Treatment dropout is one of the most crucial issues that a therapist has to face on a daily basis. The negative effects of premature termination impact the client who is usually found to demonstrate poorer treatment outcomes. This meta-analysis reviewed and systematically examined dropout effects of Acceptance and Commitment Therapy (ACT) as compared to other active treatments. The goals of this study were to compare treatment dropout rates and dropout reasons, examine the influence of demographic variables and identify possible therapy moderators associated with dropout.
The current meta-analysis reviewed 76 studies of ACT reporting dropout rates for various psychological and health-related conditions.
Across reviewed studies (N = 76), the overall weighted mean dropout rate was 17.95% (ACT = 17.35% vs. comparison conditions = 18.62%). Type of disorder, recruitment setting and therapists’ experience level were significant moderators of dropout. The most frequently reported reasons for dropout from ACT were lost contact, personal and transportation difficulties, whereas for comparative treatments they were lost contact, therapy factors and time demands.
Given that most moderators of influence are not amenable to direct changes by clinicians, mediation variables should also be explored. Overall, results suggest that ACT appears to present some benefits in dropout rates for specific disorders, settings and therapists.
There was no difference in dropout rate between ACT and control conditions (17.35% vs.18.62%). Significant moderators were client disorder, therapists’ experience level and recruitment and setting. Comparison condition frequently reported therapy related dropout factors, suggesting that ACT may be a more acceptable option.
Acceptance and Commitment Therapy (ACT), is a so-called third wave Cognitive Behavior Therapy (CBT) and has been applied successfully to treat numerous problems and disorders (
Treatment outcomes and effectiveness, however, are affected not only by the specific treatment provided but also by other factors such as premature termination/dropout or non-completion of the specified interventions (
Reviews and meta-analyses of this phenomenon focus on examining first the rates of dropout and, secondly, variables associated with its occurrence.
This study aims to examine the dropout phenomenon in ACT (compared to other active interventions) because of ACT’s emphasis on connecting clients with their deeply held values and through this process to motivate them towards behavior change. If ACT is successful in mobilizing individuals via the treatment process, we expect that this would prevent premature termination and thus ACT would result in lower dropout rates compared to other interventions. To date, only one meta-analysis on dropout has included ACT (
A minority of patients may drop out because they improved or met their goals; however numerous individuals drop out because of a problem with the treatment or therapists or for other unforeseen circumstances. Specifically, proposed problems or reasons associated with increased dropout rates include: client demographic characteristics (e.g., younger age, female gender, low socioeconomic status;
Researching these reasons is difficult as variables and methods vary widely depending on the study and its focus, the population studied, the treatment setting or the treatment offered (
Interestingly, very little attention has been given to the timing during treatment when premature termination occurs and most studies do not even report this information. Some have proposed that the first two sessions are critical for premature termination, given that most dropouts (70%) occur at this point, making it a critical period to successfully engage the client in treatment (
The purpose of this study is to examine dropout rates, dropout reasons’ associated factors, and potential moderators of dropout, in ACT compared to active comparison conditions. The goals of this study were to: (i) compare treatment dropout rate and timing between ACT and other active treatments; (ii) examine the influence of demographic variables such as age, gender, treatment setting, race, education, duration of treatment, ethnicity and diagnosis on dropout; (iii) identify possible therapy-associated moderators of dropout; and (iv) examine timing and possible reasons for dropout.
This review was registered in the International Prospective Register of Systematic Reviews (see
The literature search was conducted using the computerized literature databases Google Scholar, EBSCOhost (Academic Search Ultimate, Medline, Psychology and Behavioral Sciences Collection, PsycARTICLES, PsychInfo, OpenDissertations) and Science Direct (until June 2018) with the following keywords based on title: “Acceptance and Commitment Training”, “Acceptance-based behavior therapy”, “ACT-based”, “Experiential avoidance”, “Psychological flexibility”, “RFT-based”, “CBS-based”, “Third wave CBT therapies” “Acceptance and Commitment Therapy”, and “ACT”; alone first and then also combined with the terms “drop out” or “dropout” or “discontinuation” or “outcome” or “premature termination” or “termination”. The reference lists of all identified articles were examined for additional potentially eligible studies, as well as existing meta-analyses and reviews. A request for unpublished studies was sent to the Acceptance and Commitment Therapy (ACT) listserv (
Identification and selection of the included studies was performed by the second author, a clinical psychology doctoral student, who was first trained and instructed in the procedure of conducting meta-analysis by the first and last authors. Everything was checked by the first author. The last three authors all have experience in meta-analysis and served to check all steps taken in the process of this study.
This study includes all published and unpublished (e.g., dissertation) Acceptance and Commitment Therapy studies that included dropout information and met the following criteria. Studies were included if they: (1) were in English, (2) reported dropout rates after beginning psychotherapy or reported no dropouts (i.e., all participants completed treatment), and (3) used an active comparison condition. Studies were excluded if: (a) data originated from the same sample as another included study (so as to avoid violating the meta-analytic assumption of data independence); (b) information to calculate effect sizes was lacking and contact with authors was not possible; and (c) case studies.
