Psychometric studies of the Swedish version of the Adolescent Drug Abuse Diagnosis (ADAD) instrument

Sammanfattning: This thesis describes studies into the psychometric properties of a Swedish language version of the Adolescent Drug Abuse Diagnosis (ADAD) instrument. The psychometric properties of this instrument have been examined in two previous studies: an American study was conducted by the developers of the interview, Friedman and Utada (1989), and a Swiss study was undertaken by Bolognini et al. (2001). The American and the French (as used in the Swiss study) versions of ADAD exhibit good validity and reliability, in the form of both interrater reliability and the internal consistency of the composite scores. Study I evaluated the psychometric properties of the Swedish version of the ADAD interview in normal adolescents and adolescents with antisocial problems. It was found that the instrument has good interrater reliability, that the composite scores exhibit moderate internal consistency, and that the concept validity was acceptable and similar to that of the American and Swiss versions. The results also showed that the problem areas of ADAD produced meaningful correlations. The interviewer ratings, the adolescent’s ratings and the composite scores were compared and discussed. Some problems concerning the composite scores were discovered and will need to be analyzed in future studies. Study II investigated the utility and problems associated with the composite scores in the ADAD within and between normal adolescents and adolescents with antisocial problems. When comparing interviewer severity ratings and composite scores within the two groups, the composite scores were found to behave differently to the interviewer ratings. For normal adolescents, the composite scores are generally higher than the interviewer ratings, but for the adolescents with antisocial problems the reverse is true. The interviewer severity ratings seem to be the most appropriate outcome when the objective is to separate antisocial and normal groups of adolescents from each other. The difference between the two groups is smaller as measured by composite scores. The composite scores appear to function as viable indicators of current problems in all areas except for Medical and Alcohol problem area. The critical items within the Medical and Alcohol composite scores are explored and discussed.  Study III investigated the concurrent and predictive validity of the ADAD Psychological status and problem area. Concurrent validity was demonstrated by significant correlations between the ADAD, Youth Self Report (YSR) and Beck Depression Inventory (BDI) scores. The predictive validity of this problem area of the ADAD was tested by exploring its correlations with the YSR, BDI, and DICA problem ratings; moderate correlations were observed, suggesting that in clinical practice, the ADAD Psychological status and problem area may be a useful tool for the assessment and measurement of current psychological problems. The utility obtained by making decisions using the test is substantial. Overall, the results of these studies indicate that the Swedish version of ADAD appears to be a psychometrically good instrument for assessing the severity of adolescents’ problems and their need for treatment, but there are some problems with the Medical and Alcohol composite scores.