A Systematic Review & Meta-Analysis of Cognitive Behavioral Therapy (CBT) Intervention for Adults with Attention-Deficit Hyperactivity Disorder (ADHD)

Taran S. DePaola & Victoria L. WarnockDepartment of Psychological Sciences, Northern Arizona University, Flagstaff, Arizona

IntroductionAttention-Deficit Hyperactivity Disorder (ADHD) is characterized by the inability to focus,

problems with sustaining attention, increased likelihood of impulsivity, hindered motivation and memory, and other forms of impaired executive functioning (Mongia & Hechtman, 2012). Alongside those symptoms are usually comorbidities, ranging from depression to anxiety problems and even substance use disorders (Mongia & Hechtman, 2012; Simon, Czobor, Balint, Meszaros, & Bitter, 2009). ADHD can cause serious dysfunction in an individual’s life, usually resulting in mood disturbances and life dissatisfaction. Most often diagnosed in childhood, ADHD has been observed to remain persistent throughout adolescence and adulthood (Toplak, Connors, Shuster, Knezevic, & Parks, 2008; DSM-IV-TR, American Psychiatric Association, 2000). This review investigates the scope of Cognitive Behavioral Therapy (CBT) intervention for adults who suffer from ADHD, and the prevalence of the disorder has been debated. Researchers Simon et al., 2009, have suggested that in the general population there may exist a 1-7.3% rate of adults with ADHD when diagnosed using the DSM-IV. Many adults who have the disorder opt to try pharmacological treatment, as it has been shown to be very effective in managing the symptoms of ADHD (Vidal-Estrada, Bosch-Munso, Nogueira-Morais, Casas-Brugue, & Ramos-Quiroga, 2012). However, drug treatment alone is not always effective and is shown to be more efficacious when coupled with psychotherapy (Toplak et al., 2008; Mongia & Hechtman, 2012; Vidal-Estrada et al., 2012). CBT has been a very effective form of psychotherapy when treating ADHD, and it is characterized by educating the patient (individual with ADHD, in this case) about maladaptive behaviors commonly associated with ADHD and remedying those behaviors with healthy ones. CBT involves many cognitive and emotional facets; focusing on cognitive aspects of CBT would be anything related to an individuals’ daily functioning such as organization, time and money management, problem solving and rational thinking, and many other components of cognitive science; while the emotional aspect of CBT revolves around self-control and self-regulation procedures, among many others related to emotional modulation (Mongia & Hechtman, 2012; Toplak et al., 2008). Furthermore, CBT may be administered in small groups or individually and can consist of multiple sessions ranging from 6 to 14; CBT may also run the course of many weeks, sometimes for multiple months when the treatment is more rigorous (Toplak et al., 2008; Mongia & Hechtman, 2012). The purpose of the current project was to conduct a systematic review and meta-analysis of CBT treatment for adults diagnosed with ADHD with or without pharmacological intervention.

Methods The American Psychological Association Division 12 website, the Society of

Clinical Psychology, was accessed to find initial sources regarding adult ADHD, and of the four sources provided we utilized those reference sections to look for any review articles, randomized controlled trials, and meta-analyses. Almost every resource provided in the reference sections could be obtained using EBSCOhost search engines Medline and PsycINFO through the NAU Cline Library website. Furthermore, to locate more studies the above search engines were the ones chosen as well as Google Scholar. Eligibility screening criteria for the search process consisted of both male and female participants that are at least 18 years of age or older. The following search terms were used in the systematic literature review: Adult Attention-Deficit Hyperactivity Disorder; ADHD and Adults; CBT and ADHD; Cognitive Behavioral Therapy and ADHD; Cognitive Behavioral Therapy and Attention-Deficit Hyperactivity Disorder; CBT and Attention-Deficit Hyperactivity Disorder; CBT and ADHD and RCT; CBT and ADHD and Randomized-Controlled Trials; and First Authors Last Name/ CBT/ Cognitive/ Therapy/ RCT/ Randomized/ Controlled/ Trials / ADHD. Dates of coverage for peer-reviewed articles included in this study range from 2004 to present year. Overall, this review encompasses 6 RCTs and 1 meta-analysis.

