The present invention relates to the treatment of psychiatric or neurological disorders in patients in need of pleasant
sensation (lack of pleasure or pursuit of incentive activities) by administering idarsone or a pharmaceutically acceptable salt thereof as a monotherapy or in combination with an
antipsychotic agent. Examples of such psychiatric or neurological disorders include
major depressive disorder, bipolar depression (such as bipolar type I or bipolar type II disorder), post-traumatic stress disorder,
substance use disorder, pleasant
sensation loss related aspects of
schizophrenia (e.g., negative symptoms), and split affective disorder (e.g., with emotional and / or negative symptoms).