Psychiatric disorders have a remarquable frequency in multiple sclerosis. The leading group of these disorders consists of affective disorders. These psychiatric conditions can worsen the outcome of multiple sclerosis, thus contributing to increase the burden of the disease to both patients and relatives. Managing such a complicated situation needs a focus on the underlying links between affective disorders and multiple sclerosis.

To examine the hypotheses proposed to explain the high prevalence of affective disorders in patients with multiple sclerosis.

Literature was reviewed using the Medline database and the following keywords “bipolar disorder” “affective disorder”, “mania” and “multiple sclerosis”.

PubMed research returned 13 results. After manual inspection, 10 articles were retained and examined. The cause of the high comorbidity between multiple sclerosis and mood disorders is regarded as being multifactorial: the medication used in multiple sclerosis possibly inducing/exacerbating mood disturbances, the demyelinazing brain lesions which could bring about depression or mania, genetic overlapping with affective disorders and last the psychological reactions and adjustment difficulties to the neurological handicap.

Despite the fact that the higher prevalence of affective disorders in multiple sclerosis is well established, these disorders still remain underdiagnosed and undertreated. A shift towards a better assessment of the psychiatric comorbidity in multiple sclerosis patients and the optimal treatment of those disorders is fundamental.

The authors have not supplied their declaration of competing interest.