and test-retest reliability has been reported 0.85. The concurrent validity with Zoweng Depression Scale has been
0.87 and with Hamilton Scale has been 0.95. This questionnaire has two factors: the first factor is depression and the
second one is mental-social activity. Questions 2, 9 and 13 are on the second factor and other questions are on the
first factor. GDS is a short form consisting of 15 questions derived from a 30-question form. Its alpha coefficient is
0.9 which similar studies have been performed in China, England and Malaysia and its variable has been between
0.7 and 0.9. Its test-retest variability has been 0.7 to 0.84, division method, 0.82; cut-off point, 3.4; sensitivity, 0.8-
0.9; and characteristic, 0.65-0.88 and with cut-off points 6.7 and 0.8. In the studies performed in Poland, the
sensitivity has been ranged between 0.52 to 0.67 variables (Malakouti and colleagues, 2006). By reviewing Maleki
validity, there has a significant difference between the GDS-15 scores of the two depressed and non-depressed
groups determined by CIDI. On the other hand, correlation coefficient among a number of positive criteria of basic
depression diagnosis and neurosis was calculated by GDS scale score. Correlation coefficient for 15-question form
was 0.35 (basic depression) and 0.4 (neuroticism) and for 11-question form 0.37 and 42.
3.