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Biomedical subjects

J W Vlaeyen

Publications and source records attributed to J W Vlaeyen.

At least 19 recordsLinked to original sources

Readiness to adopt the self-management approach to cope with chronic pain in fibromyalgic patients.

The effectiveness of cognitive-behavior therapy aimed at helping patients with the acquisition of self-management skills to cope with pain, is thought to depend partly on the patients' willingness to adopt a self-management approach. Some patients may not believe that self-management will be helpful while others have decided to adopt it and others already apply the self-management skills in their daily lives. The present study explored the concept of 'Readiness to change' in a population of Dutch fibromyalgic patients. A self-report questionnaire was completed by 321 patients. Factor analysis revealed three scales, each assessing the characteristic of one stage of readiness to change, the Precontemplation, Contemplation and Action scale. Firstly, the reliabilities of these scales were 0.61, 0.86 and 0.61, respectively, and only the latter two scales correlated significantly (r=0.14). Secondly, the scales were validated using subscales from the Multidimensional Pain Inventory, beliefs on the credibility of the self-management approach and subscales from the Illness Perception Questionnaire. These subscales explained 5, 22 and 8% of the variance of the scores on the Precontemplation, Contemplation and the Action scales, respectively. Thirdly, on the basis of the three scale scores, over 80% of the fibromialgia patients could be classified into one of five potentially psychological relevant subgroups: Precontemplation, Contemplation, Preparation, Action and Relapse. The data suggest that improvements in operationalizations of the Precontemplation and Action dimensions of readiness to change are needed and that the theoretical foundation of readiness to change needs further development.

Adaptation, Psychological↗

Behavioral treatment for chronic low back pain: a systematic review within the framework of the Cochrane Back Review Group.

STUDY DESIGN: A systematic review of randomized controlled trials. SUMMARY OF BACKGROUND DATA: The treatment of chronic low back pain is not primarily focused on removing an underlying organic disease but at the reduction of disability through the modification of environmental contingencies and cognitive processes. Behavioral interventions are commonly used in the treatment of chronic (disabling) low back pain. OBJECTIVES: To determine whether behavioral therapy is more effective than reference treatments for chronic nonspecific low back pain and which type of behavioral treatment is most effective. METHODS: The authors searched the Medline and PsychLit databases and the Cochrane Controlled Trials Register up to April 1999, and Embase up to September 1999. Also screened were references of identified randomized trials and relevant systematic reviews. Methodologic quality assessment and data extraction were performed independently by two reviewers. The magnitude of effect was assessed by computing a pooled effect size for each domain (i.e., behavioral outcomes, overall improvement, back pain-specific and generic functional status, return to work, and pain intensity) using the random effects model. RESULTS: Only six (25%) studies were high quality. There is strong evidence (level 1) that behavioral treatment has a moderate positive effect on pain intensity (pooled effect size 0.62; 95% confidence interval [CI] 0.25, 0.98), and small positive effects on generic functional status (pooled effect size 0.35; 95% CI: -0.04, 0.74) and behavioral outcomes (pooled effect size 0.40; 95% CI: 0.10, 0.70) of patients with chronic low back pain when compared with waiting-list controls or no treatment. There is moderate evidence (level 2) that a addition of behavioral component to a usual treatment program for chronic low backpain has no positive short-term effect on generic functional status (pooled effect size 0.31; 95% CI: -0.01, 0.64), pain intensity (pooled effect size 0.03; 95% CI:-0.30, 0.36), and behavioral outcomes (pooled effect size 0.19; 95% CI: -0.08, 0.45). CONCLUSIONS: Behavioral treatment seems to be an effective treatment for patients with chronic low back pain,but it is still unknown what type of patients benefit most from what type of behavioral treatment.

Chronic Disease↗

Graded exposure in vivo in the treatment of pain-related fear: a replicated single-case experimental design in four patients with chronic low back pain.