The literature search resulted in 4399 articles in total. After screening the titles and abstracts, and following the examination of the full papers, 76 studies met all aforementioned inclusion criteria and were retained for analysis (see
Flow chart of information from identification to inclusion of studies in this review.
Treatment dropout was defined as the percentage of patients who began treatment, but according to the author(s) dropped out prematurely, thus utilizing the author(s)’ definition. For reliability and validity purposes we included only studies that reported dropout rates during treatment and not prior to treatment initiation.
Participant, therapist, treatment and study characteristics were coded (see
Participant characteristics | |
---|---|
Client disorder | Anxiety disorder (including social phobia, public speaking anxiety, generalized anxiety disorder and obsessive compulsive disorder), depression, substance abuse or dependence, chronic pain (including fibromyalgia, osteoarthritis and headaches), eating pathology/disorder (including diabetes, obesity, weight problems and eating disorders), health conditions and chronic illnesses (i.e. Parkinson’s disease, multiple sclerosis, brain injury, cancer and HIV), smoking, other health problems (stress, distress, physical activity, tinnitus, procrastination and sickness absence) and severe psychopathology (including borderline personality disorder, treatment resistant and psychosis) |
Gender | Percentage of female participants in each study |
Age | Average age in years of participants in each sample |
Race | Percentage of White (including Caucasian, Australian and European), Black (including African American) and other (Hispanic, Latino, Asian American/ Pacific Islander, Native American, Alaskan American and American Indian/ Alaskan native) |
Marital status | Percentage of participants who were single (non-married, never married, divorced, separated or widowed) vs. married (cohabiting, living with partner/spouse/family or in a relationship) |
Employment | Percentage of participants who were working, either full-time or part-time |
Years of education | Participants’ average number of completed education years in each study. In cases where the mean number of education in years was not provided, we calculated this based on the data reported. |
Population | Adults or children and adolescents |
Treatment variables | |
Comparison condition | CBT, Treatment as Usual (TAU; studies in which TAU consisted of only administrating medication were coded as medication only), medication only (i.e., Medication Treatment as Usual plus Enhanced Assessment and Monitoring, Recommended Pharmacological Treatment, Specialty Medical Management, Methadone maintenance, Selective Serotonin Reuptake Inhibitors, Medical Treatment as Usual, Nicotine Replacement Treatment and Bupropion Regimen), other active treatment (i.e., Narcotics Anonymous, Applied Behavior Analysis, smokefree.gov, online discussion forum, usual care, counseling services, Workplace Dialogue Intervention, Present-Centered Therapy, physical exercise, Drug Counseling, Tinnitus Retraining Therapy and Expressive writing), component of CBT (including Progressive Relaxation Training, Systematic Desensitization, Applied Relaxation, Cognitive Therapy, Stress Inoculation Training, Relaxation Training) and education only (education, Befriending, Pedometer-based walking program) |
Treatment status | Providing any treatment/training to the comparison condition or not |
Length of intervention | Total length of treatment in weeks (in cases where months were reported, each month was calculated to equal 4 weeks) |
Length of intervention in sessions | Total number of treatment sessions |
Hours of intervention | The overall duration of intervention in hours |
Format of treatment | Individual, self-help (including web-based and online format), group, or combination (group & individual) |
Treatment setting | Outpatient, inpatient or self-help (including web-based and online format) |
Description of treatment setting | University affiliated clinic (psychology department training clinic and university counseling center), outpatient clinic affiliated with a hospital or medical school, public/community outpatient clinic, research/specialty clinic, private outpatient clinic/practice, therapy took place at participant’s home (i.e., web-based/online intervention or self-help) and inpatient or residential treatment |
Treatment provider variables | |
Experience level of ACT therapists | Master level therapists or doctoral students/interns/residents, doctoral level or licensed therapists, mix of doctoral level, student trainees, and others (e.g., licensed clinicians, psychiatrists, social workers, psychiatric nurses), no therapists (i.e., for online/web-based or self-help formats), mix of different psychologist levels and non-psychologists (e.g. drug staff, alcohol counselor, physician, psycho-pharmacologist) |
Experience level of therapists in comparison groups. | Master level therapists or doctoral students/interns/residents, doctoral level or licensed therapists, mix of doctoral level, student trainees, and others (e.g., licensed clinicians, psychiatrists, social workers, psychiatric nurses), no therapists (i.e. it was applicable for online/web-based or self-help formats), mix of different psychologist levels, psychiatrists and non-psychologists (e.g. drug staff, alcohol counselor, physician, psycho-pharmacologist). |
Study variables | |
Definition of dropout | Failed to complete treatment/discontinued treatment/left before treatment end, or refused to return to treatment, failed to attend all sessions, failed to submit pre and post treatment data and attended less than or equal to either: 25-40%, 50-75% or 76-90% of total sessions |
Study type | Efficacy (i.e., studies that emphasize internal validity) or effectiveness (i.e., emphasize external validity of the experimental design). If the study type was not specifically reported, efficacy was coded as studies utilizing: (a) strict exclusion criteria, (b) careful pre-selection of clients, (c) treatment following a strict protocol and was more controlled than effectiveness studies, (d) randomization of participants to treatments, and/or (e) therapists receiving training before and supervision during the study |
Year of publication | |
Region | In which each study was conducted |
The second and third authors coded all variables separately and these were checked for accuracy by the first authors. There was a 95% agreement rate between coders with disagreements resolved via a consensus among the authors (for further coding details contact the authors).
