A. C. Moss and I. P. Albery (2009) presented a dual-process model of the alcohol-behavior link, integrating alcohol expectancy and alcohol myopia theory. Their integrative theory rests on a number of assumptions including, first, that alcohol expectancies are associations that can be activated automatically by an alcohol-relevant context, and second, that alcohol selectively reduces propositional reasoning. As a result, behavior comes under the control of associative processes after alcohol consumption. We agree with the second but not with the first assumption, based on theoretical and empirical arguments. Although in some cases expectancies may involve a simple association, they are propositional in nature. We demonstrate that this assertion is supported by existing literature cited in Moss and Albery. Moreover, six recent studies consistently demonstrated that under circumstances where executive control is impaired (either as a stable individual difference or under the acute influence of alcohol), associative processes, over and above expectancies, predict alcohol-related behavior. Taken together, the evidence strongly suggests a fundamental distinction between expectancies and associations in memory: effects of propositional expectancies and executive functions are impaired under the acute influence of alcohol but memory associations are not. This difference in perspective not only has theoretical implications, but also leads to different predictions regarding acute alcohol effects in society.
Dual-Process Theories; Automatic and Controlled Processes; Acute Alcohol Effects
The automatic tendency to attend to, positively evaluate and approach alcohol related stimuli has been found to play a causal role in problematic alcohol use and can be retrained by computerised Cognitive Bias Modification (CBM). In spite of CBMs potential as an internet intervention, little is known about the efficacy of web-based CBM. The study described in this protocol will test the effectiveness of web-based CBM in a double blind randomised controlled trial with a 2 (attention bias retraining: real versus placebo) x 2 (alcohol/no-go training: real versus placebo) x 2 (approach bias retraining: real versus placebo) factorial design.
The effectiveness of 12 sessions of CBM will be examined among problem drinkers aged 18–65 who are randomly assigned to one of the eight CBM conditions, after completing two modules of a validated cognitive behavioural intervention, DrinkingLess. The primary outcome measure is the change in alcohol use. It is expected that, for each of the CBM interventions, participants in the real CBM conditions will show a greater decrease in alcohol use than participants in the placebo conditions. Secondary outcome measures include the percentage of participants drinking within the limits for sensible drinking. Possible mediating (change in automatic biases) and moderating (working memory, inhibition) factors will be examined, as will the comparative cost-effectiveness of the various CBM strategies.
This study will be the first to test the relative efficacy of various web-based CBM strategies in problem drinkers. If proven effective, CBM could be implemented as a low-cost, low-threshold adjuvant to CBT-based online interventions for problem drinkers.
Netherlands Trial register: NTR3875.
Problem drinking; Alcohol; Cognitive bias modification; Implicit cognition; E-health intervention
Cognitive biases, including implicit memory associations are thought to play an important role in the development of addictive behaviors. The aim of the present study was to investigate implicit affective memory associations in heavy cannabis users. Implicit positive-arousal, sedation, and negative associations toward cannabis were measured with three Single Category Implicit Association Tests (SC-IAT’s) and compared between 59 heavy cannabis users and 89 controls. Moreover, we investigated the relationship between these implicit affective associations and explicit expectancies, subjective craving, cannabis use, and cannabis related problems. Results show that heavy cannabis users had stronger implicit positive-arousal associations but weaker implicit negative associations toward cannabis compared to controls. Moreover, heavy cannabis users had stronger sedation but weaker negative explicit expectancies toward cannabis compared to controls. Within heavy cannabis users, more cannabis use was associated with stronger implicit negative associations whereas more cannabis use related problems was associated with stronger explicit negative expectancies, decreasing the overall difference on negative associations between cannabis users and controls. No other associations were observed between implicit associations, explicit expectancies, measures of cannabis use, cannabis use related problems, or subjective craving. These findings indicate that, in contrast to other substances of abuse like alcohol and tobacco, the relationship between implicit associations and cannabis use appears to be weak in heavy cannabis users.
