[Depression and associated organic pathologies, a still under-estimated comorbidity. Results of the DIALOGUE study]

The field of comorbidity between organic pathologies and mood disorders remains insufficiently explored, whereas such comorbidities predict a more unfavorable outcome of both mood disorders and organic pathologies themselves.

The purpose of the Depression and organic diseases study (DIALOGUE) was to obtain in France a set of quantitative data on the prevalence of comorbidities between major depressive episodes (MDE) and associated chronic organic pathologies (ACOP), as well as on the diagnostic and therapeutic difficulties encountered in the management of such comorbidities in daily medical practice.

General practitioners (GP) and private or hospital psychiatrists were invited to collect several socio-demographic, clinical and therapeutic data on five consecutive patients corresponding to the inclusion criteria. Four groups of patients were set up: 2 082 patients followed up in primary care by their GP for a chronic somatic pathology (GPS group), as well as 2 017, 1 335 and 522 patients respectively followed up in primary care (PPD group), private (GPD group) or hospital psychiatry (HPD group) for a depression not already treated, or requiring modification of its pharmacological treatment (GPD, PPD and HPD group).

Among the patients of the GPS group, 41% presented with an associated MDE and, among the depressed patients of the three other groups, respectively 47, 55 and 63% presented with an ACOP. MDE were rather old (more than six months of duration) and severe. However, only 20% of the MDE in the GPS group had a treatment in progress, while in 74% of these same cases the onset of MDE was retrospectively dated more than 2 months before the day of the inclusion in the study. The ACOP, whose functional impact was judged as more severe (cancer, HIV, neurological diseases, renal insufficiency, osteo-articular diseases, insulino-dependent diabetes and coronary heart disease) were more often considered as responsible for the concomitant MDE and more often followed up in psychiatric settings than the other pathologies. Among the overlap signs between the ACOP and the MDE, fatigue was cited first and embarrassed psychiatrists more than GPs, contrary to sleep disorders. In spite of the diagnostic difficulties related to the comorbidity and recognized by all the physicians, GPs seldom asked for the opinion of a psychiatrist (5%) and appealed less often than psychiatrists to the cognitive and affective signs specific of the depression (low self-esteem, anhedonia).

The unrecognized frequency in the association between depression and organic pathologies pleads for closer cooperation between GPs and psychiatrists, as for continuous training not only of the GPs, but also the psychiatrists, in order to limit the observational biases and the therapeutic hesitations induced by these comorbidities.