Guanfacine Extended Release for the Reduction of Aggression and Self-injurious Behavior Associated With Prader-Willi Syndrome

Initial dose for all participants will be 1mg per day. If the medication is well tolerated, the dose can be raised to 2 mg until day 28 and increased to 3 mg for the remaining 4 weeks in the trial. The dose schedule will not be fixed., the treating clinician can delay a planned increase or lower the dose to manage adverse effects. At week 8 timepoint, the study will be unblinded.and subjects will continue treatment for 8 weeks.

Placebo will be administered concurrently with GXR during trials.