Study Comparing Two Doses of MG01CI and Placebo in Adults With Predominantly Inattentive Attention Deficit Hyperactivity Disorder

Inclusion Criteria: 1. Adult men and women, 18 to 55 years old 2. Diagnosed with predominantly inattentive ADHD based on DSM-IV criteria for ADHD as assessed by the Adult ADHD Clinician Diagnostic Scale (ACDS V1.2); 3. Clinical severity of at least a moderate level (Clinical Global Impression score of 4 or above) 4. TOVA ADHD score of -1.8 or below at Screening /Baseline 5. Women with childbearing potential must agree to use effective contraceptive and have negative urine pregnancy test at screening visit 6. Able to attend the clinic regularly and reliably 7. Able to swallow tablets/capsules 8. Able to understand, read, write and speak Hebrew fluently to complete study related materials 9. Able to understand and sign written informed consent to participate in the study Exclusion Criteria: 1. Subjects with ADHD not otherwise specified (NOS) diagnosis 2. Subjects with combined type or predominantly hyperactive impulsive ADHD diagnoses 3. Subjects with current Axis I diagnosis on SCID 4. Subjects with lifetime bipolar or psychosis 5. Subjects in treatment for Axis I disorders, even if the disorder is remitted 6. Subjects who were non-responders to at least two adequately administered ADHD treatments 7. Subjects with any medical or psychiatric condition 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 8. Any prescription or non-prescription ADHD medications during the 14 days (for stimulants) or 28 days (for non-stimulants and other psychotropics) prior to the screening visit 9. Known or suspected HIV-positive or with advanced diseases such as AIDS, Hepatitis C, Hepatitis B or tuberculosis 10. History of allergy or sensitivity to B complex vitamins 11. History or suspicion of PDD, NLD or other psychotic conditions 12. Use of Vitamin B throughout the study (either alone or in any multi-vitamin) 13. Use of ADHD medications throughout the study 14. Use of any psychotropic medications throughout the study 15. Use of investigational medication/treatment in the past 30 days prior to the screening visit 16. Use of any medication or food supplement unless cleared by the medical monitor during the 14-day period before randomization 17. 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 significantly changing consumption of caffeine during the study. 18. Suicidality, defined as active ideation, intent or plan, or any lifetime attempt (CSSRS) 19. Subjects who cannot complete any study instruments or questionnaires 20. Any relation to the Sponsor, Investigator or study staff 21. 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. 22. 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 23. Women of childbearing potential must test negative for pregnancy at the time of enrollment based on a serum pregnancy test and agree to use a reliable method of birth control (e.g., oral contraceptives or Norplant®; a reliable barrier method of birth control \[diaphragms with contraceptive jelly; cervical caps with contraceptive jelly; condoms with contraceptive foam\]; intrauterine devices; partner with vasectomy; or abstinence) during the study. Note that this inclusion criterion applies only to females of childbearing potential. Females of childbearing potential are defined as women not surgically sterilized and between menarche and 2 years post-menopause