Comorbidity between two or more mental disorders is highly frequent. Depression is one of the diseases that more often accompanies other conditions.

The objective of this study is to establish the prevalence of depression in patients with delusional disorder and describe the treatment used in these cases.

The aim is to provide useful information regarding this frequent, often disregarded, comorbidity.

Our results proceed from the Andalusian delusional disorder case register. We reviewed 1927 clinical histories of patients diagnosed of delusional disorder. Upon having verified the diagnosis, following DSM-V criteria, we recollected several data, including sociodemographic factors, depression comorbidity and antidepressive treatment.

One thousand four hundred and fifty-two patients matched DSM-V delusional disorder criteria. 49,8% of our sample were women. Average following period was 9 years and 1 month, with an average of 0,84 hospitalizations. The prevalence of depression in patients with delusional disorders was 31,9%. 67,5% of them received some kind of antidepressive treatment. The antidepressive drugs most frequently used were selective serotonin reuptake inhibitors.

Depression is a highly prevalent condition among patients with delusional disorder. Most of them are on antidepressive treatment, the most employed of which is based on selective serotonin reuptake inhibitors. Comorbid depression can have an important impact on the course of delusional disorder. A correct diagnosis and treatment should be made to help improve the prognosis and life quality of these patients.

The authors have not supplied their declaration of competing interest.