The review concluded that there was fair evidence that standardised questionnaires, considered short enough to be potentially useful in the practice setting, had acceptable accuracy and reliability in screening for drug use/misuse. Given the uncertain quality of the included studies and limited data presented, and the potential for bias in the review, the authors’ conclusions should be interpreted with caution.

To assess the accuracy and reliability of standardised screening instruments for the detection of drug misuse.

The Substance Abuse Screening and Assessment Instruments database of questionnaires and interviews was searched. MEDLINE and PsycINFO were searched between 1980 and August 2006 to identify relevant English language publications. Search terms were the title or acronym of relevant questionnaires.

Studies of validated screening instruments for the detection of drug misuse among asymptomatic patients seen in ambulatory general medical setting were eligible for inclusion if they were potentially useful for screening for drug misuse in primary care practice settings. Eligible questionnaires had to be designed to detect use/abuse of illicit drugs, contain no more than 20 items, and/or take no more than five minutes to complete or score.

Included studies were conducted in various settings in adults and adolescents. Participants had the following characteristics: in drug treatment; known drug problem; primary care patients; attending psychiatric or medical clinics; workers; academia; and school attendees. The following screening instruments were administered by a clinician and/or the patient: Alcohol, Smoking and Substance Involvement Screening Test (ASSIST - eight items); Cut down, Annoyed, Guilty, Eye-opener - Adapted to Include Drugs (CAGE-AID - four items); Car, Relax, Alone, Forget, Friends, Trouble (CRAFFT - six items); Drug Abuse Screening Test (DAST - 20 items); Relax, Alone, Forget, Friends, Trouble (RAFFT - five items); and Simple Screening Instrument for Substance Abuse (SSI-SA - 16 items). Most instruments assessed lifetime use of drugs rather than recent use.

Reference standards included diagnostic, clinical, structured or neuropsychiatric interviews, or a personal experience inventory (where reported). Other outcomes of interest were the feasibility or usefulness of any of the questionnaires when applied in the primary care clinical setting, and the clinical utility of the questionnaires in screening pregnant women for drug use or misuse.

The authors did not state how many reviewers selected studies for inclusion.

Study quality was assessed according to the US Preventative Services Task Force grading scales. Studies were rated as good, fair, or poor quality; good quality studies used a credible reference standard which was interpreted independently of the questionnaire, and included more than 100 patients with and without a drug use problem, some of whom were from a general clinic population.

The authors did not state how many reviewers performed the validity assessment.

Sensitivity, specificity, and positive and negative predictive values were extracted from individual studies.

The authors did not state how many reviewers extracted the data.

Data were presented as a narrative synthesis and in a table.

Sixteen studies were included in the review (n=3,775 participants; range 50 to 976). Studies were reported to be of good or fair quality.

The ASSIST (Alcohol, Smoking and Substance Involvement Screening Test) questionnaire (two studies) provided fair evidence of accuracy (sensitivity 90%; specificity 78%; one study) and good evidence of reliability.

The CAGE-AID (Cut down, Annoyed, Guilty, Eye-opener - Adapted to Include Drugs) questionnaire (three studies) provided good evidence of accuracy (sensitivity 79% to 92%; specificity 48% to 77%; two studies) and fair evidence of reliability.

The CRAFFT (Car, Relax, Alone, Forget, Friends, Trouble) questionnaire (four studies) provided good evidence of accuracy (sensitivity 76% to 92%; specificity 76% to 94%; three studies) and reliability.

The DAST (Drug Abuse Screening Test) questionnaire (four studies) provided fair evidence for accuracy (sensitivity 82% to 96%; specificity 71% to 91%; two studies) and reliability.

The RAFFT (Relax, Alone, Forget, Friends, Trouble) questionnaire (two studies) reported sensitivities of 84% and 89%, and specificities of 67% and 69%.

The SSI-SA (Simple Screening Instrument for Substance Abuse) questionnaire (one study) did not report sensitivity and specificity.

Negative predictive values were consistently greater than 90% for CAGE-AID, CRAFFT, and DAST, but not for RAFFT. Positive predictive values varied considerably between studies (12% to 91%).

There was fair evidence that standardised questionnaires, considered short enough to be potentially useful in the practice setting, had acceptable accuracy and reliability in screening for drug use/misuse. The evidence did not permit conclusions to be made about the overall clinical utility of these instruments when applied in a busy primary care practice setting or for screening pregnant women.

The review question was clear, but the supporting inclusion criteria were broad. The literature search was limited to two databases and, as the search was limited to English language publications, potentially relevant studies may have been missed. The authors did not state how many reviewers undertook each stage of the process, which meant that reviewer error and bias could not be ruled out.

A limited quality assessment was performed, but individual study ratings were not provided. Study details and population characteristics were lacking, so it was not possible to assess whether there was clinical and/or methodological heterogeneity. Given the potential for variability among the studies, a narrative synthesis seemed appropriate. However, the findings were somewhat limited, and only a small number of studies were included for each screening instrument.

Given the above limitations, the authors’ conclusions should be interpreted with caution.

Practice: The authors stated that it remains unclear how well some of the questionnaires perform in large populations of patients in general medical clinics or practices, where the prevalence of drug misuse problems is generally lower.

Research: The authors stated that further research is needed to determine the optimal trade-off between the length of a questionnaire and its accuracy/reliability. Further research is also needed to assess the acceptability of the additional burden placed on patients, clinicians, and staff when screening instruments are routinely used in practice.

Agency for Healthcare Research and Quality.

Polen MR, Whitlock EP, Wisdom JP, Nygren P, Bougatsos C. Screening in primary care settings for illicit drug use: staged systematic review for the United States Preventive Services Task Force. Rockville, MD, USA: Agency for Healthcare Research and Quality. Evidence Synthesis; 58, Part 1. 2008

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.