We have identified 16* articles published in English-language, peer-reviewed journals which evaluated the efficacy of omega-3 fatty acids as an intervention for people on the autism spectrum. Three of those articles (Boone et al, 2017; Keim et al 2018; Sheppard et al, 2017) appeared to describe the same study.
The studies we found included more than 300 individuals aged from three to forty - but only one of these studies looked at adults, the majority looked at children and adolescents. A small number of studies also included people with other conditions, such as ADHD.
The majority of the group studies were randomised controlled trials which compared omega-3 supplements with a placebo. One of the studies (Meguid et al, 2008) used a supplement which included omega-6 alongside the omega-3. Another of the studies (Boone et al, 2017) used a supplement which included omega-6 and omega-9 alongside the omega-3. One of the randomised controlled studies (Johnson et al, 2010) compared omega-3 with a sugar-free diet. The four single case designs were open trials which did not compare omega-3 with anything else.
The length of intervention varied from six weeks to 16 weeks but in most cases it lasted between six weeks and three months. The dosage varied from 0.09 grams per day to 1.5 grams per day but in most cases the dosage varied between 1and 1.5 grams per day.
*Please note: We have not included articles with less than three participants on the autism spectrum or articles which did not examine the efficacy of omega-3 fatty acids as an intervention for people on the autism spectrum.