Omega-3 Fatty Acids Monotherapy in Children and Adolescents With Autism Spectrum Disorders

Inclusion 1. Male or female participants between 6 and 17 years of age, inclusive. 2. Fulfills diagnosis of autism spectrum disorders by meeting DSM-IV-TR PDD diagnostic criteria of autistic disorder, Asperger's disorder, or PDD-NOS as established by clinical interview assisted by MGH PDD Symptom Checklist. 3. Participants with at least moderate symptom severity of ASD as reflected by SRS score ≥ 85 and CGI-PDD severity score of ≥ 4 (moderately ill). 4. Subjects must be psychotropic drug-free for a minimum of four weeks prior to the baseline visit. 5. Subjects with mood, anxiety, or disruptive behavior disorders will be allowed to participate in the study provided they do not meet any exclusionary criteria. Exclusion 1. I.Q. \< 85. 2. DSM-IV-TR PDD diagnoses of Rett's disorder, and childhood disintegrative disorder. 3. Current diagnosis of a psychotic disorder or unstable mood or anxiety disorders as determined by the clinician. 4. Subject with marked severity of symptoms as suggested by the score of ≥ 5 (markedly ill) on CGI severity subscale for respective comorbid psychiatric disorders. 5. Clinically unstable psychiatric condition judged to be at a serious risk to self or others as determined by the clinician. 6. History of substance use (except nicotine or caffeine) within past 3 months, determined to be clinically significant by clinician. 7. Urine drug screen positive for substances of abuse. 8. Non-febrile seizures without a clear and resolved etiology in last month. 9. Subjects with a medical condition or treatment that will either jeopardize subject safety or affect the scientific merit of the study, including: 1. Pregnant or nursing females; 2. Organic brain disorders; 3. Uncorrected hypothyroidism or hyperthyroidism, as determined by study clinician; 4. Untreated and/or unstable diabetes; 5. Subjects with a clinically significant abnormality according to cardiology consultation (ECGs with clinically concerning intervals including PR, QTC, QRS, will be reviewed by cardiology). 6. History of renal or hepatic impairment determined to be clinically significant by clinician. 10. Serious, unstable systemic illness including hepatic, renal, gastroenterological, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease, as determined by clinician. 11. Any other concomitant medication with primary central nervous system activity other than specified in the Concomitant Medication section of the protocol. 12. Subjects who have difficulty swallowing pills. 13. History of known allergy to Omega-3 fatty acids, multiple drug allergies, or severe allergies. 14. A non-responder of, or history of intolerance to Omega-3 fatty acids, after treatment at an adequate dose and duration as determined by the clinician.