How Does Understimulation Lead to ADHD Hyperfocus? 

People with ADHD often describe two extremes of focus: mental fog during routine tasks and intense absorption when something sparks their interest. According to NICE NG87 and the Royal College of Psychiatrists (CR235), ADHD involves differences in how the brain regulates attention and reward, particularly under low-stimulation conditions. When the brain’s dopamine and arousal levels drop, focus drifts. When stimulation rises, attention can lock in too tightly, producing hyperfocus. 

The Role of Understimulation and Dopamine 

Neuroscience research shows that people with ADHD typically have lower tonic dopamine, which means less baseline motivation and alertness. This under-arousal triggers a search for stimulation, novelty, or reward to lift dopamine levels. When a highly engaging activity appears, a phasic dopamine surge occurs, activating brain regions such as the prefrontal cortex and striatum and shifting attention into overdrive. This process explains why boredom can quickly turn into deep, sustained focus on tasks that feel rewarding or urgent. 

Brain Networks and Arousal Theories 

Models such as the Optimal Stimulation Theory and the Cognitive Energetic Model describe ADHD as a condition of fluctuating neural arousal. During boredom, the default mode network (DMN) dominates, encouraging day-dreaming or mind-wandering. Once a rewarding or high-interest task is found, the task-positive network and salience network take over, helping concentration but often making it hard to disengage. Researchers note that this pattern is more stimulus-driven than the controlled “flow” experienced by neurotypical individuals. 

Managing Focus in Low-Stimulation Settings 

According to NHS and NICE guidance, stimulant medications such as methylphenidate can stabilise dopamine signalling, improving attention consistency and reducing extreme swings between distraction and hyperfocus. Non-drug strategies include alternating task types, using brief breaks, and adding sensory or cognitive stimulation to maintain alertness without tipping into over-focus. 

Reassuring Takeaway 

Understimulation is a key driver of both boredom and hyperfocus in ADHD. When dopamine is low, the brain seeks stimulation; when a task provides strong reward, focus narrows intensely. Finding balance through structure, movement, and tailored treatment helps maintain steady attention and reduce frustration. You can also book a medication review with ADHD Certify, a UK-based service offering NICE-aligned ADHD assessments and ongoing care.