First, the dropout rate for each study condition (ACT vs. comparison group) was calculated (i.e., the total number of patients who dropped out of each treatment group, out of the total number of patients included in each group). Then, the weighted average dropout rate (i.e., weighted dropout rate for each study condition based on the total number of patients included in the study) was computed for each of the 76 included studies. The number of participants dropped from each group was included in the Comprehensive Meta-Analysis software (CMA; version 2.0, Biostat, Englewood, NJ), along with the sample size of each group (treatment and comparison). Odds ratio was then computed. Odds ratios higher than 1 suggest that dropout rates are higher in the intervention versus the comparison condition (i.e., comparison group is better).
Random-effects models were used to estimate the effect size of rate ratio in the included studies, as the assumptions of random-effect models suggests that study characteristics influence the true effect of treatments, and that sampling error varies between studies (
First, an unconditioned model without having any predictors or moderators was calculated using CMA, in order to detect the general rate ratio of dropouts between treatment and comparison conditions. In order to examine if the results of the general model were subject to biases related to the publication of studies with favorable outcomes, publication bias was investigated by assessing the asymmetries evident in a funnel plot, with the Egger’s regression test (
All identified studies were included in the meta-analysis; no structured qualitative assessment of the reviewed articles was performed. The large majority of included studies employed a randomized controlled trial design, or at least a controlled trial design. This suggests that all studies are at least of a moderate methodological quality (
See
Study & Region | Disorder | N | Control group(s) | % dropout ACT | % dropout control group(s) | Mean Age | % female | Setting | Format | Tx weeks |
---|---|---|---|---|---|---|---|---|---|---|
Cancer | 36 | CBT | 0.00 | 16.66 | NI | 100 | Ο | G | NI | |
CP | 101 | MS | 43.40 | 29.17 | 83 | 78 | O | G | 9 | |
Anxiety | 128 | CBT | 35.09 | 32.39 | 38 | 52 | O | Ind | 12 | |
GAD | 51 | CBT | 12.00 | 23.08 | 36 | 67 | O | G | 6 | |
Substance Abuse | 60 | Narcotics Anonymous | 20.00 | 15.00 | 27 | NI | O | I | 12 | |
Intellectual Disability | 34 | ABA | 10.00 | 11.11 | 38 | 77 | O | G | 3 | |
Smoking | 222 | Smokefree.gov | 45.95 | 46.85 | 45 | 62 | S | S | 3 | |
CP | 76 | Online Discussion Forum | 15.79 | 15.79 | 49 | 59 | S | S | 7 | |
Physical activity | 54 | Education | 20.00 | 5.26 | 23 | 100 | O | G | 3 | |
Treatment resistant | 61 | TAU-CBT | 13.33 | 22.58 | 43 | 67 | O | G | 16 | |
Osteoarthritis | 31 | Usual Care | 31.25 | 0.00 | 67 | 71 | O | G | 6 | |
SP | 87 | CBT | 20.69 | 36.36 | 28 | 46 | O | Ind | 12 | |
Smoking | 70 | Other active treatment | 2.86 | 5.71 | 30 | 0 | O | Ind | 8 | |
Stress | 113 | TAU | 28.99 | 29.55 | 25 | 79 | O | G | 6 | |
Anxiety | 45 | HAB | 23.81 | 20.83 | 32 | 80 | O | G | 6 | |
Sickness Absence | 352 | WDI | 7.32 | 12.90 | 46 | 78 | O | Ind | 10 | |
Distress | 107 | SIT | 13.51 | 10.81 | 39 | 72 | O | G | 3 | |
Anxiety | 101 | CT | 33.90 | 42.20 | 28 | 80 | O | Ind | M = 15.27 | |
Obesity | 128 | SBT | 9.46 | 20.37 | 46 | 100 | O | G | 40 | |
Psychosis | 40 | TAU | 5.26 | 4.76 | 40 | 36 | Inp | Ind | 3 | |
Depression | 13 | MTAU | 16.66 | 42.86 | 50 | 54 | O | Ind | 16 | |
Parkinson | 46 | TAU | 13.04 | 8.70 | 63 | 39 | O | G | 6 | |
Smoking | 76 | NRT | 36.40 | 38.10 | 43 | 59 | O | G & Ind | 7 | |
Smoking | 303 | BP | 33.08 | 46.82 | 46 | 59 | O | G & Ind | 10 | |
Anxiety | 25 | TCBT | 0.00 | 8.33 | 24 | 73 | O | Ind | 1 | |
Cancer | 66 | BA | 29.41 | 22.73 | 52 | 92 | O | G | 12 | |
Type 2 diabetes | 81 | Education | 0.00 | 0.00 | 51 | 47 | O | G | 1 | |
