30 to 50% of stroke survivors develop post-stroke depression, which is characterized by lethargy, irritability, sleep disturbances, lowered self-esteem and withdrawal. It is most common in those with a stroke affecting the anterior parts of the brain or the basal ganglia, particularly on the left side. Depression can reduce motivation and worsen outcome, but can be treated with social and family support, psychotherapy and, in severe cases, antidepressants. Psychotherapy sessions may have a small effect on improving mood and preventing depression after stroke. Antidepressant medications may be useful for treating depression after stroke but are associated with central nervous system and gastrointestinal adverse events.