AbstractKessler k6 psychological distress scores are analyzed using a count model and item response theory (IRT) models are applied to the items which produce the k6 score and generate an alternative distress score, θ*. Other ways of utilizing the constituent items are also examined. The data used in the analysis comes from the 2014 National Survey of Drug Use and Health. Three important results emerge. First, θ* and k6 are not highly correlated and their distributions are quite different. The k6 score gives a much more favourable picture of mental health than θ*. Second, k6 does a much better job in explaining participation in treatment programs than θ* suggesting a very limited role for IRT methods in the analysis of psychological distress data. As a diagnostic tool k6 is an effective and simple way of summarizing the item data. Third, for researchers interested in which individual characteristics determine psychological distress better results are obtained by analyzing the six constituent items which are used to generate the k6 score using ordered probability models rather than k6 itself.