Segmentation by type classifies compounds according to pharmacologic class and mechanism of action, each comprising distinct sub‑categories that shape the market landscape. Antidepressants dominate with sub‑types such as selective serotonin reuptake inhibitors (SSRIs), serotonin‑norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs); SSRIs alone capture a majority of new‑drug launches. Anxiolytics include benzodiazepines, buspirone, and newer azapirones, with benzodiazepines retaining a sizable share despite safety concerns. Antipsychotics split into typical (first‑generation) and atypical (second‑generation) agents, the latter driving recent growth through improved side‑effect profiles. Mood stabilizers encompass lithium, valproate, and carbamazepine, each targeting bipolar disorder and adjunctive therapy in schizophrenia. Finally, stimulants—methylphenidate and amphetamine derivatives—remain central to ADHD treatment, with extended‑release formulations expanding market penetration. Understanding these sub‑type dynamics is essential for forecasting pipeline activity and competitive positioning within the Mental Disorders Drugs market.