Objective: The present study was performed to investigate the validity and reliability of the Korean version of the THINC-it tool (THINC-it-K) in adult patients with major depressive disorder (MDD).
Methods: Subjects aged 19-65 years with recurrent MDD experiencing moderate to severe major depressive episode (n=44) were evaluated and compared to age and sex matched healthy controls (n=44). Subjects completed the THINC-it-K which includes variants of the Identification task using Choice Reaction Time (IDN), One-Back Test (ONB), Digit Symbol Substitution Test (DSST), Trail Making Test-Part B (TMT-B), and the Perceived Deficits Questionnaire for Depression-5-item (PDQ-5-D).
Results: A total of 75.0% of patients with MDD exhibited cognitive performance 1 SD or below. The differences in Spotter (p=0.001), Codebreaker (p=0.001), PDQ-5-D (p<0.001) and objective THINC-it-K composite score (p=0.002) were significant between the two groups. Concurrent validity of the THINC-it-K based on a calculated composite score was good (r=0.856, p<0.001), and ranges for each component tests were from 0.076 (IDN) to 0.928 (PDQ-5-D).
Conclusion: The THINC-it-K exhibits good reliability and validity in adults with MDD. It could be a useful tool for the measurement of cognitive deficits in persons with MDD and should be implemented in clinical practice.