The invention relates to the use of a functional muscarinic M1/M4 receptor agonist such as the functional muscarinic M1/M4 receptor agonist or a pharmaceutically acceptable salt thereof, in particular sabcomeline or a pharmaceutically acceptable salt thereof in for the treatment of cognitive impairment in schizophrenia and to combination therapies for the treatment of cognitive impairment in schizophrenia which the functional muscarinic M1/M4 receptor agonist or a pharmaceutically acceptable salt thereof, in particular sabcomeline or a pharmaceutically acceptable salt thereof and at least one other neuroprotective agent and/or neuroleptic and/or atypical antipsyhcotic agent are administered adjunctively or simultaneously. The invention provides methods of treatment of cognitive impairment in schizophrenia utilising such therapies and such adjunctive or simultaneous therapeutic combination therapies, therapeutic combinations for use therein and pharmaceutical compositions comprising them.