**9. Euphoria in multiple sclerosis**

The definition of euphoria includes the description of a constant extreme happiness and happiness, an inadequate animation, or a absence of interest in the concerns of repercussion of the disease. This disorder arises as a sequence of personality related disorders and it is not defined as a disposition related disorder. Euphoria represents a distinct disorder compared with mania. This disorder is correlated with the apparition of the following features: infantilism, spontaneousness, emotional impairments, anger attacks, and absence of sympathy. In recent studies from literature, the occurrence of euphoria was reported to be approximately 15% in patients with multiple sclerosis.

In a study by Diaz-Olavarietta et al. [65], which included 44 patients as MS group and 25 healthy patients as control group, the prevalence of euphoria was reported to be present in 13% of the patients presenting multiple sclerosis, meanwhile the control group was euphoria-free.

In a study conducted by Fishman et al. [66], which included 75 patients with multiple sclerosis, was reported a presence of euphoria in 7% of the multiple

sclerosis patients, compared with the healthy subjects which did not present any of the symptoms associated with euphoria.

Euphoria is neuroimagistically correlated with the rigor of the amount T2 lesions and the degeneration of gray and white matter [67].
