The Marijuana Screening Inventory (MSI‐X): Reliability, Factor Structure, and Scoring Criteria with a Clinical Sample

Abstract

Objective: This study continues the psychometric evaluation of a 31‐item Marijuana Screening Inventory (MSI‐X) with adults referred to a substance abuse clinic, by determining MSI‐X reliability, factor structure, scoring cutoff accuracy, sensitivity, and specificity with a DSM‐IV‐TR criterion measure. Method: A “marijuana inventory” containing demographic, MSI‐X, and DSM IV‐TR diagnostic items was administered to 107 adults undergoing substance‐use evaluation. Results: The MSI‐X reliability was. 90 with factor analysis deriving nine factors explaining 72.2% of the variance. Varimax rotation supports retention of all 31 items on nine factor‐based scales. Receiver operating characteristic analysis determined MSI‐X accuracy and cutoff points in relation to four DSM IV‐TR diagnostic classifications. The MSI‐X obtained the highest probability (.91) for accuracy in identifying both cannabis dependence and abuse, with six the optimal cutoff for maximum sensitivity (.83) and specificity (.89). Thus, MSI‐X scores of ≥ 6 are considered high risk. A cutoff score of 3 was associated with (probability,. 90; sensitivity,. 85; specificity,. 81) identifying cannabis abuse only risk, providing a 3 to 5 score in the moderate risk range. Conclusions: Clinical sample data supports the psychometric usefulness of the MSI‐X as a screening tool. Marijuana lifetime use was 90% and past‐year use 48%. The MSI‐X identified 43% of lifetime users and 29% of past year users with moderate to high risk marijuana patterns deserving comprehensive evaluation. More males (15.9%) than females (7.5%) obtained MSI‐X high‐risk scores. The MSI‐X empirically derived cutoff scores are within one point of the theoretical clinical cutoffs previously reported.

• Marijuana
• Screening
• Cannabis abuse
• Marijuana screening inventory (MSI‐X)
• Drug abuse