Objective : To investigate the effects of 15 mg/kg bw/d of Lemon Verbena extract, in comparison to placebo, on the attention deficit hyperactivity disorder (ADHD) type behaviour, cognitive function and mood of children who do not have a diagnosis of ADHD, but who exhibit high scores on the Inattention and Hyperactivity/Impulsivity scales of the Conners 3 Parent Rating Scale (Short) [Conners 3-P(S)].

Methods : The study followed a randomised, double-blind, placebo-controlled, parallel groups design.
Pre-screening for the behaviour inclusion criterion (Conners 3-P(S)] took place online via the questionnaire platform Qualtrics. Individuals who met the Conners 3 criterion proceeded to have an initial remote screening session followed by visits to the laboratory on four separate occasions: an introductory/training visit and three active testing visits (Day -1, Day 28, and Day 56).
The remote screening session was completed via video/telephone call and comprised: briefing on requirements of the study, obtaining of informed assent (child) and consent (parent/guardian) via completion of an online consent form, health screening, collection of demographic data and completion of the Caffeine Consumption Questionnaire (CCQ). The introductory/training visit to the laboratory began with physiological eligibility measures that could be completed remotely (e.g. height and weight) followed by training on the completion of the cognitive and mood measures.

Conclusion : The Lemon Verbena treatment was safe and well-tolerated by participants, with no unexpected safety events. Considering this study is the first to investigate the effects of a Lemon Verbena extract in this population, the results are promising and open up a new avenue of ADHD type behaviour management with a herbal supplement.