Muscarinic Acetylcholine Receptor Activators as Transformative Therapeutics for Schizophrenia

While traditional antipsychotic drugs provide symptomatic relief for positive symptoms in patients with schizophrenia, many patients are refractory to traditional antipsychotics. Furthermore, these medicines are ineffective in treating negative and cognitive symptoms and have serious adverse effects that limit their utility. Traditional antipsychotics act as antagonists or partial agonists of D₂ dopamine receptors, an action that is key to their antipsychotic efficacy and adverse effects. Muscarinic acetylcholine receptor (mAChR) agonists have now emerged as the first truly novel treatments for schizophrenia. This represents a fundamental breakthrough that provides a new treatment option to reduce psychotic symptoms and possibly improve negative and cognitive symptoms in patients with schizophrenia. Mechanistic studies are shedding light on the specific mAChR subtypes involved and the specific neural circuits where mAChR agonists may exert these effects. These studies may pave the way for a new generation of drugs to treat schizophrenia and other neuropsychiatric disorders.