Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 13 3 2018 06 14 227 229 EN Atefeh zandifar Imam Hossein Hospital, Alborz University of Medical Sciences, Karaj, Iran. Mohammad Reza Mohammadi Psychiatry and Psychology Research Center, Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran. Rahim Badrfam Roozbeh Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2018 03 13 Objective: Selective serotonin reuptake inhibitors (SSRIs) have been the most widely used psychopharmacological agents prescribed for depression worldwide. Some adverse effects of SSRI drugs on central nervous system are insomnia and bruxism. These drugs also affect sleep. Quetiapine is used as adjunctive therapy to antidepressants for the treatment of major depressive disorder (MDD). It is a low- dose dibenzothiazepine with more potent 5-HT2 than D2 receptor-blocking properties that can be used to manage bruxism because of its antagonist effect on the 5-HT2 receptor. Cases: The cases were 5 patients who have recently been treated with SSRIs and presented with bruxism. Low- dose quetiapine (between 25 and 50 mg daily) was prescribed for the patients, and after a few days, they reported no bruxism and continued taking the medication. Conclusion: We found that quetiapine can improve bruxism and mandibular dystonia, which are side effects of SSRIs. https://ijps.tums.ac.ir/index.php/ijps/article/view/1351 https://ijps.tums.ac.ir/index.php/ijps/article/download/1351/743