Final answer:
In drug-induced Parkinsonism, muscle rigidity can develop rapidly, often within days to weeks following the initiation of the related medication, due to a decrease or blockage of dopamine function.
Step-by-step explanation:
In drug-induced Parkinsonism, rigidity can develop within days to weeks. Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopamine-producing neurons in the substantia nigra, a region of the midbrain. Common symptoms include tremor, muscle rigidity, bradykinesia, and postural instability. These motor symptoms are attributed to the reduction of dopaminergic innervation in the basal ganglia.
Additionally, cognitive decline and emotional disturbances such as depression may accompany the physical symptoms. Drug-induced Parkinsonism mimics the symptoms of Parkinson's disease, often due to medications that deplete dopamine or block dopamine receptors. The onset of symptoms can occur rapidly after the start of the drug therapy, leading to noticeable rigidity and other Parkinsonian symptoms in a relatively short time frame.