The purpose of this study was to investigate the effects of prevent-teach-reinforce positive behavior
support on class participation behaviors and class disruption behaviors of the elementary school student at
risk for ADHD. The subject was a elementary school male student at risk for ADHD. To demonstrate
the effect of this study, multiple probe baseline design across settings was conducted. Based on Functional
Behavior Assessment for the subject, prevent-teach-reinforce positive behavior support(intervention of
antecedents and setting events, alternative behavior instruction, consequences and system change) were
developed and implemented in a regular classroom and special education classroom. The results of this
study were as follows: First, the prevent-teach-reinforce positive behavior support was effective in
increasing the class participation behaviors of the student ar risk for ADHD. Second, the intervention was
effective in decreasing the class disruption behaviors of the student ar risk for ADHD. The effects of the
intervention were maintained after the completion of the intervention and generalized. These results imply
that the prevent-teach-reinforce positive behavior support is helpful to improve class participation behaviors
of the elementary school student at risk for ADHD and that early intervention is important for the
student at risk for ADHD.