Complementary and alternative medicine in ADHD treatment: more soundly designed clinical trials needed

Abstract

We read with great interest the article [1] by Dehbokri et al. published in the Journal recently. The authors carried out a double-blind, randomized clinical trials to study the effects of vitamin D supplementation on children with attention deficit hyperactivity disorder (ADHD) for 6 weeks. The results showed that vitamin D could improve ADHD symptoms with a particular effect on inattention symptoms. It is a significant report to examine whether vitamin D supplementation can benefit ADHD symptoms, which draw our attentions on the interesting topic of vitamin and mineral supplementation in the treatment of ADHD. ADHD is a neuro-developmental disorder defined by DSM-5 [2], which means the functional impairments of ADHD symptoms to individuals would not limited in childhood [3]. Currently, the treatment strategies recommended by most guidelines include psychopharmacological drugs and behavioral modifications that have been proven effective [4–6]. Behavioral modifications can benefit young children and those with mild ADHD symptoms [4]. For those with severe symptoms and age over 12 years, monotherapy with behavioral modifications may not work well, and psychopharmacological drugs are indispensable [4, 5]. The most common medications offered to them are stimulants as any type of methylphenidate and dextroamphetamine, and nonstimulants as atomoxetine, clonidine and guanfacine [4]. Although all these medications have been approved by Food and Drug Administration to treat ADHD, a proportion (up to 30%) of children may undergo possibly adverse effects, including decreased appetite, abdominal pain, headache and insomnia [7]. Furthermore, due to this disease being lifelong, the use of medications is long term [5]. All the issues of drug use and long-term administration will bring out the worries of parents and caregivers about the safety and effectiveness of medications. Many pediatricians and child psychiatrists also take the issues burdensome [8]. From this point, the patients, families and professionals do not stop to search other potential treatment methods for ADHD that are named complementary and alternative medicine (CAM) [1, 9, 10]. Generally, CAM is used as a mono-treatment method or along with standard medical treatments but is not considered to be standard treatments [11–13]. They always include vitamin and mineral supplements, nutritional interventions, herbal and natural products, acupuncture, biofeedback, massage and yoga, homeopathy, etc [10]. The frequency of using CAM in children who have ADHD ranges between 12 and 64% [14]. Parents perceive a belief that CAM is “natural” therapies, and safe and side effect free, which contributes to their wide use. However, there still has been controversy about the effectiveness, safety and costs of use of these interventions. Up to date, vitamin and mineral supplements are most popular in CAM for ADHD [15]. We take it as an example to elucidate the conditions of researches. There are several features of supplement method as food based and derived, accessibility, ease of use, and the concept of they are safe. Zinc supplementation for ADHD has been studied in the past two decades [16–18]. A group of studies showed that children with ADHD have low zinc levels compared with normal controls [16, 17]. Then, zinc supplementation is hypothesized to improve the ADHD symptoms in those children with low zinc levels. An increasing body of studies tried to address this topic, including observational self-controlled [19], observational cohort [20] and randomized, placebocontrolled trials (RCT) (Table 1) [21–25]. Unfortunately, they have provided conflicting evidence of efficacy of zinc supplementation either as an adjunct to psychostimulant treatment or as monotherapy. One largest sample-sized RCT in Turkey showed zinc supplementation with a dosage of 150 mg/day benefited children with ADHD compared to * Rong-Wang Yang [email protected]