ADHD and dementia: understanding the differences

Having ADHD does not mean that a person has dementia. A clinician looks at when difficulties began, whether they are changing, and how they affect everyday independence.

ADHD-related forgetfulness often comes from distraction, difficulty organising tasks, or not fully registering information in the first place. The pattern commonly reaches back to childhood or early life, even if ADHD was recognised later.

Dementia involves acquired changes in memory, reasoning, language, orientation, or judgement that progressively interfere with daily life. New trouble managing familiar tasks, getting lost in known places, or repeatedly forgetting recent events warrants assessment. Stress, poor sleep, depression, medication effects, hearing problems, thyroid disorders, and other health issues can also affect thinking, so symptoms need a broad review.

Keep brief notes about the changes, when they started, and examples from home or work. Include current medicines, sleep quality, mood, alcohol use, and any recent illness or head injury. A relative or close friend may help describe changes from the person's previous level of functioning.

Book a GP consultation for new, worsening, or disruptive problems. Assessment may include discussion of lifelong attention patterns, a review of physical and mental health, cognitive tasks, and tests chosen to look for treatable contributors. Continue prescribed ADHD or other medicines unless the prescriber advises a change.

Seek urgent medical help for sudden confusion, a rapid change in alertness, new weakness or facial drooping, trouble speaking, a severe new headache, a seizure, or confusion after a head injury. These changes are not the typical gradual pattern of dementia and may signal a time-sensitive medical problem.

Prompt help is also needed if the person is unsafe at home, is wandering, cannot manage essential medicines, or has thoughts of self-harm.

Ask whether the pattern fits longstanding ADHD, a mood or sleep problem, a medicine effect, or an acquired cognitive change. You can also ask which physical checks or cognitive assessments are appropriate, whether medicines need review, and what changes should trigger an earlier follow-up.