The study will consist of two main elements: the enrollment of 72 children aged 6-11 years with ASD and low language competency to receive a thrice-weekly one hour language intervention for 12 weeks; and, beginning at the same time, subjects will be equally randomized to receive either aripiprazole (Abilify) (flexibly dosed from 2-10 mg per day) or placebo for 12 weeks.

Following screening for eligibility and baseline, study visits will be scheduled three times per week, with 2 sessions on-site at UCLA and one at home for parent training (allowing flexibility, as needed); study physician visits will occur once weekly for 6 weeks, then biweekly. Screening procedures may be completed in one or two visits, and measures obtained in other UCLA clinical or research setting may be used if assessments were done within one month of screening. Major outcome assessments will occur at baseline (Week 0), mid-point (Week 6), and final week (Week 12) by study personnel blind to visit number and drug group assignment; minor assessments will occur weekly along with study physician assessments occurring weekly for side effect and compliance checks. EEG will occur at or prior to baseline and at Visit 36 (Wk12). Arrangements will be made to transfer participants to standard clinical care following visit 36. Six months after visit 36, families will be seen for final follow-up assessments of language usage, social communication, overall functioning, health and ongoing treatment.

Inclusion criteria:

• boys and girls ages 5-11 years;
• criteria for autistic disorder or PDD-NOS as defined by DSM-IV-TR and confirmed by clinical examination and ADI-R, ADOS;
• low language usage as defined by <30 functional words obtained from a natural language sample, parent report, and standardized tests;
• present placement in a comprehensive educational/intervention setting.

Exclusion criteria:

• any medical condition that would interfere with intervention outcomes during a 12 week study period (eg., active seizures within 3 months);
• genetic disorders such as Fragile X, Down syndrome, or tuberous sclerosis;
• sensory impairments such as deafness or blindness;
• existing or anticipated need for concomitant psychotropic medication (specifically stimulants, atomoxetine) during study participation( allowed medication include: antidepressants, anticonvulsants, guanfacine, clonidine, supplements, melatonin, diphenhydramine);
• severe aggression or self-injurious behavior;
• DQ <18 months as assessed by the Leiter-Revised or Mullen.