STIM-ADHD: A parallel randomized double-blind sham-controlled multicenter trial of transcranial direct current stimulation (tDCS) in adult attention deficit hyperactivity disorder.

• Applicant: Professorin Dr. Maria Strauß
• Subject Area: Biological Psychiatry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452675967

Adult attention deficit/ hyperactive disorder (ADHD) is a common and under-recognized disorder with a childhood-onset characterized by attention deficit, impulsivity and hyperactivity/restlessness. Its symptoms have detrimental impacts on social, financial, professional functioning and require lifelong treatment. Frequent comorbidities negatively affect the already increased mortality. Gold standard is pharmacotherapy, but multimodal treatment is needed because of 30% non-responders, common side effects and concerns of abuse. Many patients continue to have cognitive failures despite medication impacting quality of life. Therefore, additional treatment options are needed. Transcranial direct current stimulation (tDCS) is a non-invasive safe method with potential benefits for ADHD patients. Evidence shows that ADHD patients have altered levels of excitability in specific brain areas, which can be modulated by tDCS, improving cognitive functions. Confirmatory trials with sufficient sample sizes are missing. Our aim is to evaluate short- and mid-term effects of tDCS in a multicenter, randomized, double-blind, sham-controlled, parallel group, clinical trial with a 1:1 randomization ratio. Primary endpoint is the total score of DSM IV-scale of the internationally established Conners’ Adult ADHD Rating Scales (CAARS-SB), at day 14 post-intervention (p.i.) to detect short-term lasting effects analyzed via ANCOVAs. In case of significant between-group differences at day 14 p.i., hierarchically ordered hypotheses on mid-term lasting effects by linear mixed models with visit (5 time points), treatment, treatment by visit interaction, covariates as fixed categorical effects plus a patient-specific visit random effect, using an unstructured covariance structure to model the residual within-patient errors. Secondary endpoints are the DSM IV-subscales Inattention, Hyperactivity/Impulsivity of CAARS-S SB, results of metric Continuous Performance Test, scores/scales of quality of life (AAQOL-29), sleep (PSQI) and complaints (SCL-90-R) analyzed by ANCOVA/LMM analogously to the primary analyses.

• DFG Programme: Clinical Trials
• Co-Investigator: Dr. Christine Ulke