The Delusional disorder is uncommon, accounting for 2–8% of all hospital admissions for non-organic psychotic disorder and is usually initiated after the third decade of life. It is characterized primarily by one or more non-bizarre delusions, and according to the content of delusions, can be divided into five subtypes: persecution, jealousy, erotomanic, somatic and grandeur.

We present a case of a patient with Jealousy Delusional Disorder and discuss the main difficulties that arise in the differential diagnosis and treatment.

In the differential diagnosis is essential to eliminate the pathologies of organic causes that may have delusions as clinical manifestation. It is then necessary to distinguish delusion from obsessive ideas and overvalued ideas that can lead to misdiagnosis and therefore have serious implications in monitoring and treating of these patients.

The subtype of jealousy seems to have a better evolution and prognosis compared with others subtypes reported.

Although the Delusional Disorder present a more favorable course and usually is associated with a smaller disturbance in the overall functioning of the patients, they have a poor compliance to psychiatric treatment. So, they often stop psychiatry follow-up and discontinue therapy.