Parkinson's disease
PDParkinson's disease is a progressive neurological disorder caused by loss of dopamine-producing cells in the brain, leading to tremor, slowness and stiffness.
Motor features include a resting tremor that often begins in one hand, slowed movement, muscle rigidity and problems with balance and walking. Non-motor symptoms are also common and can precede diagnosis by years: loss of smell, constipation, acting out dreams during sleep, depression and later changes in thinking. The disease usually appears after sixty, though younger onset occurs, and it affects men somewhat more often than women.
Diagnosis is clinical, based on the pattern of symptoms and a neurological examination, sometimes supported by imaging that measures dopamine transporter activity. Neurologists manage it with dopamine-replacing medications and, in selected cases, deep brain stimulation. Cannabinoids have been studied for motor and non-motor symptoms in small trials, and the evidence is preliminary and mixed.