Psychometric qualities of the Thought Suppression Inventory-Revised in different age groups

Intrusive thoughts about negative events are core symptoms of several psychiatric disorders. Because current instruments for the assessment of thought suppression are unsatisfactory, we developed and evaluated the dimensionality and validity of a questionnaire that distinguishes between three major facets of thought suppression - intrusions, suppression attempts, and effective suppression - that affect psychopathology distinctly. Participants (N = 784) divided over three age groups, 25 years and younger (n = 351), between 26 and 50 years (n = 202), and 51 years or older (n = 231), completed the Thought Suppression Inventory-Revised. The data were analyzed with sophisticated nonparametric item response theory. Exploratory Mokken scale analysis revealed a three-factor structure, which was affirmed with confirmatory analyses. The Suppression Attempts scale appeared to be a weak scale, specifically in the two older age groups. Since suppression most likely depends on inhibitory ability - which declines with age - suppression attempts probably have increasingly variable outcomes (i.e., failure or success), which complicates measuring this factor. Overall, our findings suggest that three facets of thought suppression can be measured especially in younger individuals, but that for individual measurements particularly in the older age groups the Suppression Attempts scale has to be used with caution.