Recent clinical studies have shown that agonists at
muscarinic acetylcholine receptors effectively reduce
schizophrenia symptoms. It is thus conceivable that, for the first time, a second substance class of procholinergic
antipsychotics could become established alongside the usual antidopaminergic
antipsychotics. In addition, various basic science studies suggest that there may be a subgroup of
schizophrenia in which hypofunction of
muscarinic acetylcholine receptors is of etiological importance. This could represent a major opportunity for individualized treatment of
schizophrenia if markers can be identified that predict response to procholinergic vs. antidopaminergic interventions. In this perspective, non-response to antidopaminergic
antipsychotics, specific symptom patterns like
visual hallucinations and strong disorganization, the presence of
antimuscarinic antibodies, ERP markers such as mismatch negativity, and radiotracers are presented as possible in vivo markers of
muscarinic deficit and thus potentially of response to procholinergic
therapeutics. Finally, open questions and further research steps are outlined.