Parkinson's disease is a brain disorder characterized by the death of dopamine-producing neurons, which leads to a progressive loss of motor control and various nonmotor symptoms. Although symptoms typically begin after age 60, a small percentage of people may experience early onset, and the disease affects men and women differently in terms of progression and mortality.

Parkinson's disease leads to both motor symptoms (such as tremors, bradykinesia, and muscle stiffness) and nonmotor symptoms (including depression, fatigue, and cognitive decline). These symptoms start subtly and progressively worsen over time, which increases the risk of falls and injuries.

Parkinson's disease is diagnosed primarily through symptoms, medical history, and a physical exam, with a focus on identifying parkinsonism, which includes bradykinesia and either muscle rigidity or resting tremors. Although there are currently no definitive tests for the disease, imaging techniques may be used in inconclusive cases, and family medical history is also considered due to its relevance in diagnosis.

The main medical treatments for Parkinson's disease focus on increasing dopamine levels, and common options include levodopa, MAO-B inhibitors, and dopamine agonists. Additionally, anticholinergic drugs can help reduce tremors and muscle stiffness, and amantadine may be used to suppress involuntary movements.

Several supplements have been studied for their potential therapeutic effects on Parkinson's disease and target mechanisms such as oxidative stress, inflammation, and mitochondrial dysfunction. Notable supplements include vitamin C, vitamin E, vitamin D, coenzyme Q10, creatine, omega-3 fatty acids, curcumin, whey protein, and N-acetylcysteine.

Diet plays a significant role in Parkinson's disease risk, and certain foods are associated with either increased risk (such as dairy and fried foods) or decreased risk (such as coffee, fresh fruits, vegetables, and adherence to a Mediterranean diet). Although research suggests that healthier dietary patterns may lower risk, cohort studies on this relationship have been inconclusive.

For individuals who do not respond to conventional therapies for Parkinson's disease, deep brain stimulation can be used to alleviate motor symptoms. Additionally, treatments that target the thalamus, such as MRI-guided focused ultrasound or thalamotomy, may be used for tremor-predominant Parkinson's disease, along with occupational therapy to enhance daily functioning.

Parkinson's disease is caused by the death of dopamine-producing neurons in the brain's substantia nigra pars compacta region, which leads to reduced dopamine levels and results in motor symptoms such as tremors and impaired coordination. Additionally, other brain areas are affected, which may contribute to nonmotor symptoms.