ResultsThe outcomes of the psychotherapy studies utilized in this systematic review and meta-analysis held overwhelmingly positive results for the efficacy of CBT for adults with ADHD. Information obtained was from six RCTs, and one within subjects design. These studies suggest that CBT is efficacious regardless of the medium of experimentation presented; such as combination intervention (CBT & medication), internet-based CBT, individual in-person administered CBT intervention, or group administered CBT intervention. Most studies compared pre-treatment baseline indicators of ADHD symptom severity with post-treatment symptom severity and a follow-up period that assessed sustainability of psychotherapy efficacy intervention over time. The control groups used ranged from treatment as usual (TAU) involving medication only, TAU involving medication and another form of therapy, TAU with no medication but with therapy or placebo, and wait-list controls (WLC). The range of follow-up periods for the studies included was from three months to twelve months. Overall, these studies indicate that CBT intervention is successful for reducing the severity of ADHD symptoms in adults and improving quality of life, when compared to pharmacological intervention alone. Combination therapy was shown to be equally successful to CBT intervention alone, with a positive dose-response relationship wherein the greater the number of sessions of CBT the greater the efficacy. The mean omnibus effect size across the 12 outcome variables pulled from the six studies collected was 0.59.

AbstractThe purpose of our current project was to conduct a systematic review of the

efficacy of psychotherapeutic clinical trials of Cognitive Behavioral Therapy (CBT) for adult patients diagnosed with Attention-Deficit Hyperactivity Disorder (ADHD). Eligibility of participants screened for this systematic review consisted adults aged 18 years or older, and the studies analyzed include review articles, randomized controlled trials, and a meta-analysis. The literature search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards and regulations (PRISMA: Liberati et al., 2009). Results indicated that CBT is an efficacious therapy intervention for adults with ADHD. Strengths and limitations are evaluated and discussed, as well as suggestions for future research. Furthermore, a meta-analysis was also conducted to determine the effect size of select continuous variables between studies.

Author/Year/Design

N Control Group Measures Follow-up Main Outcomes Cohen’s d

Emilsson et al.(2011): RCT

54 TAU (meds only) K-SADS-PL; BCS-total

3 months Significant effect for improvement in core ADHD symptoms at post-treatment.The group receiving both CBT and medication reported a significant reduction in ADHD symptoms, more than the reduction reported from the TAU group.

d = .9

Safren et al. (2005): RCT

31 TAU (meds only) K-SADS-E; CSS; ADHD-RS-IV

N/A Those participants who received CBT and medications (combo) had significantly lower (IE) scores on the ADHD-RS-IV. At post-treatment, the group that received combo intervention had lower overall CSS scores than those in the TAU group.

d = .8

Safren et al. (2010): RCT

79 Relaxationwith education

K-SADS-E; CSS; ADHD-RS-IV

12 months Those who received CBT had fewer reported symptoms on the ADHD-RS-IV post-treatment than those in the control condition. The CBT condition group’s weekly CSS scores were significantly lower (better) than the control groups weekly CSS scores. 

d = .65

Solanto et al. (2010): RCT

88 Supportive Therapy AISRS-IS; AISRS-TMOPS

N/A There was a significant difference in pre/post scores on the AISRS-IS and AISRS-TMOPS in the CBT group when compared with the control group (greater change than in control condition). Those that were in the cognitive therapy group demonstrated greater improvement than the control group for inattention measures, time management, organization, and planning.

d = .62

Pettersson et al. (2014): RCT

45 WLC AIM-A LwA; CSS 6 months The iCBT-G group, when compared to the WLC group, showed significant reduction in ADHD symptoms congruent with the CSS while the WLC group did not. Regarding the AIM-A LwA there were no reported significant differences between the two groups.

d = .23

Weiss et al. (2012): RCT

23 CBT & Placebo ADHD RS-Inv; SDS

N/A There were no significant differences between the CBT and medication group vs. the control group. However, both groups showed improvements over time on both the ADHD RS-Inv and the SDS.

d = .34

Rostain & Ramsay(2006): WS

43 N/A BADDS; CGI-A N/A The BADDS total showed significant improvement of reported symptoms of ADHD. No participants were rated as doing worse in functionality or severity of symptoms post treatment for the CGI-A.

