Extrapyramidal Syndrome Analysis

blocking the majority of these receptors, especially the extrapyramidal syndrome (EPS) which is most bothersome to both patients and doctors putting often an end to treatment.
This inconvenience is explained by the following fact: their antagonizing activity is not directed to the mesolimbic receptors specifically, and ends up acting on all D2 receptors in the brain causing side effects. When they block D2R in the striatal pathway, we have extrapyramidal symptoms resembling those of Parkinson’s disease, and when they block D2R in the tubero-infundibular pathway, they lift all inhibition on prolactin’s release by the pituitary gland, thus causing hyperprolactinemia.
Later came Clozapine and its comrades, known as atypical neuroleptics, which won themselves the “atypical” adjective because they reduce positive symptoms without causing
However, that could be explained by the following notion: These drugs not only block D2R in a more specific way than the previous family, they also have a muscarinic and serotonin-like activity that reduces the side effects caused by D2R general blockade. This effect is due to the fact that the serotoninergic and muscarinic systems cause a release of dopamine, which lessens the side effects by counteracting the excessive blocking of the other pathways. Nevertheless, they do not come without cost. Their most undesired effect is weight gain, metabolic syndrome, diabetes mellitus and cardiovascular disease, which is the first mortality cause among this group of patients.
Hopes for the future
Having talked about the leap made by neuroleptics’ use in the treatment of schizophrenia and their effectiveness on positive symptoms, the problem of negative symptoms remains the same, as both typical and atypical antipsychotics do little in this regard. It is in fact one of the major flaws in the dopamine theory,