Stability, reliability, and validity of the THINC-it screening tool for cognitive impairment in depression: A psychometric exploration in healthy volunteers.

OBJECTIVES: There is a need for a brief, reliable, valid, and sensitive assessment tool for screening cognitive deficits in patients with Major Depressive Disorders. This paper examines the psychometric characteristics of THINC-it, a cognitive assessment tool composed of four objective measures of cognition and a self-rated assessment, in subjects without mental disorders.

METHODS: N = 100 healthy controls with no current or past history of depression were tested on four sequential assessments to examine temporal stability, reliability, and convergent validity of the THINC-it tests. We examined temporal reliability across 1 week and stability via three consecutive assessments. Consistency of assessment by the study rater (intrarater reliability) was calculated using the data from the second and third of these consecutive assessments.

RESULTS: Test-retest reliability correlations varied between Pearson's r = 0.75 and 0.8. Intrarater reliability between 0.7 and 0.93. Stability for the primary measure for each test yielded within-subject standard deviation values between 5.9 and 11.23 for accuracy measures and 0.735 and 17.3 seconds for latency measures. Convergent validity for three tasks was in the acceptable range, but low for the Symbol Check task.

CONCLUSIONS: Analysis shows high levels of reliability and stability. Levels of convergent validity were modest but acceptable in the case of all but one test.