Clinical Efficacy & Safety, of Metadoxine (MG01CI) Extended Release in Attention-Deficit Hyperactivity Disorder (ADHD)

Inclusion Criteria: 1. Adult males and females, 18 to 50 years old, inclusive, at screening visit 2. Diagnosed with ADHD based on 1. DSM-IV criteria for ADHD as assessed by the Adult ADHD Clinician Diagnostic Scale (ACDS V1.2) 2. SCID clinical interview 3. Clinical severity of at least a moderate level (Clinical Global Impression score of 4 or above) 4. Female subjects with childbearing potential must agree to use effective contraceptive and have negative urine pregnancy test at screening visit 5. Able to attend the clinic regularly and reliably 6. Able to swallow tablets/capsules 7. Able to understand, read, write and speak Hebrew fluently to complete study related materials 8. Able to understand and sign written informed consent to participate in the study Exclusion Criteria: 1. Subjects who were non-responder to at least two ADHD treatments 2. Subjects with any medical or psychiatric condition (e.g. schizophrenia, personality disorder as diagnosed by DSM-IV) or clinical significant or unstable medical or surgical condition that may preclude safe and complete study participation as determined by medical history, physical examination, neurological exam, laboratory tests or ECG or based on the opinion of the Investigator; common diseases such as hypertension, type 2 diabetes mellitus, hyperlipidemia, etc. are allowed per the Investigator's judgment, as long as they are stable and controlled by medical therapy that is constant for at least 8 weeks prior to randomization and throughout the study 3. Any prescription or non-prescription ADHD medications during the 7 days prior to the screening visit 4. Known or suspected HIV-positive or with advanced diseases such as AIDS, Hepatitis C, Hepatitis B or tuberculosis 5. History of allergy or sensitivity to B complex vitamins 6. History or suspicion of PDD, NLD or other psychotic conditions 7. Use of Vitamin B throughout the study 8. Use of ADHD medications throughout the study 9. Use of any psychiatric medications throughout the study 10. Use of investigational medication/treatment in the past 30 days prior to the screening visit per the discretion of the Investigator 11. Use of any medication or food supplement not considered acceptable by the clinical Investigator or the medical monitor during the 14-day period before randomization 12. Current (or history within the last 6 months) of drug dependence or substance abuse disorder according to DSM-IV-TR criteria (excluding nicotine). Subjects should also agree to refrain from consuming abnormally high amounts of caffeine during the study. 13. Suicidality, defined as either active suicidal plan/intent or active suicidal thoughts, in the 6 months before the Screening Visit or no lifetime suicide attempt. 14. Blind subjects 15. Any relation to the Sponsor, Investigator or study staff 16. Any condition, which in the opinion of the Principal Investigator would place the subject at risk or influence the conduct of the study or interpretation of results, including (but not limited to) abnormally low intellectual capacity. 17. Subjects who cannot fully comprehend the implications of the protocol or comply with its requirements or are capable to follow the study schedule for any reason 18. Pregnancy, lactation or inadequate contraceptive method \-