Three types of adhd
Pro Research Analysisby 
Searched over 200M research papers
Understanding the Three Types of ADHD: Predominantly Inattentive, Hyperactive-Impulsive, and Combined
Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), categorizes ADHD into three distinct subtypes: predominantly inattentive type (ADHD-I), predominantly hyperactive-impulsive type (ADHD-HI), and combined type (ADHD-C) .
Predominantly Inattentive Type (ADHD-I)
Characteristics and Prevalence
The predominantly inattentive type (ADHD-I) is marked by significant inattention without the hyperactive and impulsive behaviors that characterize the other subtypes. Children with ADHD-I often struggle with sustaining attention, following through on tasks, and organizing activities . This subtype is the most common among both boys and girls, with a higher prevalence in boys.
Impairments and Challenges
Individuals with ADHD-I typically face academic and cognitive challenges, including difficulties with information processing and executive functions . They are often perceived as daydreamers or slow workers, which can lead to underachievement in school and social settings.
Predominantly Hyperactive-Impulsive Type (ADHD-HI)
Characteristics and Prevalence
The predominantly hyperactive-impulsive type (ADHD-HI) is characterized by excessive fidgeting, restlessness, and impulsive actions. This subtype is less common than ADHD-I and ADHD-C and is more frequently observed in younger children .
Impairments and Challenges
Children with ADHD-HI often exhibit disruptive behaviors that can lead to social and academic difficulties. They may struggle with sitting still, waiting their turn, and controlling their impulses, which can result in conflicts with peers and authority figures . This subtype is also associated with a higher frequency of anxiety disorders and lower quality of life, particularly in females.
Combined Type (ADHD-C)
Characteristics and Prevalence
The combined type (ADHD-C) includes symptoms of both inattention and hyperactivity-impulsivity. It is the most severe and impairing subtype, often leading to significant challenges across multiple domains of functioning .
Impairments and Challenges
Children with ADHD-C are typically the most impaired, facing substantial difficulties in academic performance, social interactions, and family dynamics . They exhibit a higher prevalence of externalizing behavior problems and are more likely to disrupt family activities and schoolwork. This subtype is also the most commonly studied in treatment trials, highlighting its clinical significance.
Validity and Diagnostic Considerations
Diagnostic Validity
Research supports the validity of distinguishing between inattention and hyperactivity-impulsivity symptoms, but the long-term stability of the subtypes is questionable . The combined subtype is generally considered more reliable than the other two subtypes, although the hyperactive-impulsive subtype shows minimal evidence of validity after early childhood .
Alternative Models
Some researchers advocate for a dimensional approach to ADHD diagnosis, suggesting that the subtypes may not represent distinct entities but rather variations in symptom severity . This perspective is supported by findings that ADHD subtypes do not significantly differ in certain neuropsychological measures, such as EEG complexity.
Conclusion
ADHD is a complex disorder with three primary subtypes: predominantly inattentive, hyperactive-impulsive, and combined. Each subtype presents unique challenges and impairments, with the combined type being the most severe. While the DSM-IV subtypes provide a useful framework for understanding ADHD, ongoing research suggests that a dimensional approach may offer a more accurate representation of the disorder's spectrum. Understanding these subtypes is crucial for effective diagnosis, treatment, and support for individuals with ADHD.
Sources and full results
Most relevant research papers on this topic