A neuropsychiatrist sits at the overlap of neurology and psychiatry, treating the psychiatric effects of conditions that damage or disrupt the brain. That list runs from epilepsy, traumatic brain injury, Parkinson's disease, multiple sclerosis and Huntington's disease through to brain tumours and dementia, along with functional neurological disorder, where symptoms such as seizures or paralysis are entirely real but are not caused by structural damage to the brain.
Telling apart cause and coincidence
A central part of the work is distinguishing psychiatric symptoms that arise directly from a neurological condition, depression caused by a stroke's effect on brain tissue, for instance, from psychiatric symptoms that happen to sit alongside a neurological condition without being caused by it. That distinction sounds academic but changes treatment considerably: the underlying mechanism determines which medications will help and which might interact badly with treatment already in place for the neurological condition itself.
Prescribing with the whole picture in view
Because many neurological conditions are treated with medications that have their own psychiatric side effects, a neuropsychiatrist prescribes with that full picture in mind rather than treating the mental health symptom in isolation. This makes the specialty a natural point of referral for anyone whose mood, thinking or behaviour has changed following a diagnosis affecting the brain, where a general psychiatric assessment alone might miss what is actually driving the change.