Most people think of ADHD (Attention-Deficit/Hyperactivity Disorder) as a condition characterized by distractibility, impulsivity, forgetfulness, and hyperactivity. However, after analyzing thousands of SPECT (Single Photon Emission Computed Tomography) brain scans, Dr. Daniel Amen proposed that ADHD is not a single disorder. Instead, he suggests that several distinct brain activity patterns can produce ADHD-like symptoms.
Two of the most discussed patterns in Dr. Amen's model are Classical ADHD and Overfocused ADHD. At first glance, these two types may seem completely opposite. One individual appears unable to focus on anything, while the other appears unable to stop focusing on certain thoughts, worries, or interests.
Yet according to Dr. Amen, both patterns share important underlying features while differing in specific brain activity patterns, particularly within the Prefrontal Cortex and Anterior Cingulate Cortex (ACC).
Understanding these similarities and differences can help explain why ADHD looks very different from one person to another.
Understanding SPECT Brain Imaging
Unlike traditional MRI scans that primarily show brain anatomy, SPECT scans measure blood flow and activity levels throughout the brain.
Areas receiving greater blood flow appear more active, while areas with reduced blood flow appear less active.
Dr. Amen used these scans to identify patterns that he believes correspond to different ADHD presentations. While these subtypes are not officially recognized by the DSM-5, they provide an interesting framework for understanding variations in attention, behavior, and emotional regulation.
What Is Classical ADHD?
According to Dr. Amen, Classical ADHD is the pattern most people recognize.
Common symptoms include:
Distractibility
Impulsivity
Hyperactivity
Poor organization
Forgetfulness
Difficulty completing tasks
Restlessness
Difficulty sustaining attention
These individuals often struggle to remain focused on boring or repetitive activities.
They may start many projects but finish very few.
What Is Overfocused ADHD?
Overfocused ADHD appears very different.
Instead of struggling to maintain attention, individuals often struggle to shift attention.
Common symptoms include:
Obsessive thoughts
Excessive worrying
Perfectionism
Mental rigidity
Holding grudges
Difficulty adapting to change
Persistent negative thinking
Hyperfocus
The challenge is not a lack of attention.
The challenge is excessive persistence of attention.
The brain becomes locked onto particular thoughts, worries, routines, or interests.
Similarity 1: Both Show Prefrontal Cortex Dysfunction
One of the most important similarities involves the Prefrontal Cortex (PFC).
The Prefrontal Cortex controls:
Attention regulation
Impulse control
Planning
Organization
Working memory
Decision-making
Dr. Amen's SPECT scans suggest that both Classical ADHD and Overfocused ADHD show reduced efficiency in this region.
When the Prefrontal Cortex is underactive:
Attention becomes difficult to regulate.
Organization suffers.
Working memory becomes less efficient.
Task completion becomes challenging.
This shared feature helps explain why both groups can meet diagnostic criteria for ADHD despite looking very different behaviorally.
Similarity 2: Dopamine Dysregulation
Both Classical ADHD and Overfocused ADHD appear to involve abnormalities in Dopamine Pathways.
Dopamine is a neurotransmitter involved in:
Motivation
Reward
Attention
Learning
Goal-directed behavior
Low dopamine activity may contribute to:
Difficulty sustaining effort
Reduced motivation
Inconsistent attention
Reward-seeking behaviors
This may explain why both groups often respond to treatments that influence dopamine signaling.
Similarity 3: Executive Function Problems
Both forms frequently exhibit difficulties with Executive Functions.
Executive functions include:
Planning
Prioritizing
Time management
Task initiation
Self-monitoring
Emotional regulation
Although the symptoms appear different, both groups often struggle with managing daily responsibilities effectively.
Similarity 4: Hyperfocus Can Occur in Both
Many people assume hyperfocus only occurs in Overfocused ADHD.
However, individuals with Classical ADHD may also experience Hyperfocus.
Both groups may become deeply absorbed in:
Video games
Research topics
Creative projects
Personal interests
Social media
The difference lies in frequency and flexibility.
People with Overfocused ADHD tend to become stuck more consistently.
The Biggest Difference: The Anterior Cingulate Cortex
The most significant distinction in Dr. Amen's SPECT studies involves the Anterior Cingulate Cortex (ACC).
The ACC functions as the brain's "gear shifter."
It helps regulate:
Cognitive flexibility
Attention shifting
Adaptability
Error detection
Conflict monitoring
Classical ADHD
In Classical ADHD, the ACC generally does not show excessive activity.
The main issue is underactivation of attention-control regions.
The brain struggles to maintain focus.
Attention drifts from one stimulus to another.
Overfocused ADHD
In Overfocused ADHD, Dr. Amen reports increased activity within the ACC.
This overactivity may cause the brain to become stuck.
Instead of attention wandering, attention refuses to move.
