The development, validity, and reliability of the Addiction Profile Index (API).

Objective: The objective of this study was to develop a practical questionnaire for multidimensional assessment of problems associated with alcohol and substance abuse that would also be useful for treatment planning.

Materials And Methods: The Addiction Profile Index (API) is a self-report questionnaire consisting of 37 items and the following 5 subscales: characteristics of substance use; dependency diagnosis; the effects of subsance use on the user; craving; motivation to quit using substances. The study included 345 alcohol and/or substance abusers from 2 addiction treatment clinics and a prison addiction service. The validity of the questionnaire was assessed using the Michigan Alcoholism Screening Test (MAST), Readiness to Change Questionnaire (SOCRATES), Penn Alcohol Craving Scale (PACS), Drug Craving Scale (DCS), Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I), and Addiction Severity Index (ASI).

Results: The Cronbach's alpha coefficient for the total API was 0.89 and for the subscales it ranged from 0.63 to 0.86. Item-total correlation coefficients ranged from 0.42 to 0.89. The Spearman Brown split-half method coefficient for the total API was 0.83. In all, 4 factors were obtained using explanatory factor analysis that represented 52.3% of the total variance. The API craving subscale was observed to be consistent with PACS and the API motivation subscale was consistent with SOCRATES. The API total score was strongly correlated with the mean MAST score, and the composite ASI medical status, substance use, legal status, and family social relations subscale scores. Based on ROC analyses, the area under curve was 0.90. With a total API cut-off score of 4, the scale's sensitivity and specificity 0.85 was 0.78, respectively.

Conclusion: The findings show that the API is a valid and reliable questionnaire that can be used to measure the severity of different dimensions of substance dependency.