive-impulsive presentation of ADHD tends to be less common than the other types:
Age-Related Decline in Hyperactivity
Hyperactive and impulsive symptoms tend to decline with age more than inattentive symptoms do. As children with ADHD get older, their hyperactivity often diminishes, whereas attention difficulties usually persist. So the hyperactive-impulsive presentation is more likely to be “outgrown” and may no longer meet diagnostic criteria in adolescence or adulthood.
Changing Diagnostic Criteria
The diagnostic criteria for ADHD have changed over time. In the DSM-IV, published in 1994, there was a greater focus on hyperactive-impulsive symptoms for diagnosing ADHD in general. However, the criteria were updated in the DSM-5 in 2013 to require fewer hyperactivity symptoms and emphasize inattentiveness more.
Possible Underdiagnosis
Some experts believe that predominantly hyperactive-impulsive ADHD is underidentified and underdiagnosed, especially among girls. Girls may exhibit symptoms differently than stereotypical presentations based on boys, such as being more quietly hyperactive.
Diagnosing the Predominantly Hyperactive-Impulsive Type
Despite being less common, getting an accurate diagnosis is still important if hyperactive-impulsive symptoms are significantly impacting a child’s functioning. Here are some key considerations in identifying this type of ADHD:
DSM-5 Criteria
To be diagnosed with predominantly hyperactive-impulsive ADHD under the DSM-5 criteria, the following requirements must be met:
- Six or more hyperactivity-impulsivity symptoms persist for at least 6 months in two or more settings (such as home and school)
- Symptoms were present before age 12
- Symptoms interfere with functioning
- Symptoms are not better explained by another condition
Looking Beyond Hyperactivity
Clinicians should assess for any attention difficulties as well, since many children have a combination of symptoms. There still may be some problems focusing even if they don’t meet full inattentive criteria.
Considering Age and Development
Symptom thresholds may need to be adjusted depending on the child’s age and developmental stage. Toddlers and preschoolers tend to be more hyperactive in general.
Getting Collateral Information
Since hyperactive symptoms can vary a lot depending on the situation, it’s important to get information from multiple sources like parents and teachers.
Treatment for Hyperactive-Impulsive ADHD
Effective treatment approaches for predominantly hyperactive-impulsive ADHD include:
Medication
Stimulant medications like methylphenidate (Ritalin) and amphetamines (Adderall) are usually the first-line pharmacological treatments. They have been shown to reduce hyperactivity, impulsivity and inattention.
Behavioral Interventions
Behavior therapy provided by therapists, psychologists or counselors can teach self-monitoring, organization and social skills. Classroom management and parent training are also helpful.
Educational Accommodations
Individualized education programs (IEPs) or 504 plans can provide accommodations like shortened or alternating assignments, assistance staying focused, and options for movement.
Alternative Therapies
Things like yoga, exercise, art and music therapy may help children with hyperactive symptoms channel their energy and impulses in a positive way.
Coping Strategies for Hyperactive-Impulsive Traits
In addition to formal treatment, utilizing various coping strategies can help minimize the impact of hyperactivity and impulsivity:
- Take frequent movement and sensory breaks
- Fidget toys like stress balls and fidget spinners
- Timers to help with waiting or taking turns
- Calming techniques like breathing exercises
- Positive reinforcement systems
- Remove distractions or adjust seating arrangements
- Provide outlets for creativity and energy
Conclusion
In summary, predominantly hyperactive-impulsive ADHD is consistently shown to be the least common presentation, likely due to age-related declines in hyperactivity, diagnostic criteria changes, and possible underidentification. However, accurately diagnosing this type is still important to get appropriate treatment. A combination of medication, behavioral interventions, school accommodations and coping strategies can help manage hyperactive-impulsive symptoms.