Overview and initial validation of two detailed, multidimensional, retrospective measures of substance use: the Lifetime Substance Use Recall (LSUR) and Longitudinal Substance Use Recall for 12 Weeks (LSUR-12) Instruments.

Research on comorbidities between substance use disorders and serious mental illnesses would be facilitated by new methods for collecting comprehensive data on substance use, including data on onset, progression, frequency, amounts, and consequential behaviors. Given substantial limitations of available instruments, and a nearly complete absence of methodologies that allow derivation of continuous measures that estimate dose or cumulative exposure, this report describes the development and initial validation of two interviewer-administered, multidimensional measures of substance use, the Lifetime Substance Use Recall (LSUR) and Longitudinal Substance Use Recall for 12 Weeks (LSUR-12) Instruments. Participants (n=60) in an ongoing study of first-episode psychosis were evaluated with the LSUR, LSUR-12, and a number of other concurrent measures pertaining to substance use, substance use disorder diagnoses, select demographic features, and two personality traits. Specific a priori hypothesis tests were selected to demonstrate validity, relying on effect sizes to estimate strengths of association, considering small-to-medium correlations (e.g., ρ) as |.20-.50| and medium-to-large effect sizes as >|.50|. Numerous associations were observed between key nicotine-, alcohol-, and cannabis-related variables from the LSUR and LSUR-12 and scores from other concurrently administered measures. These findings provide a thorough initial validation of scores obtained with the new multidimensional instruments. Although validity of the two new measures of lifetime and past 12-week substance use was demonstrated, empirical data on inter-rater and test-retest reliability are needed. Careful development, and demonstration of psychometric properties, of these and related instruments may advance the fields of addiction and comorbidity research.