Assessment of rates of recanting and hair testing as a biological measure of drug use in a general population sample of young people

AIMS

We investigate the extent of and factors associated with denial of previously reported cannabis and other illicit drug use, and assess the potential of hair testing for measuring substance use in general population samples.

DESIGN

Birth cohort study.

SETTING

United Kingdom, 1991-present.

PARTICIPANTS

A total of 3643 participants who provided hair and self-report measures of cannabis and other illicit drug use in the Avon Longitudinal Study of Parents and Children (ALSPAC) at age 18 years.

MEASUREMENTS

Denial of ever use of cannabis and other illicit drugs at age 18 following previously reported use. Positive hair drug tests for cannabis and other illicit drugs, and expected numbers of false positives and false negatives based on expected sensitivity and specificity.

FINDINGS

Cannabis and other illicit drug use was reported by 1223 and 393 individuals, respectively, before age 18 years. Of these 176 (14.4%) and 99 (25.2%), respectively, denied use at age 18. Denial of cannabis use decreased with the reporting of other substances and antisocial behaviour. Cannabis and other illicit drug use at age 18 was reported by 547 (22.5%) and 203 (8.4%) individuals, respectively. Of these, 111 (20.3%) and 13 (6.4%) were hair-positive for cannabis and other illicit drugs, respectively. Based on hair testing for cannabis use we expect 0 [95% confidence interval (CI) = 0-169] false positives and 394 (95% CI = 323-449) false negatives compared to observed 362 potential false positives and 436 potential false negatives based on self-report. In hair-positive individuals, reporting the use of other substances and antisocial behaviour decreased the odds of a negative self-report.

CONCLUSIONS

Hair analysis provides an unreliable marker of substance use in general population samples. People who report more frequent substance use before age 18 are less likely to later deny previous substance use at age 18 than people who report occasional use.

Testing the length of time theory of recall decay: examining substance use report stability with 10 years of national longitudinal survey of youth data

AIM

This article examines whether the proportion of recanters increases (or decreases) as a function of time o test length of time theory.

SAMPLE

2,221 US respondents in the National Longitudinal Survey of Youth child data. Bivariate and logistic regression analyses were used.

RESULTS

Among recanters, 50% of cigarette and alcohol users recanted use by 4 years, and 50% of marijuana users recanted by 3 years. Predictors of recanting was being Black or Hispanic and younger age. The theory was not supported. Further research is needed to identify potential reasons why adolescents recant their use is such a short time span. The study's limitations are noted.

Recanting of life-time inhalant use: how big a problem and what to make of it

AIMS

To establish the prevalence of recanting of life-time inhalant use, identify correlates of recanting to gain insight to its causes and develop a method for distinguishing recanters who truly are versus are not life-time users of inhalants.

DESIGN AND SETTING

Longitudinal survey data from students in 62 South Dakota middle schools who were participating in a field trial to evaluate a school-based drug prevention program.

MEASUREMENTS

At grades 7-8, participants reported on their life-time inhalant use, other drug use and drug-related beliefs, attitudes and behaviors.

FINDINGS

Forty-nine per cent of students who reported life-time inhalant use at grade 7 recanted their reports a year later. Comparison of students who recanted inhalant use with those who did or did not report inhalant use consistently on drug-related beliefs, attitudes and behaviors at grades 7 and 8 suggested that, whereas some inhalant use recanting reflects denial of past behavior, some reflects erroneous initial reporting. Based on a latent mixture model fitted to the multivariate distribution of grade 7 and grade 8 responses of recanters and consistent reporters, we calculated the probability that each recanter was, in fact, a life-time inhalant user. An estimated 67% of the recanters in our sample appear to be life-time inhalant users who admitted use in grade 7 and then denied that use at grade 8; 33% appear to be students who reported use incorrectly at grade 7 and then corrected that error at grade 8.

CONCLUSIONS

Inhalant use recanting is a significant problem that, if not handled carefully, is likely to have a considerable impact on our understanding of the etiology of inhalant use and efforts to prevent it.

What are the consequences of relying upon self-reports of sexually transmitted diseases? Lessons learned about recanting in a longitudinal study

PURPOSE

Self-reports are the standard measure of STD history used in survey research. We explored to what extent self-reports of ever having an STD are recanted in a follow-up data collection.

METHODS

Using the National Survey of Adolescent Males (NSAM), we assessed consistency over time in self-reports of ever having an STD in a sample of young men transitioning from adolescence to young adulthood (aged 15-26 years), a population in which STDs are particularly prevalent.

RESULTS

Approximately 7% of all sexually experienced young men rescinded STD self-reports over time. Thus, self-reports at one point in time likely underestimate true STD history, using earlier self-reports as the criterion. Among men who ever report an STD, 94-98% recant their reports in later waves.

CONCLUSIONS

Knowledge of the extent of underreporting can potentially be used to adjust cross-sectional estimates of STDs based on survey self-reports. These study findings move us one step closer to estimating just how much underreporting of STDs in self-reports is.

Consistency of self-reported smoking over a 6-year interval from adolescence to young adulthood

AIMS

To examine the reliability of self-report cigarette smoking questions by describing recanting (denial of previous smoking reports) in a nationally representative sample of US adolescents followed throughout young adulthood. Predictors of recanting across stages of smoking uptake/progression are examined.

DESIGN

A total of 12 985 respondents to cigarette smoking questions during in-home interviews at waves I and III (6 years apart) of the National Longitudinal Study of Adolescent Health (Add Health). The sample survey procedures of Stata 9.0 were used to produce nationally representative estimates, with standard errors adjusted for both clustering at the school level and stratification by geographical region.

MEASUREMENTS

Recanting probabilities determined by reports of stages of smoking uptake/progression at each time-point were predicted by race/ethnicity, parental education, household income, poverty level, depression and peer daily smoking.

FINDINGS

Stage-specific results indicated that recanting is higher when the earlier smoking was less frequent/intense. Recanters were older, from lower-income households and had higher baseline depression levels. Non-Hispanic black youth were significantly more likely to recant previous smoking compared to non-Hispanic white youth, even in multivariate models controlling for socio-demographic variables. Predictors of recanting differed by level of tobacco involvement. The greater likelihood of non-Hispanic black respondents to deny previous smoking may be a reflection of less intense or more intermittent use of tobacco that leads to recall differences over time.

CONCLUSIONS

Racial/ethnic subgroups and/or respondents endorsing depressive symptoms may be more vulnerable to misclassification during interpretation of national survey data and subsequently not identified properly for prevention/intervention programs.