Methods of treating a developmental disorder described here include administering toa patient in need thereof about 0.05 mg to about 30 mg 15 gaboxadol or pharmaceutically acceptable salt there ofwherein the method provides improvement in next day functioning. Methods of treating a developmental disorder described here include administering toa patient in need there of about 0.05 mg to about 30 mg Gaboxadol or pharmaceutically acceptable salt there ofwherein the method provides improvemeNT in the 20 patient for more than 6 hours after administration to the patient. Methods of treating a development disorder are described here which includes administration to a patient in need there of gaboxadol or pharmaceutically acceptable salt thereof where the method provides an vivo plasma profile including a Cmax less than about 400 ng / ml and where the method provides 25 improvement in the patient for more than 6 hours after administration of the Gaboxadol ora pharmaceuticallyacceptable salt thereof. Methods oftreating a developmental disorder are described herein which include administering toa patient in need thereof gaboxadol ora pharmaceutically acceptable salt itself within the method provides an in vivo plasma profile comprising a AUC 6 • 12 30 ofless than about 900 ng • hriml and accordingly the method provides improvement in the patient for more than 6 hours after administration of the gaboxadol ora pharmaceutically acceptable salt thereof. Methods oftreatinga developmental disorder are described here which include administering toa patient in need thereof a first pharmaceutical composition comprising Gaboxadol or pharmaceutically acceptable salt thereof anda second pharmaceutical composition comprising Gaboxadol or pharmaceutically 5.Acceptable salt thereofwherein the second pharmaceutical Composition provides an in vivo plasma profile comparing a mean auco OO of at least 20% less than the first pharmaceutical composition Strokethe developmental disorder may be an A
