A personality change occurs when someone's thoughts, actions, or feelings change. It is normal for people's personalities to change as they go through and experience new things in life. Nevertheless, personality changes can be a serious problem if they happen suddenly and are caused by outside influences. The side effects of suboxone therapy for treating opioid use disorder have been studied in large-scale clinical trials. Suboxone was reported to cause no personality changes or mood swings in the trials published by the Food and Drug Administration (FDA). When Suboxone is not taken exactly as prescribed, the buprenorphine component can cause opioid withdrawal. Suboxone can sometimes be misinterpreted as being the cause of mood swings, which are symptoms of opioid withdrawal. You should contact your doctor as soon as possible if you start experiencing personality changes or mood swings while taking Suboxone for opioid use disorder so that they can determine the cause. Taking Suboxone changes users' brain chemistry and may affect their behavior if they abruptly stop taking it.