• Effectiveness of atomoxetine versus placebo in treating children with autism or PDDNOS who exhibit symptoms of ADHD; Parent-rated Swann Nolan and Pelham Questionnaire (SNAP-IV) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: Yes ]
  
• Effectiveness of parent management versus no parent management compliance [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Home and School Situations Questionnaires and the Standardized Observation Assessment Procedure [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  

• Clinical Global Impressions CGI) - Improvement and severity [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Teacher-rated SNAP-IV [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Parent- and teacher-rated Aberrant Behavior Checklists (ABCs) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• CGI Severity Adverse Events Questionnaire [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: Yes ]
  
• Vital signs (blood pressure, pulse, height, weight) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Labs (electrocardiogram, urinalysis, complete blood count, liver function tests) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Cognitive performance (Continuous Performance Test, Delay of Gratification, Speeded Classification Test, Cancellation Task) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Parenting Stress Index (Short Form) [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  
• Parent Treatment Preference Questionnaire [ Time Frame: Measured at Week 10 and Week 24 of extension phase ] [ Designated as safety issue: No ]
  

Autism and pervasive developmental disorder not otherwise specified (PDDNOS), an autism spectrum disorder, are brain development disorders characterized by abnormalities in communication, social interactions, and range of interests. Overactivity and inattention, both symptoms of attention deficit hyperactivity disorder (ADHD), are commonly reported among children with autism. Recent data have suggested that at least 14% of children with autism are treated for ADHD symptoms, typically with stimulant medication. However, response rates to stimulant medication are poorer among children with autism than among typically developing children with ADHD, suggesting a substantial need for potential alternative treatment options. Previous studies have shown that training programs that teach parents ways to address adaptive behavior and behavioral problems can be effective in improving symptoms of autism and ADHD in children. Parent training, in combination with the nonstimulant ADHD medication atomoxetine, may be the best way to improve emotional and attention-related problems in children with autism and ADHD. This study will evaluate the effectiveness of the medication atomoxetine, with and without parent management training (PMT), in treating children with autism or PDDNOS who have symptoms of ADHD.

Participation in this study will last 9 months and will include two phases. Phase 1 will last 12 weeks. After screening, all eligible child participants will undergo baseline assessments that will include tests of attention and/or memory on a computer system, vital sign measurements, and a review of past medications. Parent participants will also complete questionnaires about their child's behavior and symptoms and a review of any previous parent training experiences.

Participants will then be assigned randomly to one of four treatment groups: atomoxetine plus PMT, atomoxetine alone, placebo plus PMT, or placebo alone. Child participants will take their assigned study medication twice daily for 10 weeks and will attend weekly clinic visits. During these visits, child participants will undergo vital sign measurements, possible medication adjustments, and some of the baseline learning testing. Parent participants will be asked questions about their child's side effects and behavior. Participants assigned to also receive PMT will individually meet with a clinician weekly for 10 weeks. The sessions involving a parent and child or parent alone will include parenting instruction, practice activities, behavior rehearsal with feedback from the behavior therapist, and role-playing of specific skills. Parents will also be given at-home homework assignments that will involve practicing techniques learned in sessions and collecting information on their child's behavior. At the end of Phase 1, all participants will repeat the baseline assessments and children will undergo a physical exam.

Any child participants who have shown improvement after Phase 1 will be invited to participate in Phase 2, which will last 24 weeks. Child participants will continue to take their assigned medications from Phase 1 and, if applicable, will continue PMT sessions once a month. They will attend 6 monthly clinic visits that will involve the same procedures conducted in Phase 1 visits. Upon completing the 24 additional weeks of treatment, all participants will undergo repeat baseline assessments.