SIGMAR1 and psychiatric disorder: Therefore, numerous synthetic compounds that bind to Sig-1R, including antidepressants and antipsychotic drugs, have been examined as therapeutic targets for these disorders.7 However, the results of clinical testing have not been satisfactory.8 One possible reason is that the effects of compounds that bind to Sig-1R cannot fully manifest because Sig-1R expression is reduced in the brains of patients with psychiatric diseases.