cannabis; implicit association test; cannabis use disorder; craving; affective associations
Implicit and explicit self-esteem are assumed to be important factors in understanding the onset and maintenance of psychological problems. The current study aims to examine the association between implicit and explicit self-esteem and their interaction with depressive symptoms, suicidal ideation, and loneliness. Specifically, the relationship between the size and the direction of the discrepancy between implicit and explicit self-esteem with depressive symptoms, suicidal ideation, and loneliness were examined. Participants were 95 young female adults (M = 21.2 years, SD = 1.88) enrolled in higher education. We administered the IAT to assess implicit self-esteem, and the Rosenberg self-esteem scale to measure explicit self-esteem while psychological problems were assessed through self-reports. Results showed that discrepancies between implicit and explicit self-esteem were positively associated with depressive symptoms, suicidal ideation, and loneliness. In addition, the direction of the discrepancy was specifically relevant: damaged self-esteem (i.e., high implicit self-esteem and low explicit self-esteem) was consistently associated with increased levels of depressive symptoms, suicidal ideation, and loneliness. In contrast, defensive or fragile self-esteem (i.e., low implicit and high explicit self-esteem) was solely associated with loneliness. These findings provide further support that specifically damaged self-esteem is an important vulnerability marker for depressive symptoms, suicidal ideation, and loneliness.
damaged; implicit cognition; self-esteem; suicidal ideation; depression; loneliness
Research on implicit cognition and addiction has expanded greatly during the past decade. This research area provides new ways to understand why people engage in behaviors that they know are harmful or counterproductive in the long run. Implicit cognition takes a different view from traditional cognitive approaches to addiction by assuming that behavior is often not a result of a reflective decision that takes into account the pros and cons known by the individual. Instead of a cognitive algebra integrating many cognitions relevant to choice, implicit cognition assumes that the influential cognitions are the ones that are spontaneously activated during critical decision points. This selective review highlights many of the consistent findings supporting predictive effects of implicit cognition on substance use and abuse in adolescents and adults; reveals a recent integration with dual-process models; outlines the rapid evolution of different measurement tools; and introduces new routes for intervention.
implicit association; treatment; prevention; adolescents; college students; health behavior
Dual process models of addiction suggest that the influence of alcohol-related cognition might be dependent on the level of executive functioning. This study investigated if the interaction between implicit and explicit alcohol-related cognitions and working memory capacity predicted alcohol use after one month in at-risk youth. Implicit and explicit alcohol-related cognitions were assessed in 88 Dutch at-risk adolescents ranging in age from 14 to 20 (51 males) with an adapted version of the Implicit Association Test (IAT) and an expectancy questionnaire. Working memory capacity was assessed using the computer-based version of the Self-Ordered Pointing Task (SOPT). Alcohol use and alcohol-related problems were measured at baseline and after one month with self-report questionnaires. The hierarchical regression analysis showed that both the interaction between implicit positive-arousal cognitions and working memory capacity and the interaction between explicit positive-arousal cognitions and working memory capacity predicted unique variance in alcohol use after one month. Implicit positive-arousal cognitions predicted alcohol use after one month more strongly in students with lower levels of working memory capacity, whereas explicit positive-arousal cognitions predicted one-month follow-up alcohol use more strongly in students with higher levels of working memory capacity. This could imply that different intervention methods could be effective for different subgroups of at-risk youth.
implicit cognition; explicit cognition; executive functioning; IAT; adolescence; alcohol use
Despite guidelines and repeated calls from the literature, statistical mediation analysis in youth treatment outcome research is rare. Even more concerning is that many studies that have reported mediation analyses do not fulfill basic requirements for mediation analysis, providing inconclusive data and clinical implications. As a result, after more than five decades of research, it is still largely unknown through which processes youth treatment works and what the effective treatment components are. In this article, we present ten ways in which the use of statistical mediation analysis in youth treatment outcome research may be improved. These ten ways are related both to conceptual and methodological issues. In discussing how youth clinical researchers may optimally implement these directions, we argue that studies should employ the strongest research designs possible. In so doing, we describe different levels of a mediation evidence ladder. Studies on each step of the ladder contribute to an understanding of mediation processes, but the strongest evidence for mediation is provided by studies that can be classified at the highest level. With the help of the ladder of mediation evidence, results from youth mediation treatment outcome research can be evaluated on their scientific as well as clinical impact.