The aim of this investigation was to examine the effectiveness of a graded exposure in vivo treatment with behavioural experiments as compared to usual graded activity in reducing pain-related fears, catastrophising and pain disability in chronic low back pain patients reporting substantial fear of movement/(re)injury. Included in the study were four consecutive CLBP patients who were referred for outpatient behavioural rehabilitation, and who reported substantial fear of movement/(re)injury (Tampa Scale for Kinesiophobia score>40). A replicated single-case cross-over design was used. After a no-treatment baseline measurement period, the patients were randomly assigned to one of two interventions. In intervention A, patients received the exposure first, followed by graded activity. In intervention B, the sequence of treatment modules was reversed. Sixty-three daily measures of pain-related cognitions and fears were recorded with visual analogue scales. Before and after the treatment, the following measures were taken: pain-related fear, pain catastrophising, pain control and pain disability. Using time series analysis on the daily measures of pain-related cognitions and fears, we found that improvements only occurred during the graded exposure in vivo, and not during the graded activity, irrespective of the treatment order. Analysis of the pre-post treatment differences also revealed that decreases in pain-related fear concurred with decreases in pain catastrophising and pain disability, and in half of the cases an increase in pain control. This study shows that the external validity of exposure in vivo also extends to the subgroup of chronic low back pain patients who report substantial fear of movement/(re)injury.

Accidents, Occupational↗

The effects of failure feedback and pain-related fear on pain report, pain tolerance, and pain avoidance in chronic low back pain patients.

The aim of this study was to investigate the influence of non-pain-related failure experiences and pain-related fear on pain report, pain tolerance and pain avoidance in chronic low back pain (CLBP) patients. Moreover, the mediating and moderating role of negative affectivity (trait-NA) in the relationship between failure experiences and pain was examined. Seventy-six patients were divided into high and low pain-related fear groups and within each group they were randomly assigned to the failure or success feedback condition. In the first part of the study patients completed a 'social empathy test' and experimenter 1 subsequently delivered false failure or success feedback. A second experimenter, who was blind for the condition, subsequently administered two lifting tasks in order to obtain measures of pain report, tolerance and avoidance. Failure feedback did have an effect on pain avoidance but unexpectedly, and not as hypothesized, pain avoidance was reduced instead of enhanced. With regard to pain report and pain tolerance similar patterns were found, but these were not statistically significant. The effect of failure feedback on pain avoidance was moderated by trait-NA. Only in the subgroup of patients who scored low on trait-NA did failure feedback decrease pain avoidance. State-NA did not mediate the effects of feedback. In line with previous findings, pain-related fear resulted in lower pain tolerance. Moreover, this study was the first to show that pain-related fear predicted higher pain report in CLBP patients. Pain-related fear did not predict pain avoidance when pre-lifting pain and gender were controlled for. Finally, pre-lifting pain turned out to be the strongest predictor with regard to all pain measures. The role of pain-related fear and unexpected findings with regard to feedback are discussed as well as some clinical implications.

Adaptation, Psychological↗

Physical activity in daily life in patients with chronic low back pain.

OBJECTIVES: To evaluate disuse (ie, a decreased daily physical activity level) in patients with chronic low back pain (LBP) and to evaluate the construct validity of accelerometry for measuring physical activity in daily life. DESIGN: Case-control study in a cross-sectional design; comparison of accelerometry to the criterion standard (doubly labeled water technique). SETTING: Normal daily living (unrestricted by the measurement devices). PATIENTS: Thirteen patients with chronic nonspecific LBP and 13 age- and gender-matched healthy controls. MAIN OUTCOME MEASURES: Physical activity in daily life, expressed as whole-body acceleration measured with a triaxial accelerometer (Tracmor), and as the ratio between average daily metabolic rate (ADMR), measured by the doubly labeled water technique, and resting metabolic rate (RMR), measured by the ventilated hood. Both techniques were used simultaneously for 14 days. RESULTS: Mean physical activity level in patients and controls did not differ significantly. The correlation between the Tracmor and ADMR and RMR was .72 (p < .01). CONCLUSIONS: Decreased physical activity levels in this sample of chronic LBP patients was not confirmed. The Tracmor is a valid instrument for measuring daily activity in LBP patients.

Activities of Daily Living↗

Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment.

