Final answer:
The most common side effect of conventional antipsychotic medications is extrapyramidal symptoms (EPS) due to dopamine receptor blockade. These drugs also commonly cause a reduction in affect and interest in the environment, as well as potential sedation and drowsiness.
Step-by-step explanation:
Common Side Effects of Conventional Antipsychotic Medications
The most common side effects associated with conventional antipsychotic medications pertain to their influence on motor functions and their impact on a patient's affect and responsiveness. These manifestations can include extrapyramidal symptoms (EPS) such as tardive dyskinesia, dystonia, and Parkinsonism, which are a direct effect of the drug's action on dopamine pathways. Additionally, patients might experience reduced interest in their environment, diminished affect, and a general slowing down in their responsiveness to stimuli. More severe side effects can mimic symptoms akin to those of Parkinson's disease due to dopamine receptor blockade which affects motor control.
Other common manifestations might be sedation, drowsiness, and with some antipsychotics, effects such as agitation, anxiety, sleeping problems, and gastrointestinal discomfort could occur. While these medications can reduce psychotic symptoms like hallucinations, delusions, and disorganized thinking, their action on dopamine receptors is a double-edged sword, thereby causing the noted side effects.