Identify a common side effect of antipsychotic medications.

Tardive dyskinesia is a movement disorder characterized by repetitive, involuntary movements, often caused by long-term use of antipsychotic medications, particularly the typical or first-generation antipsychotics. This side effect arises due to the dopaminergic antagonism that these medications exert in the central nervous system. Over time, this can lead to an upregulation of dopamine receptors, resulting in the abnormal movements that define tardive dyskinesia.

Tardive dyskinesia is particularly concerning because it can be irreversible in some cases, making it a critical aspect of patient monitoring when prescribing antipsychotic medications. Understanding this side effect underscores the importance of weighing the benefits and risks when initiating treatment with antipsychotics, emphasizing the need for ongoing assessment of movement-related symptoms in patients undergoing such therapies.

When considering the other side effects listed, while anxiety, insomnia, and weight gain can occur with antipsychotic medications, they do not have the same level of long-term, irreversible potential as tardive dyskinesia, making the latter a distinctive and significant side effect within this context.