OBJECTIVE: The aim of the current study was to examine the relation between catastrophizing and pain intensity, pain-related disability, and psychological distress in a group of patients with chronic pain, controlling for the level of physical impairment. Furthermore, it was examined whether these relations are the same for three subgroups of chronic pain patients: those with chronic low back pain, those with chronic musculoskeletal pain other than low back pain, and those with miscellaneous chronic pain complaints, low back pain and musculoskeletal pain excluded. DESIGN: Correlational, cross-sectional. PATIENTS AND SETTING: Participants in this study were 211 consecutive referrals presenting to a university hospital pain management and research center, all of whom had a chronic pain problem. RESULTS: Overall, chronic pain patients who catastrophize reported more pain intensity, felt more disabled by their pain problem, and experienced more psychological distress. Regression analyses revealed that catastrophizing was a potent predictor of pain intensity, disability, and psychological distress, even when controlled for physical impairment. No fundamental differences between the three subgroups were found in this respect. Finally, it was demonstrated that there was no relation between physical impairment and catastrophizing. CONCLUSIONS: It was concluded that for different subgroups of chronic pain patients, catastrophizing plays a crucial role in the chronic pain experience, significantly contributing to the variance of pain intensity, pain-related disability, and psychological distress. These relations are not confounded by the level of physical impairment. Some clinical implications of the results are discussed. Finally, the authors concluded that these results support the validity of a cognitive-behavioral conceptualization of chronic pain-related disability.

Adult↗

Anxiety sensitivity and fear of pain in children.

Associations among scores on scales of anxiety sensitivity and trait anxiety and a fear of pain questionnaire were examined for 118 children. Analysis showed that anxiety sensitivity was positively and substantially related to fear of pain in the children. Furthermore, the data suggested anxiety sensitivity to be a better predictor of fear of pain than trait anxiety.

Anxiety Disorders↗

Behavioral treatment for chronic low back pain: a systematic review within the framework of the Cochrane Back Review Group.

STUDY DESIGN: A systematic review of randomized controlled trials. SUMMARY OF BACKGROUND DATA: The treatment of chronic low back pain is not primarily focused on removing an underlying organic disease but at the reduction of disability through the modification of environmental contingencies and cognitive processes. Behavioral interventions are commonly used in the treatment of chronic (disabling) low back pain. OBJECTIVES: To determine whether behavioral therapy is more effective than reference treatments for chronic nonspecific low back pain and which type of behavioral treatment is most effective. METHODS: The authors searched the Medline and PsychLit databases and the Cochrane Controlled Trials Register up to April 1999, and Embase up to September 1999. Also screened were references of identified randomized trials and relevant systematic reviews. Methodologic quality assessment and data extraction were performed independently by two reviewers. The magnitude of effect was assessed by computing a pooled effect size for each domain (i.e., behavioral outcomes, overall improvement, back pain-specific and generic functional status, return to work, and pain intensity) using the random effects model. RESULTS: Only six (25%) studies were high quality. There is strong evidence (level 1) that behavioral treatment has a moderate positive effect on pain intensity (pooled effect size 0.62; 95% confidence interval [CI] 0. 25, 0.98), and small positive effects on generic functional status (pooled effect size 0.35; 95% CI: 0.04, 0.74) and behavioral outcomes (pooled effect size 0.40; 95% CI: 0.10, 0.70) of patients with chronic low back pain when compared with waiting-list controls or no treatment. There is moderate evidence (level 2) that a addition of behavioral component to a usual treatment program for chronic low backpain has no positive short-term effect on generic functional status (pooled effect size 0.31; 95% CI: 0.01, 0.64), pain intensity (pooled effect size 0.03; 95% CI: 0.30,0.36), and behavioral outcomes (pooled effect size 0.19; 95% CI: 0.08, 0.45). CONCLUSIONS: Behavioral treatment seems to be an effective treatment for patients with chronic low back pain,but it is still unknown what type of patients benefit most from what type of behavioral treatment.

Analgesics↗

Behavioural treatment for chronic low back pain.

