Although psychostimulant is the first line of drug to treat Attention Deficit Hyperactivity Disorder, (ADHD), actually there are 10-20% ADHD patient do not response well to current medication. Most of parents of children with ADHD in Taiwan dislike to use psychostimulant. We expect that GlyTI-M will have better efficacy than placebo to reduce ADHD symptoms. This study will also help us to understand the mechanism of ADHD and give a way to develop new drug and also a more possible way to treat ADHD children under 6 years old.

The accumulated neuro-image, hereditary and animal studies showed the correlation between glutamate transport dysfunction and ADHD psychopathology. However, there is limited clinical trial to testify the effect of modulating the NMDA receptor function of glutamate to treat ADHD.

GlyTI-M is an endogenous Glycine transporter I inhibitor, and it acts on the glutamatergic synapse to modulate the neurotransmission of N-Methyl-D-Aspertate (NMDA) receptor. This study aims to explore the effect of GlyTI-M among children with ADHD.

Inclusion Criteria:

• Fulfill the criteria of ADHD according to the Diagnostic and Statistic Manual, fourth edition (DSM-IV).
• Subjects and parents agree to participate in the study and provide informed consent.

Exclusion Criteria:

• Autism, Mental retardation.
• inability to follow protocol.