Statistical mediation analysis; Treatment outcome; Youth; Ladder of mediation evidence
Visual-spatial Working Memory (WM) is the most impaired executive function in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Some suggest that deficits in executive functioning are caused by motivational deficits. However, there are no studies that investigate the effects of motivation on the visual-spatial WM of children with- and without ADHD. Studies examining this in executive functions other than WM, show inconsistent results. These inconsistencies may be related to differences in the reinforcement used. The effects of different reinforcers on WM performance were investigated in 30 children with ADHD and 31 non-ADHD controls. A visual-spatial WM task was administered in four reinforcement conditions: Feedback-only, 1 euro, 10 euros, and a computer-game version of the task. In the Feedback-only condition, children with ADHD performed worse on the WM measure than controls. Although incentives significantly improved the WM performance of children with ADHD, even the strongest incentives (10 euros and Gaming) were unable to normalize their performance. Feedback-only provided sufficient reinforcement for controls to reach optimal performance, while children with ADHD required extra reinforcement. Only children with ADHD showed a decrease in performance over time. Importantly, the strongest incentives (10 euros and Gaming) normalized persistence of performance in these children, whereas 1 euro had no such effect. Both executive and motivational deficits give rise to visual-spatial WM deficits in ADHD. Problems with task-persistence in ADHD result from motivational deficits. In ADHD-reinforcement studies and clinical practice (e.g., assessment), reinforcement intensity can be a confounding factor and should be taken into account. Gaming can be a cost-effective way to maximize performance in ADHD.
ADHD; Working memory; Reinforcement; Executive functioning; Motivation; Computer gaming; Cognitive functioning; WM
Both implicit and explicit cognitions play an important role in the development of addictive behavior. This study investigated the influence of a single-session motivational interview (MI) on implicit and explicit alcohol-related cognition and whether this intervention was successful in consequently decreasing alcohol use in at-risk adolescents. Implicit and explicit alcohol-related cognitions were assessed at pretest and one month posttest in 125 Dutch at-risk adolescents ranging in age from 15 to 23 (51 males) with adapted versions of the Implicit Association Test (IAT) and an expectancy questionnaire. Motivation to change, alcohol use and alcohol-related problems were measured with self-report questionnaires, at pretest, at posttest after one month, and at the six-month follow-up. Although the quality of the intervention was rated positively, the results did not yield support for any differential effects of the intervention on drinking behavior or readiness to change at posttest and six-month follow-up. There were indications of changes in implicit and explicit alcohol-related cognitions between pretest and posttest. Our findings raise questions regarding the use of MI in this particular at-risk adolescent population and the mechanisms through which MI is effective.
implicit cognition; explicit cognition; adolescence; alcohol use; motivational interviewing
In this study, the authors compared indirect measures that attempt to quantify the level of marijuana associations among adolescents. They also evaluated whether these various methods overlap or tap different aspects of associative processes that may act in concert to influence marijuana use. Automatic drug-relevant associations were assessed in 121 at-risk youth in continuation high schools in California with the use of a word association index and computer-based, reaction time measures (i.e., Implicit Association Test [IAT] and Extrinsic Affective Simon Task [EAST]). Measures of working memory capacity, sensation seeking, and explicit cognitions also were included in analyses as potential confounders. The word association index and the marijuana IAT excited D measure were significant predictors of marijuana use. The word association index accounted for more variance in marijuana use than did the IAT or EAST measures. Further, confirmatory factor analytic models of the indirect measures of marijuana use revealed a significant moderate correlation between the EAST Excitement and Word Association factors but no significant correlations between the Word Association and IAT factors. These findings suggest that there is some convergence among the different indirect measures, but these assessments also appear to tap different aspects of associative processes. The types of indirect measures evaluated in this work provide information about spontaneous cognitions related to substance use, capturing influences on behavior that are not evaluated with traditional explicit assessments of behavior. Findings from this work add to a growing body of research that implicates the importance of implicit associative processes in risk and health behaviors.
indirect assessment; implicit cognition; marijuana use; word association; IAT
This pilot study demonstrates that it is feasible to administer brief individualized interventions on alternative high school campuses to students who are at risk of substance abuse. Students actively participated in brief motivational interviews and showed some improvement in five of nine outcomes at three-month follow-ups.
