Abstract
In recent years, major depressive disorder (MDD) has began to become a very heavy burden for the public health system due to its various aspects like chronicity, resistant and debilitating symptomatology and apart from that, the eventual health care expenses. Reported comorbid psychiatric diseases are also suspected to be responsible for this burden. The objective of this study is to contribute the epidemiological data pool of MDD and subsequent researches to identify etiological factors of MDD and provide basis for resource managment studies for MDD. In this paper, we present the results of our study concerning the psychiatric comorbidity and sociodemographic aspects of MDD patients in Mersin region of Turkey, a seaside town on Mediterranean peninsula. The archives of our psychiatry department were searched thoroughly for the records of outpatients with established MDD diagnoses for the data about age, sex, marital status, education level, occupation, their HAM-A (Hamilton Anxiety Scale) and HAM-D (Hamilton Depression Rating Scale) scores and comorbidity. A total of 311 patient records 64 male (20%), 247 female (80%) were included in the study. Our results revealed that 80.7% of the subjects (251) were diagnosed as being affected from pure major depressive disorder, while the remaining 19.3% (60) were presented a comorbid psychiatric disorder along with the MDD. Results of this study point out that a decline in MDD diagnoses accompanies the decrease of education levels and MDD’s most frequent comorbid psychiatric disorder is panic disorder. Comorbidity in depressive disorder affects the duration of depressive episode, functionality in general, and response to treatment. Hence, it is very important to notify major depressive disorder and its comorbid disorders.

Key words: Major depressive disorder, comorbidity, epidemiology, sociodemographic data