Anxiety | 193 | CBT | 20.59 | 9.52 | 11 | 58 | O | G | 10 | |
Polysubstance-Abusing Opiate Addicts | 124 | MM, ITSF | 45.24 | 24.00 | 42 | 51 | O | G & Ind | 16 | |
Depression | 38 | TAU | 13.63 | 31.25 | 15 | 71 | O | Ind | NI | |
Anxiety | 81 | AR | 25.00 | 21.95 | 65 | 33 | O | Ind | 16 | |
Smoking | 81 | CBT | 37.21 | 23.68 | 42 | 64 | O | G | 7 | |
Tinnitus | 99 | CBT | 2.86 | 6.25 | 49 | 43 | S | S | 8 | |
ED | 140 | TAU | 15.15 | 8.11 | 27 | 100 | Inp | G | M = 3.91 | |
Pain | 60 | AR | 0.00 | 16.66 | 40 | 73 | O | G | 12 | |
Treatment resistant | 40 | CBT | 15.00 | 40.00 | 44 | 60 | O | G | 16 | |
SAD | 137 | CBT | 30.19 | 39.62 | 35 | 54 | O | G | 12 | |
Distress | 160 | PCT | 33.75 | 30.00 | 34 | 20 | O | Ind | 12 | |
Substance Use | 50 | CBT | 0.00 | 0.00 | 33 | 100 | NI | G | 16 | |
Psychosis | 28 | TAU | 14.29 | 42.86 | 42 | 39 | O | G | 2 | |
Weight loss | 162 | CBT | 16.05 | 13.58 | 50 | 85 | O | G | 52 | |
Fibromyalgia | 156 | RPT | 9.80 | 11.54 | 48 | 96 | Ο | G | NI | |
Substance Use | 133 | TAU | 10.29 | 0.00 | 34 | 46 | Inp | G | 1 | |
CP | 73 | TAU | 18.92 | 2.78 | 58 | 68 | O | G | 5 | |
TBI | 145 | PE | 12.00 | 19.15 | 34 | 22 | S | S | 4 | |
Physical Activity | 76 | PWP | 0.00 | 5.40 | 44 | 83 | S | S | 12 | |
HIV | 34 | TAU | 11.77 | 5.88 | 34 | 21 | O | Ind | 3 | |
BPD | 41 | TAU | 23.81 | 30.00 | 35 | 93 | O | G | 12 | |
Breast Cancer | 47 | Education | 21.74 | 12.50 | 56 | 100 | O | Ι | 6 | |
Chronic headache | 30 | MTAU | 26.67 | 0.00 | 36 | 100 | O | G | 8 | |
Multiple sclerosis | 21 | RT | 9.09 | 0.00 | 46 | 76 | O | G | 15 | |
Obesity | 73 | TAU | 8.33 | 10.81 | 42 | 100 | O | G | ||
Eating Disorders | 43 | TAU | 25.00 | 15.80 | 26 | 98 | O | Ind | 19 | |
Comorbid depression and alcohol use | 24 | TAU | 20.00 | 7.69 | 38 | 50 | Inp | Ind | M = 3.2 | |
CP | 63 | SPM | 25.81 | 21.88 | 46 | 64 | S | Ind | 12 | |
Psychosis | 44 | Befriending | 4.76 | 9.09 | 39 | 44 | O | Ind | 15 | |
Psychosis | 96 | Befriending | 6.12 | 8.51 | 36 | 39 | O | Ind | 8 | |
Diabetes | 106 | Education | 5.66 | 0.00 | 55 | 60 | O | G | 10 | |
Fibromyalgia | 67 | TAU | 9.09 | 0.00 | 40 | 95 | S | S | 8 | |
MUD | 104 | CBT | 56.86 | 56.60 | 31 | 40 | O | Ind | 12 | |
Fibromyalgia | 28 | Education | 0.00 | 0.00 | 49 | 100 | O | Ind | 8 | |
Methadone |
56 | TAU | 40.00 | 53.85 | 40 | 37 | O | Ind | 24 | |
CP | 90 | AR | 36.54 | 18.42 | 46 | 64 | S | S | 7 | |
CP | 238 | EW | 28.05 | 36.71 | 53 | 76 | S | S | 12 | |
OCD | 79 | PRT | 9.80 | 13.20 | 37 | 61 | O | Ind | 8 | |
Psychosis | 21 | TAU | 4.55 | 0.00 | 41 | 38 | I | Ind | 1 | |
OCD | 27 | SSRIs | 10.00 | 27.27 | 27 | 44 | O | G | NI | |
Procrastination | 79 | CBT | 11.54 | 7.69 | 21 | 47 | Ο | G | 8 | |
BS | 39 | TAU | 21.05 | 10.00 | 43 | 90 | S | S | 6 | |
Tinnitus | 64 | TRT | 0.00 | 10.00 | 51 | 47 | O | Ind | 10 | |
Anxiety | 21 | CBT | 0.00 | 44.44 | 71 | 48 | O | Ind | 12 | |
CP | 114 | CBT | 10.53 | 14.03 | 55 | 51 | O | G | 8 | |
Psychosis | 27 | TAU | 0.00 | 23.08 | 34 | 22 | O | Ind | 10 | |
LPP | 32 | MDT | 0.00 | 0.00 | 15 | 78 | O | Ind | 12 | |
Anxiety | 121 | CBT | 36.36 | 25.76 | 38 | 57 | O | Ind | 12 | |
Mathematics Anxiety | 24 | SD | 14.29 | 36.84 | 31 | 83 | O | Ind | 6 |
Regarding reasons reported for dropout, the majority of studies did not report data about client variables separately for dropout and completers. Of the 65 studies presenting dropouts in the ACT condition, only 27 studies (41.54%) reported reasons for dropout. Regarding comparisons, all participants completed treatment in 11 studies, whereas for the remaining 65 studies with dropouts, only 30 (45.15%) reported dropout reasons. For ACT, the most frequently reported reasons for dropout were: lost contact (
