After removal of duplication Article search: Database: Pubmed Keyword: (omega-3 fatty acids or HUFAs or eicosapentaenoic acid or docosahexaenoic acid or ethyl-eicosapentaenoic acid or lipoic acid or linoleic acid) AND (autism or autism spectrum disorder or ASD or Asperger or Pervasive development disorder or PPD) Limits: No Date: date available to June 21st, 2017 (n=140) Article search: Database: ScienceDirect Keyword(omega-3 fatty acids) AND (autism OR autism spectrum disorder) Filter: No Date: date available to June 21st, 2017 (n=493) Article search: Database: Cochrane Library Keyword: (omega-3 fatty acids or HUFAs or eicosapentaenoic acid or docosahexaenoic acid or ethyl-eicosapentaenoic acid or lipoic acid or linoleic acid) AND (autism or autism spectrum disorder or ASD or Asperger or Pervasive development disorder or PPD) Limits: No Date: date available to June 21st, 2017 (n=25) Article search: Database: ClinicalTrials.gov Keyword: (omega-3 fatty acids or HUFAs or eicosapentaenoic acid or docosahexaenoic acid or ethyl-eicosapentaenoic acid or lipoic acid or linoleic acid) AND (autism or autism spectrum disorder or ASD or Asperger or Pervasive development disorder or PPD) Limits: No Date: date available to June 21st, 2017 (n=9) Identification Screening After removal of duplication (n=525) Excluding articles (n=491) Figure S1 Eligibility Eligibility (n=34) Not meeting inclusion criteria (n=28) Included Figure S1 Included articles in meta-analysis (n=6)

Figure S2 Figure supplement figure 2A funnel plot of ABC hyperactivities subscale

Figure supplement figure 2B funnel plot of ABC lethargy subscale

Figure supplement figure 2C funnel plot of ABC stereotypy subscale

Figure supplement figure 2D funnel plot of ABC inappropriate speech subscale

Figure supplement figure 2E funnel plot of ABC irritability subscale

Figure supplement figure 2F funnel plot of clinical improvement via CGI-I measurement

Figure supplement figure 2G funnel plot of SRS total

Figure supplement figure 2H funnel plot of drop out rate

Figure supplement figure 2I funnel plot of discontinue treatment due to side effect