Effects of an open-label pilot study with high-dose EPA/DHA concentrates on plasma phospholipids and behavior in children with attention deficit hyperactivity disorder

This was an eight-week, open-label, proof-of-efficacy pilot study. Nine children aged 8–16 were recruited from the patient population under treatment for ADHD-primarily inattentive subtype or ADHD-combined subtype at the Hallowell Center, Sudbury, MA. There were more boys (n = 6) than girls (n = 3). Two-thirds (n = 6) presented with ADHD-combined subtype, and one-third (n = 3) with ADHD-primarily inattentive subtype according to criteria of the Diagnostic Statistical Manual (DSM) IV [17]. Two of the three participants who presented with ADHD-primarily inattentive subtype were girls. Participant characteristics are outlined in Table 1. All participants had an established relationship with the psychiatrist involved in the study. Three participants voluntarily discontinued stimulant medication prior to study initiation with the psychiatrist's approval. The remainder continued with their treatment regime for the duration of the study. There were no medication dosage changes during the course of the eight-week study. Children and parents/guardians provided informed and written assent and consent respectively. Integreview, Houston, TX, approved the study for the use of human subjects in research.

At the start of the study, all participants were instructed to consume two tablespoons (30 mL) of a liquid EPA/DHA concentrate (supplied by the Inflammation Research Foundation) providing 16.2 g of LC omega-3 fatty acids (10.8 g EPA and 5.4 g DHA) per day. The EPA/DHA concentrate dosage was adjusted at week four based on the AA:EPA ratio in the isolated plasma phospholipids as follows: if the AA:EPA ratio was below 1.0, the dosage was decreased to 15 ml (5.4 g EPA, 2.7 g DHA per day), if the AA:EPA ratio was between 1.0 and 1.5 the dosage was decreased to 20 ml (8.1 g EPA, 4 g DHA per day). Isolated plasma phospholipids are not subject to daily fluctuations in dietary intake and are a reliable marker of fatty acid levels [18] and correlate to dietary intake of fatty fish [19‐21] and fish oil supplementation [22, 23]. EPA levels were used to monitor adherence to the supplementation protocol and the participant's parent/guardian was phoned once per week to monitor adherence and adverse effects of the EPA/DHA concentrates. The children and at least one parent/guardian met with the psychiatrist at three time points: baseline (week 0), midpoint (week four) and conclusion (week eight). At the initial (baseline) visit participants were advised to follow a "healthy diet" that encouraged fruits, vegetables and balanced intake of macronutrients at meals and snacks. At each of the three meetings, the psychiatrist conducted behavioral assessments, and a phlebotomist drew blood for fatty acid analysis. Fatty acid analysis of the isolated plasma phospholipids was completed by Nutrasource Diagnostics, Guelph, ON, Canada, as described by Laidlaw and Holub [23].

The ADHD Symptom Checklist-4 (ADHD SC-4) was used to monitor behavioral changes by the psychiatrist at each meeting. Retrospectively the psychiatrist asked the parent/guardian and child each of the checklist questions and also observed symptoms during the process. This questionnaire categorizes behavior as inattention, hyperactivity, oppositional/defiant, and conduct disorder. There was also a section to monitor medication side effects. Inattention and hyperactivity scores can range from 0 to 27 each. Oppositional/defiant scores range from 0 to 24 and conduct disorder from 0 to 3 [24, 25].

The Clinical Global Impression Scale was used by the psychiatrist to rate participants' severity of illness [26]. The scores are derived from a 7-point Likert scale [26]. Severity of illness ranged from 1 as normal (not at all symptomatic), to 7 as among the most symptomatic patients. Although the psychiatrist knew the children were part of a study, he was blind to dosage adjustments and protocol adherence. The parents also completed the short form Conner's Parent's Rating Scale (CPRS) [27‐29] at baseline, week four and week eight. Responses were scored and categorized into 4 groups: oppositional behavior, cognitive problems/inattention, hyperactivity and an ADHD index.

Summary statistics are reported as mean ± SD and medians. Statistical analyses were performed using Stata for Mac (version 9, StataCorp LP, College Station, Texas). Fatty acids, ADHD SC-4, CPRS, and severity of illness were reported for baseline (week 0), midpoint (week four) and at the conclusion of the study (week eight). The non-parametric Friedman test was used to assess changes over time. If the Friedman test was statistically significant at the 0.05 level, then the Wilcoxon signed rank test was used as a post-hoc test to compare changes from baseline to four and eight weeks. Spearman correlations were used to identify a relationship between changes in the primary fatty acid outcome variable, the AA:EPA ratio, and the primary behavioral outcome variable, severity of illness.