Across all studies and comparison conditions, the overall weighted mean dropout rate was 17.95%, 95% CI [15.12, 20.77]. ACT trials reported an average dropout rate of 17.35%, 95% CI [14.33, 20.37] and comparison conditions reported an average dropout rate of 18.62%, 95% CI [15.29, 21.96]. In the CMA, the unconstrained model with the 76 studies of ACT vs. comparison conditions, showed that the heterogeneity detected using the fixed-effects model was very small and non-significant, with Q(75) = 79.371,
Eight participant variables were first examined as moderators of therapy dropout (see
Moderator |
|
Mean Dropout Rate |
95% CI |
|
|
Q |
|
||
---|---|---|---|---|---|---|---|---|---|
ACT | Control | ACT | Control | ||||||
Client disorder | 7.101 | 0.526 | |||||||
Anxiety disorder or social phobia | 14 | 19.41 | 27.27 | 13.03, 25.79 | 21.05, 33.49 | -0.663 | 0.507 | ||
Depression | 2 | 16.82 | 19.47 | 10.57, 23.06 | -3.62, 42.56 | -0.567 | 0.571 | ||
Substance abuse or dependence | 6 | 28.73 | 24.91 | 11.08, 46.38 | 4.72, 45.09 | 0.122 | 0.903 | ||
Other health related problems | 10 | 12.80 | 12.90 | 5.88, 20.01 | 7.16, 18.64 | 0.064 | 0.949 | ||
Chronic Pain | 14 | 18.23 | 11.93 | 10.89, 25.66 | 5.61, 18.24 | 0.738 | 0.461 | ||
Chronic health conditions | 7 | 13.86 | 12.23 | 6.92, 20.81 | 6.33, 18.13 | 0.215 | 0.829 | ||
Eating pathology/disorder | 8 | 12.59 | 9.83 | 6.86, 18.32 | 4.88, 14.79 | 0.379 | 0.705 | ||
Smoking | 5 | 31.10 | 32.23 | 16.65, 45.55 | 16.81, 47.65 | -1.265 | 0.206 | ||
Severe psychopathology | 10 | 10.38 | 22.37 | 5.84, 14.92 | 12.28, 32.47 | -2.473 | 0.013 | ||
Population | 0.029 | 0.866 | |||||||
Children and adolescents | 3 | 11.41 | 13.59 | -0.45, 23.26 | -4.54, 31.72 | 0.759 | 0.448 | ||
Adults | 73 | 17.59 | 18.83 | 14.49, 20.70 | 15.42, 22.24 | -1.149 | 0.251 | ||
Country | 1.470 | 0.689 | |||||||
United States | 32 | 19.75 | 23.06 | 15.02, 24.49 | 17.20, 28.93 | -1.538 | 0.124 | ||
Australia | 8 | 17.22 | 21.68 | 4.82, 29.62 | 9.60, 33.76 | -0.441 | 0.659 | ||
Europe | 29 | 16.28 | 14.88 | 11.70, 20.86 | 10.90, 18.86 | 0.493 | 0.622 | ||
Asia | 7 | 10.96 | 10.33 | 3.91, 18.01 | 2.98, 17.68 | 0.221 | 0.825 | ||
Therapist experience level in ACT groups | 5.611 | 0.468 | |||||||
Masters/ master level therapists or doctoral students, interns, residents | 13 | 23.26 | 24.20 | 14.56, 31.96 | 15.53, 32.87 | 0.747 | 0.455 | ||
PhD therapists, doctorate | 15 | 15.24 | 14.25 | 8.69, 21.80 | 9.01, 19.50 | 0.006 | 0.995 | ||
Mix PhD, students and others | 15 | 16.34 | 21.90 | 10.17, 22.52 | 13.32, 30.48 | -2.366 | 0.018 | ||
Not informed | 5 | 10.90 | 11.57 | 3.08, 18.73 | 0.20, 22.94 | -0.738 | 0.461 | ||
Psychologists mixed levels | 19 | 16.15 | 18.35 | 10.34, 21.95 | 11.43, 25.26 | -0.080 | 0.936 | ||
No therapists (online) | 8 | 19.92 | 17.43 | 8.87, 31.16 | 6.10, 28.75 | 0.059 | 0.953 | ||
Non-psychologists | 1 | 21.74 | 12.50 | - | - | 0.833 | 0.405 | ||
Therapist experience level in comparison groups | 5.990 | 0.541 | |||||||
Masters/ master level therapists or doctoral students, interns, residents | 10 | 24.37 | 23.10 | 14.65, 34.09 | 13.38, 32.82 | 0.765 | 0.444 | ||
Mix PhD, students and others | 15 | 14.99 | 20.58 | 9.82, 20.15 | 14.21, 26.95 | -1.479 | 0.139 | ||
Psychiatrists | 2 | 34.74 | 42.46 | 31.49, 37.99 | 33.91, 51.01 | -2.087 | 0.037 | ||
PhD therapists, doctorate | 9 | 17.85 | 17.84 | 7.37, 28.34 | 10.28, 25.41 | 1.221 | 0.222 | ||
Non-psychologists (drug staff, alcohol counselor, physician, psycho-pharmacologist) | 9 | 13.49 | 18.06 | 8.05, 18.94 | 7.18, 28.94 | -0.122 | 0.903 | ||
Not informed | 12 | 14.49 | 9.45 | 9.37, 19.61 | 3.05, 15.85 | -0.579 | 0.563 | ||
Psychologists mixed levels | 13 | 15.03 | 17.29 | 6.41, 23.66 | 8.05, 26.52 | 0.060 | 0.953 | ||
No therapists (online) | 6 | 21.53 | 21.57 | 6.74, 36.33 | 8.14, 35.00 | -0.284 | 0.777 | ||
Definition of dropout | 0.166 | 0.999 | |||||||
failed to complete treatment/ discontinue treatment/leave before the end of tx/refused to return in tx | 53 | 15.35 | 18.40 | 11.65, 19.06 | 14.36, 22.43 | -0.234 | 0.815 | ||
attended less than or equal to 50-75% of total sessions/weeks | 11 | 22.82 | 18.68 | 15.69, 29.94 | 9.51, 27.86 | -1.267 | 0.205 | ||
