[ABSTRACT] A thorough review was carried out about presenil dementia and the current concepts according to the international classification of the mental dysfunctions and of the behavior (CIE-10) and the Statistics and Diagnosis Manual of the mental disorders DSM-IV. Afterwards, we present the case of a patient of the third decade of life who began with an anxious depressive clinical picture, he/she received treatment with antidepressant, appearing the neurological manifestations of the illness