Recognition and Treatment of Attention Deficit-Hyperactivity Disorder in Patients with Treatment-Resistant Burning Mouth Syndrome: A Retrospective Case Study

Kaori Takahashi ¹ Satoshi Kasahara ^2* Miwako Takahashi ³ Taito Morita ² Naoko Sato ⁴ Toshimitsu Momose ⁵ Ko Matsudaira ⁶ Shin-Ichi Niwa ⁷ Kanji Uchida ² Toshiyuki Handa ¹ Tatsuya Ichinohe ¹ Ken-Ichi Fukuda ⁸

• ¹ Department of Dental Anesthesiology, Tokyo Dental College, Tokyo, Japan
• ² Department of Anesthesiology and Pain Relief Center, the University of Tokyo Hospital, Tokyo, Japan
• ³ Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan
• ⁴ Nursing Department, the University of Tokyo Hospital, Tokyo, Japan
• ⁵ Institute of Engineering Innovation, School of Engineering, the University of Tokyo, Tokyo, Japan
• ⁶ Department of Pain Medicine, Fukushima Medical University School of Medicine, Fukushima, Fukushima, Japan
• ⁷ Department of Psychiatry, Aizu Medical Center, Fukushima Medical University, Fukushima, Fukushima, Japan
• ⁸ Division of Special Needs Dentistry and Orofacial Pain, Tokyo Dental College, Tokyo, Japan

Introduction: Burning mouth syndrome (BMS) is an idiopathic oral pain disorder characterized by burning sensations and dysesthesia, often complicated by psychosocial factors and psychiatric comorbidities, necessitating a multidisciplinary approach. BMS, classified as nociplastic pain (NcplP), frequently involves central sensitization. Attention-deficit/hyperactivity disorder (ADHD), a neurodevelopmental disorder, is commonly comorbid with NcplP, and ADHD-targeted treatment has shown efficacy in NcplP management. However, the role of ADHD diagnosis and treatment on BMS and associated brain function abnormalities remains unexplored. Therefore, we aimed to investigate the prevalence of ADHD comorbidity and its assessment using ADHD scales and the therapeutic efficacy of an ADHD-focused algorithm, including pre-and post-treatment cerebral blood flow single-photon emission computed tomography (SPECT) results, in patients with treatment-resistant BMS referred from the outpatient clinic of dental psychosomatic specialists at a tertiary care institution for multidisciplinary treatment. Methods: We retrospectively analyzed data from 14 patients with treatment-resistant BMS who received multidisciplinary care, including psychiatric evaluation and SPECT imaging. Clinical assessments included the Conners' Adult ADHD Rating Scale (CAARS-S and CAARS-O), Pain Numerical Rating Scale, Hospital Anxiety and Depression Scale, and Pain Catastrophizing Scale. Algorithm-based pharmacotherapy using ADHD-effective medications (methylphenidate, atomoxetine, guanfacine, aripiprazole, venlafaxine, and duloxetine) was administered. Results: ADHD was diagnosed in 13 patients (92.9%), with 57.2% exhibiting borderline or clinical-level symptoms. Clinically significant improvements were observed in all clinical scales among the 10 patients who completed algorithm-based treatment. Brain perfusion SPECT identified hypoperfusion in the frontal lobe and hyperperfusion in the perigenual anterior cingulate cortex, insular cortex, posterior cingulate gyrus, and precuneus in 90% of cases, with improvements noted following treatment. Conclusions: ADHD is frequently comorbid in patients with treatment-resistant BMS, and ADHD-targeted pharmacotherapy may help alleviate pain, cognitive dysfunction, and brain perfusion abnormalities. These findings suggest that ADHD screening, diagnosis, and multidisciplinary management involving psychiatrists could play a crucial role in optimizing clinical outcomes in patients with BMS.