attended less than or equal to 76-90% of total sessions | 6 | 24.63 | 20.47 | 14.94, 34.31 | 5.70, 35.23 | -0.358 | 0.720 | ||
failed to attend all sessions | 2 | 20.54 | 21.45 | -5.37, 46.44 | 4.69, 38.21 | -0.131 | 0.896 | ||
attended less than or equal to 25-40% of total sessions or groups | 2 | 21.60 | 22.41 | 8.96, 34.24 | -5.62, 50.44 | -0.317 | 0.751 | ||
failed to submit pre and post-treatment data | 2 | 10.96 | 12.15 | 1.48, 20.43 | 5.02, 19.28 | -0.279 | 0.781 | ||
Study type | 0.366 | 0.545 | |||||||
Efficacy | 42 | 17.37 | 20.37 | 13.06, 21.67 | 15.71, 25.03 | -1.248 | 0.212 | ||
Effectiveness | 34 | 17.33 | 16.46 | 13.10, 21.56 | 11.74, 21.18 | -0.064 | 0.949 |
*
Regarding categorical moderators, there were no significant differences between subgroups. This was expected as heterogeneity among the studies was very small and the studies were generally favoring ACT groups but this finding did not reach statistical significance. However, separate investigation of the effect sizes in each subgroup of studies showed that a significant finding was noted in the subgroup analysis for the type of disorder under investigation (see Appendix C in
Eight treatment variables were tested as moderators of dropout rate (see
Moderator |
|
Mean Dropout Rate |
95% CI |
|
|
Q |
|
||
---|---|---|---|---|---|---|---|---|---|
ACT | Control | ACT | Control | ||||||
Treatment format in ACT groups | 0.131 | 0.988 | |||||||
Group | 34 | 15.92 | 15.26 | 12.32, 19.52 | 11.06, 19.47 | -0.154 | 0.878 | ||
Individual | 30 | 16.37 | 20.96 | 11.09, 21.66 | 15.12, 26.80 | -0.518 | 0.605 | ||
Combined | 3 | 38.24 | 36.31 | 31.13, 45.35 | 23.28, 49.34 | -1.112 | 0.266 | ||
Self-help | 9 | 19.04 | 17.62 | 8.97, 29.10 | 7.62, 27.61 | -0.521 | 0.602 | ||
Description of recruitment setting | 9.254 | 0.235 | |||||||
Outpatient clinic affiliated with hospital or med-school | 11 | 16.88 | 18.72 | 6.28, 27.48 | 7.46, 29.98 | 0.738 | 0.461 | ||
Private outpatient clinic/practice | 2 | 12.05 | 28.03 | 7.64, 16.45 | -1.04, 57.10 | -1.351 | 0.177 | ||
Public outpatient clinic and community advertisements | 21 | 14.44 | 21.30 | 9.39, 19.49 | 14.84, 27.76 | -2.985 | 0.003 | ||
Research or specialty clinic | 6 | 17.49 | 17.91 | 6.94, 28.03 | 11.57, 24.25 | 0.989 | 0.323 | ||
University affiliated clinic (psychology training clinic and university counseling center) | 10 | 26.04 | 24.41 | 19.01, 33.07 | 13.98, 34.84 | -0.449 | 0.653 | ||
Inpatient or residential treatment | 6 | 9.21 | 3.43 | 3.27, 15.14 | 0.28, 6.57 | 0.442 | 0.659 | ||
At home (self-help and web-based treatments) | 11 | 19.90 | 17.54 | 11.66, 28.14 | 9.36, 25.72 | -0.476 | 0.634 | ||
Not informed | 9 | 18.46 | 15.66 | 8.72, 28.21 | 8.76, 22.56 | 1.031 | 0.302 | ||
Treatment setting | 0.442 | 0.802 | |||||||
Outpatient | 60 | 17.77 | 20.24 | 14.34, 21.20 | 16.48, 24.00 | -1.063 | 0.288 | ||
Inpatient | 6 | 9.21 | 3.43 | 3.27, 15.14 | 0.28, 6.57 | 0.442 | 0.659 | ||
Self-Help (including web-based) | 10 | 19.71 | 18.05 | 10.61, 28.81 | 9.07, 27.02 | -0.405 | 0.686 | ||
Treatment status | 1.273 | 0.259 | |||||||
Providing treatment | 59 | 16.31 | 19.23 | 12.92, 31.95 | 15.50, 22.95 | -1.139 | 0.255 | ||
Non-providing treatment | 17 | 20.94 | 16.53 | 14.50, 27.39 | 8.93, 24.13 | -0.035 | 0.972 | ||
Comparison group | 2.845 | 0.724 | |||||||
CBT | 17 | 18.73 | 24.25 | 11.18, 26.27 | 16.89, 31.61 | -0.188 | 0.851 | ||
TAU | 17 | 14.30 | 13.60 | 10.57, 18.04 | 7.42, 19.79 | 0.413 | 0.680 | ||
Medication only | 9 | 22.63 | 23.61 | 13.08, 32.18 | 12.30, 34.92 | -1.037 | 0.300 | ||
Other active treatment | 12 | 20.58 | 21.42 | 12.07, 29.09 | 11.93, 30.92 | -1.452 | 0.147 | ||
Component of CBT | 12 | 17.07 | 19.36 | 10.03, 24.10 | 12.83, 25.89 | -0.596 | 0.551 | ||
Education only | 9 | 11.30 | 7.77 | 1.78, 20.82 | 1.77, 13.77 | 1.233 | 0.218 |
*