Substance use; Adolescents; Motivational interviewing; Brief intervention
Some theories suggest that spontaneously activated, drug-related associations in memory may have a “freer reign” in predicting drug use among individuals with lower working memory capacity. This study evaluated this hypothesis among 145 at-risk youth attending continuation high schools (CHS). This is the first study to evaluate this type of dual-process interaction in the prediction of drug use among a sample of at-risk adolescents. The CHS students completed assessments of drug-related memory associations, working memory capacity, and drug use. Control variables included age, gender, ethnicity, and acculturation. Robust multiple regression using least trimmed squares estimation indicated that there was a significant linear by linear interaction between working memory capacity as assessed with the self-ordered pointing task (SOPT) and drug-related associations (assessed with verb generation and cue-behavior association tasks) in the prediction of alcohol and cigarette use. Consistent with dual-process cognitive theories, drug-related associations in memory predicted drug use more strongly in students with lower levels of working memory capacity. These findings add to the literature implicating the influence of dual cognitive processes in adolescent risk behaviors.
Substance use; adolescents; working memory; and implicit cognition
Socially anxious feelings sharply increase during adolescence and such feelings have been associated with interpretive biases. Studies in adults have shown that interpretive biases can be modified using Cognitive Bias Modification procedures (CBM-I) and subsequent effects on anxiety have been observed. The current study was designed to examine whether the CBM-I procedure has similar effects in adolescents. Unselected adolescents were randomly allocated to either a positive interpretation training (n = 88) or a placebo-control condition (n = 82). Results revealed that the training was successful in modifying interpretations and effects generalized to a new task. The interpretive bias effects were most pronounced in individuals with a threat-related interpretive bias at pre-test. No effects on state anxiety were observed. The current findings are promising with regard to applying bias modification procedures to adolescents, while further research is warranted regarding emotional effects.
Interpretive bias; Cognitive bias modification; Anxiety; Adolescence
Alcohol abuse is associated with a cluster of long-term changes in cognitive processes, as predicted by contemporary models of addiction. In this paper we review evidence which suggests that similar changes may occur during an alcohol binge, and as such they may play an important role in explaining the loss of control over alcohol consumption that occurs during alcohol binges. As a consequence of both acute alcohol intoxication (alcohol ‘priming’ effects) and exposure to environmental alcohol-related cues, we suggest that a number of changes in cognitive processes are likely. These include increased subjective craving for alcohol, increased positive and arousing outcome expectancies and implicit associations for alcohol use, increased attentional bias for alcohol-related cues, increased action tendencies to approach alcohol, increased impulsive decision-making, and impaired inhibitory control over drives and behaviour. Potential reciprocal relationships between these different aspects of cognition during an alcohol binge are discussed. Finally, we discuss the relationship between the current model and existing models of cognitive processes in substance abuse, and we speculate on the implications of the model for the reduction binge drinking and its consequences.
Alcohol; binge drinking; priming; cues; craving; attentional bias; implicit cognition; impulsivity; inhibitory control; outcome expectancies
Alcohol impairs inhibitory control, and it alters implicit alcohol cognitions including attentional bias and implicit associations. These effects are seen after doses of alcohol which do not lead to global impairments in cognitive performance. We review studies which demonstrate that the effects of alcohol on inhibitory control are associated with the ability of alcohol to prime alcohol-seeking behavior. We also hypothesize that alcohol-induced changes in implicit alcohol cognitions may partially mediate alcohol-induced priming of the motivation to drink. Based on contemporary theoretical models and conceptualizations of executive function, impulsivity, and the motivational salience of alcohol-related cues, we speculate on other aspects of cognition that may underlie alcohol’s effects on alcohol seeking. Inconsistencies in existing research and priorities for future research are highlighted, including dose effects and the potential interactions between chronic heavy drinking and the acute effects of alcohol on these cognitive processes.
Inhibitory Control; Attentional Bias; Automatic Alcohol Associations; Priming
This paper contrasts dual-process and personality approaches in the prediction of addictive behaviors and related risk behaviors. In dual-process models, behavior is described as the joint outcome of qualitatively different “impulsive” (or associative) and “reflective” processes. There are important individual differences regarding both types of processes, and the relative strength of both in a specific situation is influenced by prior behavior and state variables (e.g., fatigue, alcohol use). From this perspective, a specific behavior (e.g., alcohol misuse) can be predicted by the combined indices of the behavior-related impulsive processes (e.g., associations with alcohol), and reflective processes, including the ability to refrain from a motivationally salient action. Personality approaches have reported that general traits such as impulsivity predict addictive behaviors. Here we contrast these two approaches, with supplementary analyses on four datasets. We hypothesized that trait impulsivity can predict specific risky behaviors, but that its predictive power disappears once specific behavior-related associations, indicators of executive functioning, and their interaction are entered into the equation. In all four studies the observed interaction between specific associations and executive control (EC) was robust: trait impulsivity did not diminish the prediction of alcohol use by the interaction. Trait impulsivity was not always related to alcohol use, and when it was, the predictive power disappeared after entering the interaction between behavior-specific associations and EC in one study, but not in the other. These findings are interpreted in relation to the validity of the measurements used, which leads to a more refined hypothesis.
