Daily supplementation with lemon verbena extract decreases subjective energy and parental reports of hyperactivity in children displaying sub-clinical attention deficit hyperactivity disorder-type behaviours: A randomised controlled trial.

BACKGROUND

Current treatment options for attention deficit hyperactivity disorder (ADHD) are limited by factors such as adherence and cost, whilst no treatment options are available for sub-clinical or undiagnosed ADHD. Herbal preparations may therefore offer an alternative approach to the management of symptoms; Paláu (lemon verbena) is a promising candidate.

AIM

To assess the behavioural, cognitive, psychological and physiological effects of 56 days of supplementation with lemon verbena extract (LVE) in children exhibiting symptoms of ADHD at the sub-clinical level.

METHODS

This exploratory study followed a randomised, double-blind parallel groups design wherein 120 healthy participants aged 8-17 years received 15 mg/kg bw/d LVE or matched placebo for 56 days. Behavioural, cognitive, mood and physiological measures were collected in the lab at baseline and 28 and 56 days post-dose. Parents also evaluated the child's behaviour throughout the study.

RESULTS

Participants who received LVE reported greater subjective fatigue, defined as reduced energy levels according to the Profile of Mood States subscale, without impairments in cognitive performance across the 56-day intervention and lower depression symptoms on day 56, compared to placebo. The effect of LVE on parent ratings of hyperactive/impulsive behaviour also approached significance with fewer concerns being reported following the active treatment. Exploratory analyses showed further benefits to cognition and mood.

CONCLUSIONS

This study revealed novel, beneficial effects of LVE supplementation in children exhibiting a high frequency of behaviours characteristic of ADHD. Overall, LVE was safe and well-tolerated by participants, with no unexpected safety events.