Intrusive thoughts are frequently treated with a mix of medication and talk therapy. Serotonin reuptake inhibitors, for example, are OCD medications that assist control serotonin levels and can help minimize intrusive thoughts. Selective serotonin reuptake inhibitors (SSRIs) are the most common type of medication used to treat obsessive-compulsive disorder (OCD). Other types of medication used include tricyclic antidepressants and norepinephrine reuptake inhibitors. It is important to remember that like any other drug, these medications can cause side effects. Common side effects associated with SSRI use include nausea, diarrhea, irritability, and anxiety. People who take benzodiazepines or alcohol while taking an SSRI may experience an increased risk of feeling dizzy or sleepy. If you are taking OCD medications, it is important to tell your doctor if you start experiencing suicidal thoughts or feelings. You should also notify your doctor if the symptoms of OCD worsen while on treatment or if you experience any changes in mood or behavior. Your doctor may need to adjust your dose or switch you to another medication. In addition, like any other form of treatment for OCD, psychotherapy is more effective if combined with medication.