Rosh Psychiatry Board Exam Practice 2025 – Complete Prep Resource

Muscle stiffness, often referred to as "muscle rigidity," is a key indicator of acute dystonia, particularly in patients treated with antipsychotic medications such as haloperidol. Acute dystonia is characterized by sustained or intermittent muscle contractions, abnormal postures, and involuntary movements. In this case, muscle stiffness can manifest as an increased tone in the muscles of the neck, trunk, or limbs, leading to potentially painful and abnormal postures.

This symptom arises due to the blockade of dopamine receptors in the basal ganglia, which disrupts normal motor control. Haloperidol, a first-generation antipsychotic, is known to have a higher propensity for causing extrapyramidal side effects, including acute dystonia, particularly in certain populations or when dosage increases rapidly. Recognizing muscle stiffness as a symptom of acute dystonia is crucial for timely intervention and management to alleviate discomfort and prevent more severe complications.