Only a small amount of studies reported therapist gender, age, and ethnicity, deeming it impossible to analyze them as moderators. The experience levels of the therapists in ACT and comparison groups showed non-significant differences. However, in the subgroup analysis of the ACT therapists’ experience level a significant effect size was found for the subgroup of therapists from mixed experience levels, including doctoral level, student trainees, and others (e.g., licensed clinicians, psychiatrists, social workers, psychiatric nurses). The odds on dropout from ACT groups were significantly lower than from comparison groups when the ACT therapists consisted of a multi-level and multi-domain team, with
We performed sensitivity analyses based on decisions taken before, or based on the previous findings of the meta-analysis. The exclusion of the three studies that consisted of dissertations, showed that the main effect did not change significantly, with
Treatment dropout is an important parameter impacting treatment outcomes (
As noted by others, we found that there is no consensus regarding the definition employed by investigators. We adopted a broad definition of treatment dropout, utilizing what was reported by each study author and particularly considering dropouts to be the percentage of cases of individuals who began treatment but did not complete it as intended by its developer. Based on this definition, the yielded overall dropout rate across all studies included in this meta-analysis was 17.95%, which is comparable to recent previously meta-analytically reported rates (i.e., 19.70%;
Unfortunately, the majority of examined studies did not include dropout reasons, limiting our ability to draw conclusions regarding the reasons for dropout. Despite the limited number of studies presenting reasons for dropouts, some important differences between ACT and other groups were identified. For example, most individuals who dropped out from ACT groups did so because of lost contact and for (unrelated to therapy) personal reasons. Dropout reasons in comparison conditions however, included additionally therapy-related reasons (e.g., not satisfied with the treatment or feeling that the therapy was too time consuming). In particular, when ACT was compared to CBT, the most frequent reason for dropping out of CBT was therapy factors (i.e., of the 5 studies who reported reasons for dropout from CBT, all of them mentioned therapy factors). In contrast, in ACT, the reasons of time demands, transportation, personal and therapy were equally reported. This is in line with findings reported by
In this review, we found that ACTs’ premature termination rates were lower for dealing with certain types of psychopathology (severe psychopathology). This finding may highlight the important addition of ACT skills for severe psychopathologic conditions; however this needs to be further explored. Interestingly, participants’ age did not moderate dropout rates, suggesting that all age groups result in similar dropout rates. This is a divergence from the
The subgroup analyses based on the description of the treatment setting showed that dropout rates from ACT groups were lower for studies in which the treatment was delivered in a public outpatient clinic and population was recruited by community advertisements. However, one should note that these studies were highly heterogeneous, including participants with anxiety disorders, eating disorders, substance abuse, other health problems, chronic pain, health conditions/chronic illnesses, smoking, severe psychopathology (i.e., BPD, psychosis, treatment resistant), and depression. Additionally, in most of these studies the comparison condition was not another psychologically active intervention (i.e., in 57% of them the comparison group was treatment as usual, medication only and education). Due to the high heterogeneity of these studies, this finding should be interpreted with caution and further examined in the future.
