Mood-stimulating drugs used primarily in the treatment of affective disorders and related conditions. Several monoamine oxidase inhibitors are useful as antidepressants apparently as a long-term consequence of their modulation of catecholamine levels. The tricyclic compounds useful as antidepressive agents (antidepressive agents, tricyclic) also appear to act through brain catecholamine systems. A third group (antidepressive agents, second-generation) is a diverse group of drugs including some that act specifically on serotonergic systems.