As a result:
Thoughts become repetitive.
Worries become persistent.
Arguments continue longer.
Perfectionism develops.
Mental flexibility decreases.
This ACC overactivity is considered one of the defining features of Overfocused ADHD in Amen's model.
Difference in Attention Style
Classical ADHD: Attention Deficit
People with Classical ADHD often describe their minds as:
Scattered
Distracted
Restless
Chaotic
Attention jumps rapidly between multiple stimuli.
External events easily interrupt concentration.
Overfocused ADHD: Attention Persistence
People with Overfocused ADHD often describe their minds as:
Stuck
Rigid
Repetitive
Obsessive
Attention remains locked on one subject for extended periods.
The challenge becomes disengaging rather than concentrating.
Difference in Emotional Regulation
Classical ADHD
Emotions often appear quickly and intensely.
However, emotional reactions may fade relatively quickly.
The person moves on to the next stimulus.
Overfocused ADHD
Emotions tend to linger.
Individuals may replay emotional events repeatedly.
Anger, embarrassment, disappointment, or frustration can persist for days, weeks, or even years.
This phenomenon is sometimes called Emotional Sticking.
Difference in Thinking Patterns
Classical ADHD Thinking
Common thought patterns include:
Rapid topic switching
Frequent distractions
Incomplete thoughts
Mental wandering
Overfocused ADHD Thinking
Common thought patterns include:
Rumination
Obsessive analysis
Excessive worrying
Repetitive mental loops
Persistent focus on problems
The brain repeatedly revisits the same thoughts.
Difference in Relationships
Classical ADHD
Relationship difficulties often arise from:
Forgetfulness
Interrupting conversations
Impulsivity
Poor listening
Overfocused ADHD
Relationship difficulties often arise from:
Holding grudges
Excessive arguing
Difficulty forgiving
Rigidity
Need for control
The person may struggle to let go of disagreements.
Difference in Response to Change
Classical ADHD
Individuals often seek novelty and stimulation.
New experiences can be exciting and rewarding.
Overfocused ADHD
Individuals frequently prefer predictability.
Unexpected changes may trigger stress or frustration.
Routine provides a sense of control.
SPECT Scan Comparison
According to Dr. Amen's observations:
Classical ADHD
SPECT scans commonly show:
Reduced activity in the Prefrontal Cortex
Reduced activity during concentration tasks
Difficulty activating attention-control systems
Overfocused ADHD
SPECT scans commonly show:
Reduced Prefrontal Cortex efficiency
Increased Anterior Cingulate Cortex activity
Greater difficulty shifting cognitive states
Increased mental rigidity
The overactive ACC becomes the major distinguishing feature.
Strengths of Classical ADHD
Many individuals demonstrate:
Creativity
Spontaneity
Innovation
Curiosity
Risk-taking ability
High energy
Their minds often generate numerous ideas rapidly.
Strengths of Overfocused ADHD
Individuals frequently exhibit:
Persistence
Determination
Loyalty
Deep expertise
Attention to detail
Long-term commitment
Their minds excel at sustained concentration and follow-through.
Important Scientific Perspective
While Dr. Amen's SPECT-based ADHD subtypes are widely discussed, it is important to recognize that they are not officially accepted diagnostic categories within mainstream psychiatry.
The DSM-5 currently recognizes:
Predominantly Inattentive Presentation
Predominantly Hyperactive-Impulsive Presentation
Combined Presentation
Nevertheless, Amen's model offers a useful way to understand why two people diagnosed with ADHD can display remarkably different symptoms.
Two Different Paths to Attention Dysregulation
According to Dr. Daniel Amen's SPECT scan studies, Classical ADHD and Overfocused ADHD share important underlying features, including Prefrontal Cortex dysfunction, dopamine dysregulation, and executive function difficulties. However, they differ dramatically in how attention behaves.
In Classical ADHD, attention is difficult to maintain and easily pulled away by distractions. In Overfocused ADHD, attention becomes trapped and difficult to redirect. The key difference appears to involve increased activity within the Anterior Cingulate Cortex, a brain region responsible for cognitive flexibility and shifting attention.
Understanding these differences highlights an important truth about ADHD: attention problems are not always caused by too little focus. Sometimes they result from too much focus that becomes difficult to release. Both patterns can create significant challenges, but both also come with unique strengths that, when properly managed, can become powerful assets in education, work, relationships, and personal growth.
Keywords: Classical ADHD, Overfocused ADHD, Dr Daniel Amen, SPECT Scan ADHD, Anterior Cingulate Cortex, Prefrontal Cortex, ADHD Brain Types, Hyperfocus, Cognitive Rigidity, Dopamine Pathways
Search Description: Compare Classical ADHD and Overfocused ADHD through Dr. Daniel Amen's SPECT scan studies, exploring brain differences, symptoms, and attention patterns.