Perera 2012.

Study characteristics
Methods	Design: parallel trial Comparison: omega‐3/omega‐6 PUFA vs placebo
Participants	Inclusion criteria: 1. children aged 6 to 12 years; 2. treated with MPH and behaviour therapy for more than 6 months for ADHD; 3. refractory to treatment confirmed using the parent version of the SNAP‐IV, clinical interview, and clinical records for the previous 3 months Exclusion criteria: 1. “being registered for less than 6 months”; 2. "hyperactivity was primarily related to intellectual impairment, brain injury, and insult”; 3. “satisfactory outcome in ADHD symptoms, behavior, and school‐based learning”; 4. “missed follow‐up appointments and medication refills” Number of participants: 94 Mean age: 9.3 years Gender: 69 boys and 25 girls ADHD subtypes: not stated Using ADHD drugs at baseline: 100% Baseline scores: not reported Setting: “outpatient treatment program for ADHD” (p748), Sri Lanka, year/s not stated Funding: the preparation of study material was sponsored by Igennus Ltd, Cambridge, UK/Gpristine Pvt Ltd, Sri Lanka
Interventions	Intervention (48 participants): omega‐3/omega‐6 PUFA for 6 months; 1 capsule twice daily of omega‐3 and omega‐6 (Vegepa capsule ‐ fish oil and evening primrose oil, 296.37 mg of omega‐3 and 180.75 mg of omega‐6) Control (46 participants): placebo (sunflower oil) for 6 months; 1 capsule twice daily
Outcomes	Improvement at 3 and 6 months Improvement ‐ score less than total score of 22 on parent‐rated “11‐item checklist” which “assessed symptoms of ADHD and associated behavioral problems and learning difficulties"  ADHD symptoms at 3 and 6 months Parent‐rated “11‐item checklist” which “assessed symptoms of ADHD and associated behavioral problems and learning difficulties”
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: not described
Allocation concealment (selection bias)	Low risk	Quote: ”The researchers and the patients were masked to group allocation, carried out by an independent third person" (p749)
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quotes: "Active treatment or placebo ‐‐‐ were labeled in code”; "A capsule of identical appearance containing sunflower oil was used as the placebo" (p749)
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quotes: Parent‐reported outcomes "Active treatment or placebo ‐‐‐ were labeled in code”; "A capsule of identical appearance containing sunflower oil was used as the placebo" (p749)
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: analysis conducted on 48/49 in PUFA group and 46/49 in placebo group
Selective reporting (reporting bias)	Low risk	Comment: The trial registration, SLCTR/2009/006, listed the following measures: the "1.Diagnosis of behaviour disorder will be made using DSM IV TR criteria. Comorbid disorders will be similarly diagnosed. 2. SNAP IV completed by parent and teacher will be used to further validate the diagnosis and assess the severity of the symptoms. SDQ will be used to assess the specific symptoms of ADHD and its impact. 3. SNAP IV and SDQ will be used to objectively assess the outcome in 1 month, 3 months and 6 months in addition to the clinical assessment" (quote), at 1 month, 3 months and 6 months. In addition, monthly recording of side‐effects were referred to in the paper but were not reported.
Other bias	High risk	Comment: The preparation of study material was sponsored by Igennus Ltd which produced PUFA supplements. The parent‐rated “11‐item checklist” (p749) was not reported as valid or reliable, or both.