BACKGROUND: The treatment of chronic low back pain is not primarily focused on removing an underlying organic pathology, but at the reduction of disability through the modification of environmental contingencies and cognitive processes. Behavioural interventions are commonly used in the treatment of chronic (disabling) low back pain. OBJECTIVES: The objective of this systematic review was to determine if behavioural therapy is more effective than reference treatments for chronic non-specific low back pain, and which type of behavioural treatment is most effective. SEARCH STRATEGY: We searched the Medline, PsycLit databases, and the Cochrane Controlled Trials Register up to April 1999, Embase up to September 1999. We also screened references of identified randomised trials and relevant systematic reviews. SELECTION CRITERIA: Only randomised trials on any type of behavioural treatment for non-specific chronic low back pain were included. DATA COLLECTION AND ANALYSIS: Methodological quality assessment and data extraction was done by two reviewers independently. The magnitude of effect was assessed by computing a pooled effect size for each domain (i.e., behavioural outcomes, overall improvement, back pain specific and generic functional status, return to work, and pain intensity) using the random effects model. MAIN RESULTS: Only 6 studies (25%) were high quality. There is strong evidence (level 1) that behavioural treatment has a moderate positive effect on pain intensity (pooled effect size 0.62; 95% CI 0.25, 0.98), and small positive effects on generic functional status (pooled effect size 0.35; 95% CI -0.04, 0.74) and behavioural outcomes (pooled effect size 0.40; 95% CI 0.10, 0.70) of chronic low back pain patients when compared to waiting list controls or no treatment. There is moderate evidence (level 2) that an additional behavioural component to a usual treatment program for chronic low back pain has no positive short-term effect on generic functional status (pooled effect size 0.31; 95% CI - 0.01, 0.64), pain intensity (pooled effect size 0.03; 95% CI - 0.30, 0. 36) and behavioural outcomes (pooled effect size 0.19; 95% CI - 0.08, 0.45). REVIEWER'S CONCLUSIONS: Behavioural treatment seems to be an effective treatment for chronic low back pain patients, but it is still unknown what type of patients benefit most from what type of behavioural treatment.

Behavior Therapy↗

The cost diary: a method to measure direct and indirect costs in cost-effectiveness research.

From a societal perspective long-term clinical trials or follow-up studies should preferably not only include an evaluation of the health effect for the patient, but also an economic evaluation. In order to yield comprehensive medical and nonmedical resource use data, we at least partly depend on respondents' recall for collecting these costing data. A patient cost diary was developed in order to estimate total resource use, expenses, and lost production due to illness and treatment. We applied the cost diary in two randomized clinical trials evaluating the cost-effectiveness of behavioral rehabilitation in 205 fibromyalgia and chronic low back pain patients. The use of the diary was evaluated, studying the feasibility, the influence of the period of data collection on the results, and some aspects of validity. Eighty-five percent of the patients completed at least one diary and in total 68% of the diaries were returned. Although the results for the three alternative periods of data collection (keeping the diary 1 week every month, 2 weeks every 2 months, or a full year) were not significantly different, they were only moderately correlated. Finally, self-reported specialist care contacts were generally in agreement with data from an insurance company. However, for physiotherapy contacts there were differences between the self-reported and insurance data. This study shows how the cost diary might be used successfully in cost-effectiveness studies.

Cost-Benefit Analysis↗

Does failure hurt? The effects of failure feedback on pain report, pain tolerance and pain avoidance.

In this study an experiment was conducted to examine whether failure experiences have an effect on pain report, pain tolerance and pain avoidance. Furthermore, it was investigated if negative affectivity (NA) affected the impact of failure feedback on pain report, either as a mediator, in the case of negative state affect, or as a moderator when NA as a personality trait was considered. Fifty-four healthy female volunteers were included and randomly assigned to one of three conditions: (1) failure feedback; (2) success feedback; (3) neutral control task. After the manipulation, subjects were given a cold pressor task in order to obtain pain measures. Regarding the effects of failure feedback on pain report, it was found that, in comparison with success feedback, failure feedback led to increased pain report. With regard to pain tolerance, pain was tolerated for longer when preceded by success feedback than when preceded by failure feedback. Differences between failure and control conditions did not reach significance. With regard to pain avoidance, no differences between the conditions were found. The hypothesized mediating role of negative state affect was not found. Though in the hypothesized direction, no significant effect was found for NA-trait moderating the influence of failure on pain. The discussion focuses on a number of research questions that remain to be answered, and the clinical relevance of the effects of failure and success experiences on pain report and pain tolerance.

Adolescent↗

Behavioral-graded activity compared with usual care after first-time disk surgery: considerations of the design of a randomized clinical trial.

