Early identification of stimulant treatment responders, partial responders and non-responders using objective measures in children and adolescents with hyperkinetic disorder

Background: The aim of this study was to evaluate stimulant medication response following a single dose of methylphenidate (MPH) in children and young people with hyperkinetic disorder using infrared motion analysis combined with a continuous performance task (QbTest system) as objective measures. The hypothesis was put forward that a moderate testdose of stimulant medication could determine a robust treatment response, partial response and non-response in relation to activity, attention and impulse control measures. Methods: The study included 44 children and young people between the ages of 7-18 years with a diagnosis of hyperkinetic disorder (F90 & F90.1). A single dose-protocol incorporated the time course effects of both immediate release MPH and extended release MPH (Concerta XL, Equasym XL) to determine comparable peak efficacy periods post intake. Results: A robust treatment response with objective measures reverting to the population mean was found in 37 participants (84%). Three participants (7%) demonstrated a partial response to MPH and four participants (9%) were determined as non-responders due to deteriorating activity measures together with no improvements in attention and impulse control measures. Conclusion: Objective measures provide early into prescribing the opportunity to measure treatment response and monitor adverse reactions to stimulant medication. Most treatment responders demonstrated an effective response to MPH on a moderate testdose facilitating a swift and more optimal titration process.

Strigolactone analogues induce suicidal seed germination of Striga spp. in soil

Striga hermonthica and Striga asiatica are obligate root parasites that cause serious problems in the production of staple cereal crops in Africa. Because of the high levels of infestation, there is an urgent need to control these weeds. A potentially useful control option is depletion of the soil seed bank by suicidal germination, which involves germination of the seeds in the absence of host plants. Suicidal germination is often mentioned in the literature, but not considered realistic, because of the alleged untimely decomposition of the stimulants in the soil, despite the fact that some encouraging results were reported around 1980. The alleged instability has prevented active research in this direction for the past 20–25 years. Five newly designed synthetic germination stimulants were investigated as candidates for suicidal germination. An important issue is the persistence of these stimulants in soil. Packets with Striga spp. seeds were put in pots with soil and then treated with aqueous solutions of the stimulants. All five compounds induced germination under these conditions, with percentages varying between 18% and 98% depending on stimulant and species. There were no noticeable signs of decomposition of the stimulants. The best performing stimulant is derived from 1-tetralone. We conclude that synthetic strigolactones analogues have excellent prospects for use in combating parasitic weeds. Further testing will be needed to evaluate whether such prospects can be realised in the field.

Caught in the eye of the storm: a qualitative study of views and experiences of planned drug holidays from methylphenidate in child and adolescent ADHD treatment

Background: Attention deficit hyperactivity disorder (ADHD) can be treated with stimulant medication such as methylphenidate. Although effective, methylphenidate can cause serious side-effects, including suppressed appetite, growth retardation and sleep problems. A drug holiday is a deliberate interruption of pharmacotherapy for a defined period of time and for a specific clinical purpose, for example for appeasing side-effects. Whilst some international guidelines recommend introducing drug holidays in ADHD treatment, this is not practised routinely. Our aim was to examine the views and experiences of planned drug holidays from methylphenidate with adults who have responsibility for treatment decisions in children and adolescents with ADHD. Method: In-depth interviews were carried out. Child and Adolescent Mental Health Services (CAMHS) practitioners (n=8), General Practitioners (n=8), teachers (n=5), and mothers of children with ADHD (n=4) were interviewed in a UK setting. Interview transcripts were analysed using grounded theory. Results: Methylphenidate eases the experience of the child amid problems at home and at school and once started is mostly continued long-term. Some families do practise short-term drug holidays at weekends and longer-term ones during school holidays. The decision to introduce drug holidays is influenced by the child’s academic progress, the parents’ ability to cope with the child, as well as medication beliefs. Trialling a drug holiday is thought to allow older children to self-assess their ability to manage without medication when they show signs of wanting to discontinue treatment prematurely. Conclusions: Planned drug holidays could address premature treatment cessation by enabling adolescents to assess repercussions under medical supervision.