People taking drugs for mental-health problems often stop taking their medication. It is thought this is, at least partially, due to the side effects of the drugs but the exact relationship between side effects and non-adherence to medication is unclear. An eighteen-month U.S. study of 406 people between 18 and 75 followed them up three months after their admission for depression to see what side effects they had suffered and whether they were still taking their medication. One in four of the patients had stopped taking their drugs. Among the side effects noted only 'change in weight' and 'anxiety' were significant predictors of discontinuation. Experiencing one or more 'extremely' bothersome side effect(s) was associated with a doubling of the risks of discontinuation but side effects less severe than this were not significant predictors. There were no differences among the antidepressants in terms of side effects or discontinuation rates.
Goethe, John W. ... [et al] - Selective serotonin reuptake inhibitor discontinuation : side effects and other factors that influence medication adherence Journal of Clinical Psychopharmacology October 2007, 27(5), 451-458