OBJECTIVE: To present the design of a trial on the effectiveness of a behavioral-graded activity model. DESIGN: Randomized clinical trial. PATIENTS: Patients undergoing first-time lumbar disk surgery who still have low-back pain at the 6-week neurosurgical consultation. INTERVENTIONS: A patient-tailored behavioral-graded activity program that is based on operant therapy. The key elements of this program are baseline measurements, goal-setting, and time-contingency. This program is compared with usual care in physiotherapy, which is pain-contingent. OUTCOME MEASURES: Primary measures are the patient's global impression of the effect and their functional status. Secondary measures are kinesiophobia, catastrophizing, pain, main complaint, range of motion, and relapses. The direct and indirect costs will also be assessed. The effect measures are rated before randomization and 3, 6, and 12 months later. DISCUSSION: Several trials have been conducted on the effectiveness of behavioral treatments. Subjects were always patients with chronic low-back pain. In this trial, we apply such a treatment in patients after first-time disk surgery in a primary care setting.

Adaptation, Psychological↗

Effect of butorphanol tartrate on shock-related discomfort during internal atrial defibrillation.

BACKGROUND: In patients with atrial fibrillation, intracardiac atrial defibrillation causes discomfort. An easily applicable, short-acting analgesic and anxiolytic drug would increase acceptability of this new treatment mode. METHODS AND RESULTS: In a double-blind, placebo-controlled manner, the effect of intranasal butorphanol, an opioid, was evaluated in 47 patients with the use of a step-up internal atrial defibrillation protocol (stage I). On request, additional butorphanol was administered and the step-up protocol continued (stage II). Thereafter, if necessary, patients were intravenously sedated (stage III). After each shock, the McGill Pain Questionnaire was used to obtain a sensory (S), affective (A), evaluative (E), and total (T) pain rating index (PRI) and a visual analogue scale analyzing pain (VAS-P) and fear (VAS-F). For every patient, the slope of each pain or fear parameter against the shock number was calculated and individual slopes were averaged for the placebo and butorphanol group. All patients were cardioverted at a mean threshold of 4.4+/-3.3 J. Comparing both patient groups for stage II, the mean slopes for PRI-T (P=0.0099), PRI-S (P=0.019), and PRI-E (P=0.015) became significantly lower in the butorphanol group than in the placebo group. Comparing patients who received the same shock intensity ending stage I and going to stage II, in those patients randomized to placebo the mean VAS-P (P=0.023), PRI-T (P=0. 029), PRI-S (P=0.030), and PRI-E (P=0.023) became significantly lower after butorphanol administration. CONCLUSIONS: During a step-up internal atrial defibrillation protocol, intranasal butorphanol decreased or stabilized the value of several pain variables and did not affect fear. Of the 3 qualitative components of pain, only the affective component was not influenced by butorphanol. The PRI evaluated pain more accurately than the VAS.

Administration, Intranasal↗

Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability.

There is growing evidence for the idea that in back pain patients, pain-related fear (fear of pain/physical activity/(re)injury) may be more disabling than pain itself. A number of questionnaires have been developed to quantify pain-related fears, including the Fear-Avoidance Beliefs Questionnaire (FABQ), the Tampa Scale for Kinesiophobia (TSK), and the Pain Anxiety Symptoms Scale (PASS). A total of 104 patients, presenting to a rehabilitation center or a comprehensive pain clinic with chronic low back pain were studied in three independent studies aimed at (1) replicating that pain-related fear is more disabling than pain itself (2) investigating the association between pain-related fear and poor behavioral performance and (3) investigating whether pain-related fear measures are better predictors of disability and behavioral performance than measures of general negative affect or general negative pain beliefs (e.g. pain catastrophizing). All three studies showed similar results. Highest correlations were found among the pain-related fear measures and measures of self-reported disability and behavioral performance. Even when controlling for sociodemographics, multiple regression analyses revealed that the subscales of the FABQ and the TSK were superior in predicting self-reported disability and poor behavioral performance. The PASS appeared more strongly associated with pain catastrophizing and negative affect, and was less predictive of pain disability and behavioral performance. Implications for chronic back pain assessment, prevention and treatment are discussed.

Adult↗

Patient utilities in chronic musculoskeletal pain: how useful is the standard gamble method?

