Affective disorders are complications of many nervous system diseases. Pathological laughing and crying may accompany cerebrovascular lesions, multiple sclerosis, ALS, Alzheimer disease or cerebral tumours. Precise mechanisms of how these disorders arise are still unknown. Reviews of the literature were been accomplished in the article where, taking the examples of stroke and multiple sclerosis, have been discussed: the clinic picture, pathogenesis in neuroanatomic and neurophysiologic aspects as well as diagnostic criteria and the treatment of uncontrolled pathological laughing and/or crying.