JPRN‐JMA‐IIA00438.

Methods	8‐week parallel trial of pyridoxamine versus placebo
Participants	Inclusion criteria: boys and girls at least 12 years old parent, legal guardian or individual provide consent to participate minimum score of 18 on the Japanese version of the ABC (ABC‐J) Exclusion criteria known sensitivity to vitamin B6 diagnosed with schizophrenia, biploar, major depressive disorder, or undergoing oral treatment for a mental disorder severe liver or heart disease, or impaired renal function; any gastrointestinal, respiratory, endocrine, blood, immune, or other disorders epileptic seizures within the past 6 months also taking B6, or other psychotropic medications at the time of trial commencement participating in other clinical trials Target sample size: 78
Interventions	Intervention 1: high‐dose pyridoxamine plus 20 mg vitamin B1 Intervention 2: low‐dose pyridoxamine plus 20 mg vitamin B1 Comparator: placebo plus 2 0mg vitamin B1
Outcomes	Primary outcomes irritability, measured using the ABC‐Japanese version Secondary outcomes: none reported Timing of outcome assessments: baseline, 4 and 8 weeks
Notes	Contact name: Mitugu Uematsu Contact details: not provided Other clinical trial numbers: UMIN000035172; jRCT2021200001