The main goal of current pain management approaches is to increase the patients' quality of life by improving pain coping skills and by reducing the levels of disability in daily life, often despite persistent pain. Direct measurement of quality of life is of crucial importance in economic evaluation research, in which not only is the estimation of financial costs and benefits included, but so is the evaluation of costs and benefits in terms of changes in health states. The purpose of this study is to compare the psychometric qualities of two instruments for assessing patients' utilities, the rating scale (RS) and the standard gamble (SG). Such instruments are designed for their application in economic evaluation research, but have seldomly been used in chronic pain trials. Both methods provide a single measure between 0 and 1. The relationship between these utility measures and descriptive and domain-specific quality of life measures was examined in 133 fibromyalgia patients and 148 patients with chronic non-specific low back pain. Mean utility score at baseline was 0.43 with the RS and 0.78 for the SG. The correlation between both methods was found to be poor (r = 0.21). Both measures appeared to be fairly stable in a 2-week test-retest period (intra class correlation coefficient (ICC) = 0.74 and 0.77). Scores on the description of patient's own health on six domains, global assessment of change and domain specific measures correlated moderately with the RS scores and low with the SG. Multiple regression analyses demonstrated that 32% of the variance in RS values and only 13% of the variance in SG utilities could be explained by domain-specific measures. These results suggest an acceptable construct validity for the RS but insufficient construct validity for the SG. Valuations of ones own health appear only partially to be related to the assessment of the pain-specific measures and measures of distress. It can be concluded that the RS and domain-specific measures assess partly different, but nevertheless complementary aspects of health-related quality of life. It is therefore recommended to include in economic evaluation studies both domain-specific measures and valuation measures. Finally, in chronic musculoskeletal pain patients, RS scores were found to be more responsive in detecting significant changes in preferences than SG scores. For use in patients with chronic musculoskeletal pain, the RS is preferred to the SG for establishing accurate decisions about the impact of new interventions on their health outcomes.

Activities of Daily Living↗

Chronic low-back pain: what does cognitive coping skills training add to operant behavioral treatment? Results of a randomized clinical trial.

This study examined the supplemental value of a cognitive coping skills training when added to an operant-behavioral treatment for chronic low-back pain patients. The complete treatment package (OPCO) was compared with an operant program + group discussion (OPDI) and a waiting-list control (WLC). After the WL period, the WLC patients received a less protocolized operant program usually provided in Dutch rehabilitation centers (OPUS). Regression analyses showed that, compared with WLC, both OPCO and OPDI led to less negative affect, higher activity tolerance, less pain behavior, and higher pain coping and pain control. At posttreatment, OPCO led to better pain coping and pain control than OPDI. Calculation of improvement rates revealed that OPCO and OPDI had significantly more improved patients than OPUS on all the dependent variables. The discussion includes findings regarding treatment credibility, compliance, and contamination bias.

Adaptation, Psychological↗

Fear of movement/(re)injury, avoidance and pain disability in chronic low back pain patients.

Chronic pain syndromes such as chronic low back pain are responsible for enormous costs for health care and society. For these conditions a pure biomedical approach often proves insufficient. Numerous studies have shown that there is little direct relationship between pain and disability and suggest that the biopsychosocial approach offers the foundations for a better insight in how pain can become a persistent problem. The main assumption is that pain and pain disability are not only influenced by organic pathology, if found, but also by psychological and social factors. In this contribution, a behavioural analysis of chronic musculoskeletal pain will be discussed, with special attention to the role of pain-related fear in the development and maintenance of chronic pain disability, and the behavioural rehabilitation perspective of chronic pain management.

Avoidance Learning↗

Health economic assessment of behavioural rehabilitation in chronic low back pain: a randomised clinical trial.

The aim of this cost-effectiveness study was to compare a combined operant programme plus cognitive/relaxation programme with an operant programme plus attention-control and to compare both programmes with a waiting-list control group and with operant rehabilitation provided, as usual, by the same rehabilitation centre. One hundred and forty eight patients with chronic low back pain were randomly assigned to the different conditions. The economic endpoints were the costs of the programme and other health care utilisation, costs for the patient, and indirect costs associated with production losses due to low back pain. The effects were measured in terms of global assessment of change and utilities, using rating scale and standard gamble methods. The 3-year study determined that adding a cognitive component to an operant treatment did not lead to significant differences in costs and improvement in quality of life when compared with the operant treatment alone. Compared with the common individual rehabilitation therapy it can be concluded that the same effects can be reached at the same or lower costs with a shorter, more intense standardised group programme. The operant treatment alone is more effective than providing no treatment in the waiting-list control group.

Adult↗