Depression is the predominant psychological disturbance in Multiple Sclerosis (MS) with lifetime prevalence around 50% and annual prevalence of 20%. Depression is commoner during relapses and may exacerbate fatigue and cognitive dysfunction. The aetiology of depression is multifactorial and likely associated with psychological stress, focal demyelinating lesions and immune dysfunction. There is no correlation between age, gender, duration of illness and sex. Unlike it was believed for the treatment with interferon β, recent side effects data from clinical trials have failed to confirm that this medication is associated with an increased risk of depression in patients with MS. Treating depression improves quality of life and improves adherence to disease-modifying drugs. Treatment with pharmacotherapy is particularly challenging given the somatic symptoms overlap between MS and depression and the increased burden of their side effects.

To demonstrate the relationship between depression and MS.

We report a case of depression in a 32 year old woman with MS, treated twice with bolus of metilprednisolone, taking interferon β at present. Her psychopathological symptoms have been sadness, terminal insomnia, anorexia, fatigue, social isolation, anhedonia, increased worry, pessimism, loss of self-esteem and suicidal ideation (not structured). The pharmacotherapy used to treat the depression was firstly fluoxetine and lately venlafaxine.

There has been an improvement on the patient's symptoms related both to the depression and to the MS.

This case demonstrates once more, the complex relationship between those two clinical entities.