Transcranial Direct Current Stimulation vs Sham for the Treatment of Inattention in Adults With Attention-Deficit/Hyperactivity Disorder

Abstract

IMPORTANCETranscranial direct current stimulation (tDCS) may improve symptoms of inattention in adults with attention-deficit/hyperactivity disorder (ADHD). However, previous trials are characterized by small sample sizes, heterogeneous methodologies, and short treatment periods using clinic-based tDCS. OBJECTIVE To determine the efficacy and safety of home-based tDCS in treating inattention symptoms in adult patients with ADHD. DESIGN, SETTING, AND PARTICIPANTS Randomized, double-blind, parallel, sham-controlled clinical trial (tDCS for the Treatment of Inattention Symptoms in Adult Patients With ADHD [TUNED]), conducted from July 2019 through July 2021 in a single-center outpatient academic setting. Of 277 potential participants screened by phone, 150 were assessed for eligibility on site, and 64 were included. Participants were adults with ADHD, inattentive or combined subtype. Exclusion criteria included current stimulant drug treatment, current moderate to severe symptoms of depression or anxiety, diagnosis of bipolar disorder with a manic or depressive episode in the last year, diagnosis of schizophrenia or another psychotic disorder, and diagnosis of autism spectrum disorder; 55 of participants completed follow-up after 4 weeks. INTERVENTIONS Thirty-minute daily sessions of home-based tDCS for 4 weeks, 2 mA anodal-right and cathodal-left prefrontal stimulation with 35-cm 2 carbon electrodes. MAIN OUTCOMES AND MEASURES Inattentive scores in the clinician-administered version of the Adult ADHD Self-report Scale version 1.1 (CASRS-I).RESULTS Included in this trial were 64 participants with ADHD (31 [48%] inattentive presentation and 33 [52%] combined presentation), with a mean (SD) age of 38.3 (9.6) years. Thirty participants (47%) were women and 34 (53%) were men. Fifty-five finished the trial. At week 4, the mean (SD) inattention score, as measured with CASRS-I, was 18.88 (5.79) in the active tDCS group and 23.63 (3.97) in the sham tDCS group. Linear mixed-effects models revealed a statistically significant treatment by time interaction for CASRS-I (β interaction = −3.18; 95% CI, −4.60 to −1.75; P < .001), showing decreased symptoms of inattention in the active tDCS group over the 3 assessments compared to the sham tDCS group. Mild adverse events were more frequent in the active tDCS group, particularly skin redness, headache, and scalp burn. CONCLUSIONS AND RELEVANCEIn this randomized clinical trial, daily treatment with a home-based tDCS device over 4 weeks improved attention in adult patients with ADHD who were not taking stimulant medication. Home-based tDCS could be a nonpharmacological alternative for patients with ADHD.

A randomized, sham-controlled trial of high-definition transcranial direct current stimulation on the right orbital frontal cortex in children and adolescents with attention-deficit hyperactivity disorder

“…The likely explanation was that most of the previous studies tested five sessions and only two studies tested larger numbers of sessions. Westwood et al ( 59 ) found no improvement after 15 sessions and Leffa et al ( 17 ) found an improvement after 28 sessions but not after 14 sessions. This suggested that we need more sessions.…”

“…According to recent research, Leffa et al performed daily sessions of 30 min of home-based tDCS for 4 weeks on 64 participants with ADHD, totaling 28 sessions, with 2.0 mA anodal-right and cathodal-left prefrontal stimulations with 35-cm 2 carbon electrodes. The efficacy results assessed by the inattentive scores of the clinician-administered versions of the Adult ADHD Self-report Scale (CASRS-I) show decreased symptoms of inattention in the active tDCS group over the three assessments compared to the sham tDCS group ( 17 ). However, according to several research studies, there is no evidence that tDCS can improve the response inhibition ability ( 18 ) and the sustained attention ( 19 ) of patients with ADHD.…”

Remote neurocognitive interventions for attention-deficit/hyperactivity disorder – opportunities and challenges

“…tingling). These results suggest that tDCS is a promising remote treatment option for AD/HD, and further studies are needed to optimize tDCS parameters for eliciting larger effects (Cosmo et al, 2020;Leffa et al, 2022).…”

“…One recent study extended the use of tDCS to a home setting in adults with AD/HD (Leffa et al, 2022). To our knowledge, this is the first home-based tDCS RCT for AD/HD.…”

The Impact of Bilateral Anodal tDCS over Left and Right DLPFC on Executive Functions in Children with ADHD

“…The only tDCS study that specifically investigated the role of the right DLPFC found a partial improving effect of right DLPFC anodal tDCS (single session) in response inhibition that was dependent on symptom severity [ 27 ]. Another recently published work in adult ADHD showed improving effects of multisession anodal right cathodal left prefrontal tDCS on attentional deficits [ 28 ]. Yet with the current literature, the comparative contributions of the left and right DLPFCs in ADHD are not well-known.…”