Depressive symptoms are very common among referrals to general hospital and comprise the most frequent cause for psychiatric consultation. Comorbidity of medical and psychiatric disorders are common among uneducated, unemployed people with low income. These conditions make it difficult to recognize and treat such patient group. The prevalence of medical disorders increase when there is a difficulty in reaching health services. The depressive mood may decrease the persons willingness to access health service. Additionally, the problems in most of the people seeking for medical help are not recognized by the health providers. It is quiet difficult to diagnose depression in patients with medical disorders. Being sick, being in an hospital, inability to work, loss of functionality lead to a change in social roles which may cause mourning-like symptoms, symptoms quite similar to depressions. Besides, vegetative and somatic symptoms used for the diagnosis of depression can be direct consequences of the medical disorder itself. Thus such phenomenological signs and symptoms are suggested not to be considered as sufficient criteria for a diagnosis of depression among patients with medical disorder. This diagnostic complexity is also reflected in the studies searching for depression prevalence in medical disorders. For instance, the prevalence of depression ranges from 0% to 100% among renal patients. The physical signs and symptoms of medical conditions can overlap with the symptoms of depression and this overlap stands as one of the major diagnostic challenge for researchers. There are several other reasons that might explain the discrepancies in depression prevalence among patients with medical disorders such as changes in diagnostic criteria over time, use of different diagnostic scales for depression, and studying the prevalence of depression in non-standardized populations. Depression prevalence is affected from demographic variables, type, severity and chronicity of comorbid medical disorder. The differences in the prevalence rates brings questions about reliability and validity of diagnostic tools used. Though using DSM and ICD as diagnostic tools have standardized the psychiatric diagnosis in many ways, there still remains some difficulties for reaching valid psychiatric diagnosis among patients with medical disorders. Controversies and discussions about reliability and validity problem in this issue still continues. Subclinical depressive symptoms in medical disorders, effect of comorbidity on the diagnostic process and lower interobserver agreement rates for the diagnosis of depression due to a general medical condition are among several factors that should be carefully investigated to overcome these problems.
Depression, Medical disorder, Comorbidity, Classification