Generalized Anxiety Disorders (GAD)
Generalized Anxiety Disorder (GAD), a prevalent condition affecting approximately 5% of the global population, is a mental health disorder characterized by excessive worry and anxiety...
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Parkinson's disease is a neurodegenerative disorder that primarily affects the central nervous system. This condition is linked to the degeneration of nerve cells situated in a deep area of the brain, known as the substantia nigra, which produces dopamine, a neurotransmitter responsible for controlling movements and balance.
Parkinson's disease is classified as a movement disorder due to the emergence of motor symptoms such as resting tremor, slowness and decrease in movements (bradykinesia), rigidity, and instability of posture and/or gait. This degenerative disease evolves slowly and progressively, with the first symptoms appearing when 60-80% of the dopamine-producing cells are damaged.
Parkinson's disease is the second most common neurodegenerative disease, after Alzheimer's. The prevalence of Parkinson's varies globally, with estimates ranging widely.
The average age of onset of Parkinson's disease is approximately 60 years, meaning that the majority of people at risk are between 50 and 70 years old.
The disease is slightly more prevalent in men, with an incidence 1.5-2 times higher than in women. Parkinson's disease rarely manifests before the age of 50.
Parkinson’s disease develops when specific nerve cells in the brain slowly begin to break down and die. These cells are found in a small but important area of the brain called the substantia nigra.
The neurons in the substantia nigra produce a chemical messenger called dopamine (essential for coordinated muscle movements). It acts like a signal between different parts of the brain, especially the striatum, helping to regulate posture, balance, and voluntary movements. This connection between the substantia nigra and the striatum is often referred to as the nigrostriatal pathway.
As Parkinson’s disease progresses, the neurons in the substantia nigra degenerate. As a result, dopamine levels drop, and the brain can no longer properly regulate movement. This leads to tremors, muscle stiffness, slowness of movement (called bradykinesia), and impaired balance and coordination.
A distinctive feature of Parkinson’s disease is the accumulation of Lewy bodies—abnormal clumps of a protein called alpha-synuclein. These protein aggregates are found inside the dying neurons, especially in the substantia nigra, and are believed to disrupt normal cell function, contributing to cell death.
The exact cause of this degeneration is still not fully understood, but it appears to be a combination of genetic predisposition and environmental factors. In some cases, mutations in certain genes are involved. In others, exposure to toxins, oxidative stress, or inflammation may play a role. Aging is also a major risk factor, as the condition is more common in people over the age of 60.
Parkinson's disease primarily affects movement. The most common symptoms include tremors, typically starting in the hands or fingers when at rest, and bradykinesia, which refers to slowness of movement that can make everyday tasks more difficult and time-consuming. Individuals may also experience muscle rigidity, leading to stiffness and reduced range of motion, as well as postural instability, which increases the risk of falls.
Other signs include a shuffling gait, reduced facial expression (often called a “masked face”), and soft or slurred speech. In addition to motor symptoms, Parkinson’s can cause non-motor issues such as sleep disturbances, depression, memory problems, and changes in autonomic functions like digestion and blood pressure regulation. Symptoms vary from person to person and tend to worsen over time.
