Parkinson’s disease is a disease in which there is a falling off of the numbers of nerve cells in the pigmented cells (substantia nigra) in the brain stem.
The cause is unknown in most people, although very rarely poisons, such as carbon monoxide or repeated head injury (as in punch-drunk syndrome), are responsible. Parkinson’s disease is characterised by a muscular tremor, muscular stiffness and slowing of movement. In addition, some sort of mental changes can be seen in up to 40% of people with Parkinson’s disease.
Depression occurs in about a third of people with Parkinson’s disease – this is not merely a reaction to the diagnosis, or the disability, but is perhaps an integral part of the illness process affecting the brain. It has been suggested that a decrease in brain 5-HT and noradrenaline, which occurs in Parkinson’s disease, can lead on to depression.
The depression that occurs in Parkinson’s disease is usually mild to moderate in its intensity. It responds to the same sort of treatment as any other depressive illness, but the older antidepressants can sometimes cause a seeming worsening in the movement disorder (as a side-effect).
This is removed if the drug is stopped. Newer antidepressants, such as fluoxetine (Prozac), can be easier to tolerate in Parkinson’s disease and can be very effective indeed. In severe depression and Parkinson’s disease, ECT (electroconvulsive therapy) can be used to very good effect.
There may even be a temporary improvement in the symptoms of Parkinson’s disease with this treatment. Unfortunately, this improvement is not sustained.