Blood was monitored throughout the study to ensure that the AA:EPA ratio was greater than 1.0 because of the potential concern with high-dose EPA/DHA supplementation on prolonged bleeding times; although, a recent study of the Japanese indicated no adverse effects related to EPA intake in patients whose AA:EPA ration was lowered to 0.8 [15]. To maintain the goal AA:EPA ratio between 1.5 and 3 dosage adjustments were made at week four based on fatty acid results. At week four, three participants had an AA:EPA ratio below 1.0 and adjusted their EPA/DHA concentrate dosage to 15 ml per day; two participants had AA:EPA ratios between 1.0 and 1.5 and adjusted their dosage to 20 ml EPA/DHA concentrate; the remaining four participants had an AA:EPA ratio of 1.5 or above, and were instructed to continue with the initial daily dosage. Four of the five participants whose dosage was adjusted at week four increased their AA:EPA ratio by week eight, however the AA:EPA ratio remained less than 3 (Figure 1). Two participants had an AA:EPA ratio less than one at week eight and upon exiting the study were advised to decrease the supplement dosage if they were to continue with the protocol post study.

Overall, at the conclusion of the eight weeks of supplementation, the average EPA and DHA levels in the isolated plasma phospholipids significantly increased by a factor of 9.5 and 2.4 respectively (Table 2). The AA tended to decrease at eight weeks, although the reduction was not significant (p = 0.07). As a consequence of AA and EPA changes, there was a 71% reduction in the mean AA:EPA ratio (20.78 ± 5.26 to 5.95 ± 7.35, p < 0.01) from baseline to week eight. The EPA/DHA concentrate dosage adjustment at week four resulted in the average EPA and DHA levels to increase from week four to eight with a corresponding 42% relative increase (4.19 ± .5.45 to 5.95 ± 7.35, p = 0.07) in the AA:EPA ratio; in contrast, the relative increase in median AA:EPA ratio over the same period was only 16% and better reflects the actual changes among compliant study participants. Nonetheless, these increases demonstrate sensitivity to EPA and DHA supplementation dosage.

The largest AA:EPA reduction for most participants occurred in the first four weeks (Figure 2). Figure 2 shows that one participant's AA:EPA ratio returned to baseline levels at week eight following a reduction at week four. Furthermore, this participant's EPA and DHA levels also returned to near baseline levels, indicating poor compliance from week four to eight. This participant's parent reported poor protocol adherence for the second half of the study, which mimics the fatty acid data. A second participant who refused to consume the liquid was switched to a capsule supplementation and was instructed to consume 24 one-gram capsules (9.6 g EPA and 4.8 g DHA) per day from week two to week eight. The lack of change in the AA:EPA ratio in this participant indicated non-compliance. We chose less than 100% increase in the isolated plasma phospholipids for EPA and DHA as an indicator of poor compliance. The two non-compliant children were not of the same ADHD subtype or gender. All other participants had greater than a 100% increase in both EPA and DHA levels at the conclusion of the study and were considered compliant with study supplementation protocol.

One participant reported loose stools while taking 30 ml of the liquid EPA/DHA concentrate per day. At week four, the dosage was decreased to 15 ml per day with no subsequent adverse events. No observational effects on bleeding were reported by the parents. One child had adverse effects (tics) related to stimulant medication prior to study initiation that continued throughout the study. Sleep disturbance is another know adverse effect of medication for the treatment for ADHD [30]; four of the nine children had improvements in sleep noted by the parents.

All categories of the ADHD SC-4 significantly improved by week eight. Specifically, inattention, hyperactivity, oppositional/defiant behavior and conduct disorder all significantly improved over the course of the study (Table 3). The CPRS showed significant improvements (p < 0.05) in all four categories (oppositional behavior, cognitive problems/inattention, hyperactivity, and the ADHD index) over the eight week study as well (Table 3). The severity of illness score, assessed by the psychiatrist, tended to improve (p = 0.08) over time. On average, the severity of illness score decreased by 1 point from 4.4 (moderately symptomatic) to 3.3 (mildly symptomatic). The two subjects who were identified as non-compliant from parental reports and fatty acid levels were the only participants who were scored a 5 (markedly symptomatic) at baseline and week eight.

There was a significant positive correlation of the percent change in AA:EPA ratio with the percent change in severity of illness (Rho = 0.7638, p = 0.027). However, the AA:EPA ratio did not significantly correlate with the ADHD SC-4 or CPRS categories.