From the Guidelines
Antipsychotics are medications that work as dopamine D-receptor antagonists or partial agonists, used as the primary pharmacological treatment of schizophrenia.
Definition and Mechanism
- Antipsychotics are used to treat symptoms of schizophrenia, including positive symptoms (hallucinations, delusions, disorganized behavior), negative symptoms (apathy, avolition, anhedonia), and cognitive symptoms (impairment of executive functioning, information processing, and attention) 1.
- These medications have a good effect on reducing positive symptoms, but may not markedly improve negative symptoms or cognitive defects 1.
Types of Antipsychotics
- Typical antipsychotics: also known as conventional neuroleptics, which have a higher risk of extrapyramidal side effects (including tardive dyskinesia) 1.
- Atypical antipsychotics: which are theoretically less likely to cause extrapyramidal side effects, but may still have other potential side effects, such as weight gain, sedation, and increased risk of diabetes and cardiovascular disease 1.
- Clozapine: an atypical antipsychotic with a unique mechanism of action, which is often used for treatment-resistant schizophrenia, but has a higher risk of side effects, such as agranulocytosis and seizures 1.
Treatment Guidelines
- Antipsychotic monotherapy is recommended as the first-line treatment for schizophrenia, with clozapine reserved for treatment-resistant cases 1.
- The choice of medication should be based on the patient's individual response, medical history, and potential side effects 1.
- Regular monitoring of side effects, such as extrapyramidal symptoms, weight gain, and metabolic changes, is essential for patients taking antipsychotics 1.
From the Research
Definition and Classification of Antipsychotics
- Antipsychotic drugs (APDs) are classified into two main categories: typical and atypical, based on their ability to cause extrapyramidal side effects (EPS) 2.
- The distinction between typical and atypical APDs is crucial, as it affects their mechanism of action and side effect profile 2.
- Atypical APDs, such as clozapine, have a unique efficacy profile and are often used as a last-line treatment for treatment-resistant schizophrenia (TRS) 2, 3.
Mechanism of Action and Effects
- Antipsychotic medications work by blocking dopamine D2 receptors in the brain, which helps to alleviate psychotic symptoms 4.
- The blockade of dopamine D2 receptors can also lead to side effects such as extrapyramidal symptoms, weight gain, and sedation 4, 5.
- Atypical APDs may have a more favorable side effect profile compared to typical APDs, with a lower risk of EPS and a reduced risk of tardive dyskinesia 2, 3.
Side Effects and Limitations
- Antipsychotic medications can have significant side effects, including metabolic syndrome, movement disorders, and anticholinergic effects 3, 6, 5.
- The use of anticholinergic drugs to treat EPS can exacerbate cognitive impairment in patients with schizophrenia 6.
- The long-term use of antipsychotic medications can lead to a range of adverse effects, including sedation, sexual dysfunction, and cardiac arrhythmia 5.
Treatment Approaches and Future Directions
- The treatment of schizophrenia and other psychotic disorders often involves a trial-and-error approach, with multiple medications being tried before finding an effective treatment 3.
- Novel treatment approaches, such as targeting dopamine synthesis and storage, and the use of phosphodiesterase inhibitors, may offer new hope for patients with treatment-resistant schizophrenia 4.
- Future developments in antipsychotic treatment may involve personalized medicine techniques, such as pharmacogenetic variants and biomarkers, to tailor treatment to individual patients 3, 4.