To the Editor: A 19-year-old woman with relapsing–remitting multiple sclerosis experienced subacute behavioral changes, with disinhibition, impulsiveness, and conversion drop attacks, which were related to acute lesions in the right orbitofrontal cortex. Although drop attacks remitted, her poor impulse-control persisted, suggesting an organic personality disorder. Neuropsychiatric symptoms in multiple sclerosis (MS) usually form part of a chronic psychiatric disorder, but they may also have a subacute temporal course.

The patient was a 19-year-old woman high school graduate with relapsing and remitting MS that started with symptoms at age 15. She did not have any previous history of psychiatric disease. In February of 2009 she began to show irritability and emotional fluctuations; she abandoned her university education, and started to live a libertine life that generated serious conflicts with her parents. She acted impulsively, without respect for social limits or circumstances, and had disinhibited and childish behavior. About 1 month later, her actions became increasingly bizarre, and she began to have frequent drop attacks without impairment of consciousness. These attacks were associated with intense anxious feelings that lasted a few minutes. She was hospitalized 1 month after the symptoms began. No focal signs were found in the neurological examination. Serum test and electroencephalography were normal. Brain MRI showed new hyperintense T2 lesions, one in the right orbitofrontal gyrus, with gadolinium enhancement, and a non-enhancing lesion in the left amygdala. She was treated with intravenous methylprednisolone 1 g/day for 3 days; aripiprazole 15 mg/day, and sertraline 50 mg/day for 1 month. The drop attacks remitted completely with the treatment, but her poor impulse-control and emotional instability persisted. Subsequently, she began to cut her forearms with sharp objects, without suicidal intention. A psychiatric evaluation done after the hospitalization concluded that she had an organic personality disorder.

Although many of the symptoms that were shown by our patient are compatible with the main features of a borderline personality disorder (impulsivity, emotional instability, dissociation, self-injuring behavior), their beginning was temporally related to new brain lesions, and had a subacute temporal course with partial remission after 2 months. Thus, these symptoms are very likely to be secondary to a relapse of multiple sclerosis. As the majority of cases reported of relapses with neuropsychiatric symptoms, the psychiatric morbidity persisted, making a great impact in the patient's social functioning.¹ Using the five-factor model of personality, it had been found that personality traits in MS are correlated with executive dysfunction² and euphoria.³ This gave rise to the theory of a frontal syndrome as the origin of personality disorders.² This is complementary with the results of another study finding that hypometabolism in the right orbito-frontal cortex and parahippocampal gyrus were related to the “psychotic variant of personality maladaptation in MS.”⁴ The orbito-frontal cortex is essential for regulating social interactions, and its lesions have been significantly related to behavioral abnormalities, euphoria, and impulsiveness, constituting an “orbito-frontal syndrome,” like our patient's behavior. Lesions in the frontal and left temporal cortex had been consistently found in other cases of MS with psychiatric relapses,^1,5 but, as far as we know, this is the first report of a psychiatric relapse related to a gadolinium-enhancing lesion in the orbito-frontal cortex.