impulsivity; dual process models; addiction; alcohol; executive control; developmental psychopathology; personality
Since implicit attitudes toward alcohol play an important role in drinking behavior, a possible way to obtain a behavioral change is changing these implicit attitudes.
This study examined whether a change in implicit attitudes and in drinking behavior can be achieved via evaluative conditioning.
Participants were randomly assigned to an experimental condition and a control condition. In the experimental condition, participants were subjected to an evaluative conditioning procedure that consistently pairs alcohol-related cues with negative stimuli. In the control condition, alcohol-related cues were consistently paired with neutral stimuli during the evaluative conditioning phase. Implicit attitudes, explicit attitudes, and drinking behavior were measured before and after the evaluative conditioning phase.
Following the evaluative conditioning procedure, participants in the experimental condition showed stronger negative implicit attitudes toward alcohol and consumed less alcohol compared to participants in the control condition. However, this effect was only found when the evaluative conditioning task paired alcohol-related cues with general negative pictures, but not when using pictures of frowning faces.
These results demonstrate that evaluative conditioning can effectively change implicit attitudes toward alcohol and also suggest that this procedure can be used to change drinking behavior. Hence, evaluative conditioning may be a useful new intervention tool to combat alcohol misuse.
Alcohol; Drinking behavior; Implicit attitudes; Evaluative conditioning
Heavy alcohol drinking increases the incentive salience of alcohol-related cues. This leads to increased appetitive motivation to drink alcohol as measured by subjective craving and cognitive biases such as attentional bias and approach bias. Although these measures relate to the same construct, correlations between these variables are often very low. Alcohol consumption might not only increase different aspects of appetitive motivation, but also correlations between those aspects.
To investigate the effect of a low alcohol dose on changes in various measures of appetitive motivation.
Materials and methods
Twenty-three heavy social drinkers were tested in 2 sessions, once after receiving an alcohol prime dose and once after receiving a placebo drink. After drink administration, attentional bias was measured with a visual-probe task using concurrent eye movement monitoring. Furthermore, we measured the approach bias with a stimulus response compatibility task and subjective craving with the Desires for Alcohol Questionnaire.
After the alcohol prime dose, participants had higher levels of craving and more pronounced attentional bias (faster reaction times to probes that replaced alcohol rather than control pictures, increased maintenance of gaze on alcohol pictures, and a higher percentage of first eye movements directed toward alcohol pictures). Approach bias was not influenced by the alcohol prime dose. The correlation between attentional bias and approach bias was significantly higher after the alcohol than after the placebo drink.
A low alcohol dose increased most measures of appetitive motivation for alcohol and increased the interrelation between cognitive measures of this construct.
Attentional bias; Approach bias; Eye movements; Craving; Alcohol prime dose
Repeated drug exposure can lead to an approach-bias, i.e. the relatively automatically triggered tendencies to approach rather that avoid drug-related stimuli. Our main aim was to study this approach-bias in heavy cannabis users with the newly developed cannabis Approach Avoidance Task (cannabis-AAT) and to investigate the predictive relationship between an approach-bias for cannabis-related materials and levels of cannabis use, craving, and the course of cannabis use.
Design, settings and participants
Cross-sectional assessment and six-month follow-up in 32 heavy cannabis users and 39 non-using controls.
Approach and avoidance action-tendencies towards cannabis and neutral images were assessed with the cannabis AAT. During the AAT, participants pulled or pushed a joystick in response to image orientation. To generate additional sense of approach or avoidance, pulling the joystick increased picture size while pushing decreased it. Craving was measured pre- and post-test with the multi-factorial Marijuana Craving Questionnaire (MCQ). Cannabis use frequencies and levels of dependence were measured at baseline and after a six-month follow-up.
