Research at Duke University Medical Center found that nicotine may improve the symptoms of depression.[46] Nicotine appears to improve ADHD symptoms. Some studies have focused on benefits of nicotine therapy in adults with ADHD.[47]
While acute/initial nicotine intake causes activation of nicotine receptors, chronic low doses of nicotine use leads to desensitisation of nicotine receptors (due to the development of tolerance) and results in an antidepressant effect, with research showing low dose nicotine patches being an effective treatment of major depressive disorder in non-smokers.[48]
Nicotine (in the form of chewing gum or a transdermal patch) has been explored as an experimental treatment for OCD. Small studies show some success, even in otherwise treatment-refractory cases.[49][50][51]