The authors have as a goal to conduct a reflection about an important public health problem that is the influence of neuro-psychiatric disease in a patient sexual behaviour. Thus, a case study is described of a patient, of 49 years old, hospitalized with bipolar affective disorder diagnosis – depressive phase, in which unprotected sexual intercourse was predominant with several partners.

Clinical observation, conducted during three months of hospitalization, showed a sexual behavioural inadequacy, which was not justified by decompensation of the psychiatric feature previously referred. We also verified a cognitive dysfunction.

The results of this clinical evaluation, including neuropsychological evaluation and organic complementary study (ACT-CE and SPECT), suggest the diagnosis of front-temporal dementia.

The authors finish emphasising the existence of psychiatric disorders, functional and organic, with sexual risk behaviours. For several reasons, the psychiatric patients are more vulnerable to the STDs, namely because of clinical situations that for temporary or permanent ways determine the diminishing or absence of insight related to sexual behaviour.