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N= sample size; CBT= Cognitive Behavioral Therapy; ADHD= Attention-Deficit Hyperactivity Disorder; RCT= randomized-controlled trial; WS= within subjects design; N/A= not applicable; TAU= treatment as usual; WLC= wait-list control; K-SADS-PL= Kiddie-Schedule for Affective Disorders and Schizophrenia (present and lifetime versions); K-SADS-E= Kiddie-Schedule for Affective Disorders and Schizophrenia (epidemiological); BCS= Barkley Current Symptoms Scale; CSS= Current Symptom Scale; ADHD-RS-IV= Attention-Deficit Hyperactivity Disorder Rating Scale-IV; AISRS-IS= Adult ADHD Investigator Symptom Rating Scale (inattention subscale); AISRS-TMOPS= Adult ADHD Investigator Symptom Rating Scale (time management, organization, and planning subscale); AIM-A LwA= ADHD Impact Module-Adult, Multi-Item Scale Living With ADHD; ADHD RS-Inv= Attention-Deficit Hyperactivity Disorder Rating Scale Inventory; SDS= Sheehan Disability Scale; BADDS= Brown’s Attention Deficit Disorder Scale; CGI-A= Clinical Global Impression of ADHD.

Table 1. Summary of Clinical Trials of CBT & Medication Combination for Adult ADHD.

DiscussionConclusions: CBT demonstrates efficacy in adults suffering from ADHD regardless of whether

or not utilizing combination therapy, which involves the addition of pharmacological intervention. Furthermore, CBT is effective in treating symptom severity of ADHD in adults through internet-based CBT sessions as well. The compiled literature for this systematic review reported empirical evidence in support of CBT as treatment for ADHD. Overall, CBT tends to improve the quality of life for adults who suffer from ADHD. The results of the meta-analysis we calculated was a Cohen’s d value of .059, which indicates a medium effect size (Cohen, 1997).

Strengths: The utilized RCTs demonstrated robust internal validity, with strong research designs that included numerous empirically established psychometric instruments to assess the severity of ADHD symptoms in adults. All of the included RCTs alternated between multiple measures of the primary outcomes of interest. Almost all of the RCTs included both a series of independently evaluated questionnaires and clinical interviews for the assessment of symptom severity in participants. The majority of the obtained studies also utilized a follow-up period.

Limitations: The major limitations that occurred across the included studies emphasized a lack of consistency in sample sizes and design parameters of the study. For instance, some RCTs looked at CBT efficacy in adults previously prescribed medication for ADHD, or used pharmacological intervention in addition to CBT while other studies assessed if CBT was more effective than other forms of psychotherapy. In general, the obtained RCT sample sizes ranged dramatically, exclusion criteria varied from one study to the next, and each RCT experienced participants who failed to complete the treatment intervention. Only one RCT study utilized multiple time points to assess for symptom severity reduction in adults with ADHD.

Recommendations for Future Research: The majority of published studies that examine the efficacy of CBT for adults suffering from ADHD have been small-scale experimental studies with relatively limited sample sizes and issues with participant drop-out rates and a lack of medication consistency. Based on the overall positive results of CBT with adults suffering from ADHD, future research should concentrate on replicating large-scale studies with an emphasis on replicating the preliminary findings from previous results. In addition, future research on CBT with adults suffering from ADHD should take measures to control for medication changes throughout the clinical trial to rule out potential interference from extraneous variables and focus on reducing the factors that may contribute to participant dropout rates that alter the data obtained during clinical trials.

Methods ContinuedWe conducted a meta-analysis using continuous variables from trials where

means, standard deviations, and sample sizes for treatment and control groups were included. The two most important outcome variables from studies where this data was available were included. The meta-analysis was conducted using (http://www.campbellcollaboration.org/). The overall effect size across studies was calculated by computing the arithmetic mean of effect sizes from each study included in the analysis. Absolute values of negative effect sizes were used for the analysis.