Depression and fatigue are common symptoms of multiple sclerosis and are the primary determinants of impaired quality of life in this demyelinating neurological disease. The twelve-month prevalence of major depression in patients with multiple sclerosis is around 15%. Untreated depression is associated with suicidal ideation, impaired cognitive function and poor adherence to immunomodulatory treatment. For these reasons, systematic screening and management of depressive symptoms is recommended for all patients with multiple sclerosis. There is some evidence that interferon-β treatment may exacerbate depressive symptoms and a switch to glatiramer acetate can be envisaged in patients treated with an interferon-β in whom depressive symptoms become an issue. Fatigue is present in over three-quarters of patients with multiple sclerosis. It is considered the most debilitating symptom of the disease and is a major reason for work absenteeism. There is growing evidence that immunomodulatory treatments, in particular glatiramer acetate, improve fatigue symptoms in patients with multiple sclerosis.