Psychometric Properties of the Persian Version of Chicago Multi-Scale Depression Inventory

Article excerpt

Objective: The aim of this study was to evaluate the psychometric properties of the Persian version of Chicago Multi-Scale Depression Inventory (CMDI) in Iranian subjects.

Method: CMDI was translated into Persian according to the standard method. Two hundred and sixty two medical students (of whom, 114 were re-tested 5-10 days after the first test), Archibald 40 patients with major depressive episodes, 23 patients with multiple sclerosis, 21 patients with epilepsy, and 43 normal persons selected from acquaintances of the patients were included in the study. Samples were matched for age, sex, marital status, and education. Exclusion criteria were as follows: neurologic diseases (except multiple sclerosis or epilepsy) or head trauma, serious medical condition, alcohol or opioid abuse. Subjects were omitted if they did not answer any of the items in BDI-II or CMDI. Demographic questionnaire, BDI-II, and CMDI were given to the subjects.

Results: The mean scores of CMDI and its subscales for depressed people were significantly different from multiple sclerosis patients, normal people, and medical students. The mean score of mood subscale for epilepsy patients was significantly different from normal people. The mean score of CMDI and evaluative and vegetative subscales for epilepsy patients were significantly different from the normal subjects and medical students. Correlation coefficient between BDI-II and CMDI was 0.86. Reliability and internal consistency coefficients for CMDI were 0.92 and 0.95 respectively. Cut off scores for CMDI and mood, evaluative, and vegetative subscales were 123, 46, 36, and 44 respectively.

Conclusion: The Persian version of CMDI has content, convergent, and discriminant validity and is reliable and internally consistent. These findings support the use of CMDI in Persian participants.

Keywords: Depression, Iran, Psychological tests, Psychometrics

Iran J Psychiatry 2009; 4:137-142

Depressive disorders are co-morbid with many chronic medical diseases including neurologic, cardiovascular, pulmonary, endocrinologic, and neoplastic diseases (1- 2). To some extent, the symptoms of those co-morbid diseases are similar to major depressive symptoms. Similarity falls between vegetative or somatic symptoms such as fatigue, sleep, or sexual disturbance. In patients with such symptoms, clinical diagnosis of depression might be a matter of debate. As most of the depression scaling systems are developed and standardized for psychiatric patients (3), using them in other medical settings may lead to overdiagnosis of depressive disorders and their severity (4). To measure those depressive symptoms related to chronic medical diseases, and to discriminate them from those in depressive disorders, Nyenhuis et al (3, 5) developed the Chicago Multi-scale Depression Inventory (CMDI), which is a self-report depression questionnaire. In their preliminary study, 30.5% of the multiple sclerosis patients were depressed while they were tested by BDI. This figure was 17.7% when they were tested with CMDI (5). More studies showed acceptable results and good factorial model of CMDI (6). This scale has previously been translated in to Italian by Solari et al (7). They evaluated CMDI psychometric properties in Italian culture. Forn et al, and Julian et al, used CMDI as a tool for screening depression in multiple sclerosis patients to determine the nature of cognitive disturbance and the role of anxiety and depression in executive functioning of the patients (8, 9).

In this report, the Persian version of CMDI was developed and evaluated in normal subjects, patients with depression, and patients with two chronic neurological diseases of multiple sclerosis and epilepsy.

Materials and Methods

Participants

Two group of normal volunteers and four groups of patients participated in the present study. The normal group included 313 medical students of Tehran University of Medical Sciences. …