Parkinson’s Disease — When Dopamine Runs Low
A neurodegenerative condition where the brain’s “start movement” signal falters — and drive often flattens too.
Parkinson’s disease is caused largely by the progressive loss of dopamine‑producing neurons in the substantia nigra, a region that normally supplies dopamine to the basal ganglia. As those cells die, circuits that initiate and smoothly sequence movement become under‑driven, leading to slowness (bradykinesia), stiffness, tremor and difficulty starting actions.
But Parkinson’s is more than a movement disorder. Because dopamine also helps energise motivation and reward processing, many people experience apathy, fatigue, reduced pleasure and depression. To sufferers, it can feel less like “I don’t want to” and more like “I just can’t get my system to launch.”
Treatment typically combines L-DOPA (a precursor that the brain converts into dopamine) and/or dopamine agonist drugs that stimulate dopamine receptors directly. These can dramatically improve movement and, in some cases, mood — but in a subset of patients, overstimulation of reward circuits can trigger impulse‑control problems like gambling or compulsive shopping, which is why careful monitoring and dose‑tuning matter.
Why It Matters
Understanding Parkinson’s as a dopamine‑system disease — not a character flaw or “old age stiffness” — helps explain both the motor symptoms and the invisible motivational drain, and makes it clearer why medication side effects can show up in behaviour, not just movement.
Closing Line
Parkinson’s is what happens when the brain’s ignition system wears out: the car is still there, but the spark that starts motion and effort has thinned.