Heavy cannabis users demonstrated an approach-bias for cannabis images, as compared to controls. The approach-bias predicted changes in cannabis use at six-month follow-up. The pre-test MCQ emotionality and expectancy factor were associated negatively with the approach-bias. No effects were found on levels of cannabis dependence.
Heavy cannabis users with a strong approach-bias for cannabis are more likely to increase their cannabis use. This approach-bias could be used as a predictor of the course of cannabis use to identify individuals at risk from increasing cannabis use.
Approach avoidance task; approach-bias; cannabis; cannabis use disorder; craving; dependence
A potentially powerful predictor for the course of drug (ab)use is the approach-bias, that is, the pre-reflective tendency to approach rather than avoid drug-related stimuli. Here we investigated the neural underpinnings of cannabis approach and avoidance tendencies. By elucidating the predictive power of neural approach-bias activations for future cannabis use and problem severity, we aimed at identifying new intervention targets. Using functional Magnetic Resonance Imaging (fMRI), neural approach-bias activations were measured with a Stimulus Response Compatibility task (SRC) and compared between 33 heavy cannabis users and 36 matched controls. In addition, associations were examined between approach-bias activations and cannabis use and problem severity at baseline and at six-month follow-up. Approach-bias activations did not differ between heavy cannabis users and controls. However, within the group of heavy cannabis users, a positive relation was observed between total lifetime cannabis use and approach-bias activations in various fronto-limbic areas. Moreover, approach-bias activations in the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) independently predicted cannabis problem severity after six months over and beyond session-induced subjective measures of craving. Higher DLPFC/ACC activity during cannabis approach trials, but lower activity during cannabis avoidance trials were associated with decreases in cannabis problem severity. These findings suggest that cannabis users with deficient control over cannabis action tendencies are more likely to develop cannabis related problems. Moreover, the balance between cannabis approach and avoidance responses in the DLPFC and ACC may help identify individuals at-risk for cannabis use disorders and may be new targets for prevention and treatment.
Web-based computer-tailored approaches have the potential to be successful in supporting smoking cessation. However, the potential effects of such approaches for relapse prevention and the value of incorporating action planning strategies to effectively prevent smoking relapse have not been fully explored. The Stay Quit for You (SQ4U) study compared two Web-based computer-tailored smoking relapse prevention programs with different types of planning strategies versus a control group.
To assess the efficacy of two Web-based computer-tailored programs in preventing smoking relapse compared with a control group. The action planning (AP) program provided tailored feedback at baseline and invited respondents to do 6 preparatory and coping planning assignments (the first 3 assignments prior to quit date and the final 3 assignments after quit date). The action planning plus (AP+) program was an extended version of the AP program that also provided tailored feedback at 11 time points after the quit attempt. Respondents in the control group only filled out questionnaires. The study also assessed possible dose–response relationships between abstinence and adherence to the programs.
The study was a randomized controlled trial with three conditions: the control group, the AP program, and the AP+ program. Respondents were daily smokers (N = 2031), aged 18 to 65 years, who were motivated and willing to quit smoking within 1 month. The primary outcome was self-reported continued abstinence 12 months after baseline. Logistic regression analyses were conducted using three samples: (1) all respondents as randomly assigned, (2) a modified sample that excluded respondents who did not make a quit attempt in conformance with the program protocol, and (3) a minimum dose sample that also excluded respondents who did not adhere to at least one of the intervention elements. Observed case analyses and conservative analyses were conducted.
In the observed case analysis of the randomized sample, abstinence rates were 22% (45/202) in the control group versus 33% (63/190) in the AP program and 31% (53/174) in the AP+ program. The AP program (odds ratio 1.95, P = .005) and the AP+ program (odds ratio 1.61, P = .049) were significantly more effective than the control condition. Abstinence rates and effects differed per sample. Finally, the results suggest a dose–response relationship between abstinence and the number of program elements completed by the respondents.
Despite the differences in results caused by the variation in our analysis approaches, we can conclude that Web-based computer-tailored programs combined with planning strategy assignments and feedback after the quit attempt can be effective in preventing relapse 12 months after baseline. However, adherence to the intervention seems critical for effectiveness. Finally, our results also suggest that more research is needed to assess the optimum intervention dose.
Dutch Trial Register: NTR1892; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1892 (Archived by WebCite at http://www.webcitation.org/693S6uuPM)
Smoking relapse prevention; computer tailoring; multiple tailoring; planning strategies