CHRNA7 and schizophrenia: In one phase II trial, the highly selective α7nAChR full agonist (Ki = 1 nM) TC-5619 at doses of 1–25 mg improved cognitive and negative symptoms in 185 patients with schizophrenia receiving adjunctive quetiapine or risperidone [89], whereas in another phase II trial, TC-5619 at doses of 5 or 20 mg combined with a new-generation antipsychotic (121 patients with schizophrenia in each group) did not improve negative or cognitive symptoms [90].