In terms of provider moderators, experience level of providers in ACT and comparison groups were significantly related to dropout rates. Specifically, when treatment was delivered by a multi-level and multi-domain team, ACT had lower dropout rates than comparison conditions. This is a divergence from the studies of
This study has several limitations that need to be considered in the interpretation of findings. First, the inclusion criteria were made broad enough in order to include a large number of studies. All age groups were included; as well as various psychopathological and non-psychopathological problems, and studies combining ACT with other interventions or medication. Though we attempted to deal with this heterogeneity in the disorders, interventions, populations and age conditions by examining moderators of interest, this heterogeneity may have still affected the clarity of any differences between ACT and comparison groups on dropout rates.
A second limitation may be related to the coding procedure. Specifically, for the variable of comparison condition, when a study had two comparison conditions we selected to compare only the active treatment (e.g., CBT) and excluded the inactive comparison condition (e.g., wait-list). A third limitation has to do with reasons reported for dropouts. Specifically, the majority of studies did not report dropout reasons, making conclusions about true reasons for dropout impossible or biased for the studies that reported these reasons. In order to further elucidate the phenomenon of treatment dropout, future studies should examine and report reasons why participants drop out as well as the timing when this occurs. Finally, in our meta-analysis it was not possible to carry out a comparison between the demographic characteristics of dropouts and completers due to insufficient data provided by studies. We would like to encourage researchers to ensure that they report information separately for completers and dropouts so as to facilitate further understanding into the phenomenon of dropout.
This review examined dropout rates of a third wave CBT intervention in a range of disorders, populations, ages and comparison conditions. Our findings show that overall dropout rates between ACT and comparison conditions were not found to differ significantly. Additionally, moderation analyses suggest that experience level of therapists in ACT and comparison conditions, description of treatment setting, and client diagnosis are associated with an increased likelihood of dropout. Therefore, interventions aiming to lower attrition should plan a-priori how to better engage users belonging to these groups.
Our findings suggest that ACT may present some potential advances for improving client engagement and retention, such as emphasizing that any behavior change needs to be linked with the persons’ values, or it may include more interesting treatment content through the use of metaphors and experiential exercises. However, more research is still needed prior to being able to assertively make these conclusions.
The findings of the present study offer possible hypotheses about which therapeutic processes are associated with client retention. However, more studies are needed that will examine particular reasons for premature treatment termination, timing when this phenomenon occurs and how it may be linked to specific treatment components, and associated variables in third wave treatments.
Moderators of the dropout effect for different therapeutic approaches are critical in that they illuminate areas that may still have potential for improvement in the context of an otherwise effective intervention. This needs to be further examined. For example, even if ACT has lower dropout rates than some comparison conditions overall, but females drop out more from ACT than comparison conditions, then ACT may need to consider how females are being engaged in the intervention and attempt to find ways to improve engagement (e.g., maybe more gender sensitive metaphors). Additionally, common vs. specific factors in the psychotherapies being examined and in relation to how these may affect dropout also need to be examined. Researchers are encouraged to examine and report the reasons for dropout when a person discontinues the treatment prematurely. Further understanding of these reasons should allow us to examine whether it is dissatisfaction with the common factors (e.g., therapeutic alliance, expectations, cultural adaptations, empathy) that contribute to premature discontinuation or whether dropout is related to specific factors (e.g., specific ingredients of the intervention provided). It is essential that participant engagement and premature termination continue to serve as topics of exploration in the clinical psychology arena, so as to improve the effectiveness of interventions, decrease treatment dropout rates, and enhance the possible treatment effects for participants.
Datasets for the studies are freely available (see the
The following data and materials are available for this study (for access see Index of
Appendix A: Percentages of clients reporting each of the reasons for the included studies
Appendix B: Forest and funnel plots of included studies
Appendix C: Forest plot of subgroup analyses based on the type of disorder under investigation
Appendix D: Sensitivity analysis for the year of publication
Appendix E: Checklist of definitions and variables to be collected in order to properly document dropouts
Preregistered protocol (CRD42017068456) of the current study
The authors received no financial support for the research, authorship, and/or publication of this article.
The authors declare no conflicts of interest.
The authors have no support to report.