CHRM1 and schizophrenia: For example, the combination of oral clozapine and aripiprazole has been brought up in the literature due to its potential to have limited EPS side effects, as well as one of its proposed mechanisms of action for improving cognition in patients with schizophrenia as a potent partial muscarinic acetylcholine receptor M1 (M1) receptor agonist [7,14,15,19,20,21,22].