Esmirtazapine, the (S)-(+)-enantiomer of mirtazapine, is currently under development for the treatment of insomnia and menopausal symptoms by the same company that produced mirtazapine.

Mirtazapine's primary use is the treatment of major depressive disorder and other mood disorders.^[3][4]

However, it has also been found useful in alleviating the following conditions and may be prescribed off-label for their treatment:

• Generalized anxiety disorder^[2][5]
• Social anxiety disorder^[6][7]
• Obsessive-compulsive disorder^[6][8]
• Panic disorder^[6][9][10]
• Post-traumatic stress disorder^[6]
• Anorexia nervosa^[11]
• Insomnia^[12][13]
• Nausea/vomiting^[14][15][16]
• Low appetite/underweightness^[17][18][19]
• Itching^[20][21]
• Headaches and migraine^[22][23][15]

Investigational

Mirtazapine has had a solid amount of literature published on its efficacy (or in some cases lack thereof) in the experimental treatment the following conditions:

• Sleep apnea/hypopnea^[24][25]
• Inappropriate sexual behavior and other secondary symptoms of autistic spectrum conditions and other pervasive developmental disorders^{[26][27][28][29]}
• Neuroleptic-induced akathisia^[30][31]
• Drug withdrawal, dependence, and detoxification^{[32][33][34][35][36]}