New Agents in the Treatment of Psychiatric Disorders: What Innovations and in What Areas of Psychopathology?

Psychiatric disorders are a major cause of illness in the world. Unfortunately, many patients are resistant to treatment and present serious complications. Schizophrenia is refractory to treatment in about one-third of patients. Antidepressants are effective in about half of patients. Suicidal ideation is an increasing issue in patients with mixed features in bipolar disorder (BD). Therefore, there is a need to develop and test new drugs or new indications of available medications for the treatment of psychiatric disorders through evidence-based investigations. This narrative review aims to present the molecules approved by the main drug agencies, the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), from 2018 to date, along with new indications and new formulations of existing medications. We searched PubMed for new drugs approved for schizophrenia, BD, major depressive disorder (MDD), anxiety disorders, and obsessive compulsive disorder (OCD). We evaluated their clinical benefits, safety, and tolerability profiles. Finally, we considered studies on the main molecules that have shown initial evidence of efficacy and are in the process of obtaining approval. Our search suggested that a new antipsychotic, lumateperone, and two drug combinations, olanzapine/samidorphan (OLZ/SAM) and xanomeline/trospium (KarXT), were approved for schizophrenia. In addition, some new methods of administration—monthly risperidone administration, subcutaneous risperidone administration, and transdermal asenapine administration— obtained approval from the main drug agencies. Lumateperone and OLZ/SAM were also approved in BD. Esketamine, a compound that modulates glutamatergic transmission, was approved to treat treatment-resistant depression and acute suicidal ideation. The dextromethorphan/bupropion combination was approved for MDD. Two new agents, brexanolone and zuranolone, were approved for treatment of postpartum depression. On the other hand, no new drugs received approval for anxiety disorders or OCD. In summary, some new psychotropic medications have been developed, in particular with the aim to improve the symptoms of resistant patients and to decrease the incidence of adverse effects. It is necessary to continue testing the effectiveness of new compounds in methodologically rigorous studies.