Recently, the role of herbal medicines in human psychiatry has been gaining momentum, giving rise to the relatively new field of “Nutritional Psychiatry” (Jacka FN, 2017, EBioMedicine). This emerging field of research has focused on developing a comprehensive, cohesive, and scientifically rigorous evidence base to shift conceptual thinking around the role of diet and nutrition in mental health.

ADHD and Current Treatments
Attention-deficit hyperactivity disorder (ADHD) is a common childhood-onset psychiatric disorder that may affect an individual throughout life. ADHD patients show phenotypic heterogeneity; the disorder is characterized by impaired sustained attention, hyperactivity, and increased impulsivity. In addition, ADHD is associated with social, academic, vocational, and mental health problems. Approximately 3-5% of school children and adolescents are affected by ADHD; the prevalence is higher in boys than girls.

The pathophysiology of ADHD remains elusive. The dysfunction of dopaminergic and noradrenergic neurotransmission is considered a major neurobiological cause of ADHD. Several treatment strategies, such as nonpharmacological (behavioral/psychosocial) and pharmacological interventions or a combination of both have been suggested for ADHD treatment.

Behavioral therapy shows promise, especially in youth and young adult ADHD patients. Stimulant medications such as methylphenidate are frequently administered in individuals with ADHD, but they are not always effective. Due to serious limitations of safety and efficacy of current pharmacological interventions, there has been growing interest in the development of alternative/adjunct treatments such as natural products, including botanical or herbal medicines, vitamins, minerals, and amino acids for ADHD management/treatment.

Alternative Options
Developing over concerns of adverse effects of pharmacotherapy, research on alternative treatment strategies including the use of nutritional and herbal supplements has been prompted. It has been identified that 12% of children with ADHD are using complementary or alternative medicines including dietary supplements. ADHD has, for example, been associated with a Western-style diet high in fat and refined sugars, and low in omega-3 polyunsaturated fatty acids (omega-3 PUFAs) and fiber. Considering this connection, nutritional supplementation has been proposed for the treatment of ADHD, mainly with PUFAs, vitamins and minerals.

PUFAs: PUFAs play an important role in neuronal development and functioning of the central nervous system. The brain is rich in long-chain (LC) omega-3 and omega-6 PUFAs, particularly docosahexaenoic acid (DHA) and arachidonic acid (AA). The human brain cannot synthesize PUFAs internally and therefore requires supplementation through the diet (essential fatty acids (EFAs). Positive effects include improvement of neuronal processes and cognitive function by modulating the neuronal membrane, which can affect membrane receptors, neurotransmission, signal transduction, and neural plasticity.

Zinc: Zinc homeostasis in the brain is closely associated with neuronal activity, and considered an endogenous neuromodulator in synaptic neurotransmission. Many studies including meta-analyses suggested that zinc deficiency may be linked with hyperactivity and may also be involved in the pathophysiology of ADHD in children.

Iron and Magnesium: Iron as a cofactor for tyrosine hydroxylase, the rate-limiting enzyme of monoamine synthesis, is directly involved in the regulation of dopamine and noradrenaline synthesis. Therefore, iron deficiency in the brain has been suggested to play a role in the pathophysiology of ADHD. Similarly, magnesium is involved in the protection of neuronal cell membranes and the modulation of neurotransmitter release in the brain.

Botanicals: Several intervention trials with mono or combination herbs have shown very promising results for the prevention and treatment of ADHD. Among them, French Maritime pine bark, Bacopa monnieri, Ginseng, Ginkgo biloba, and valerian extract are considered to be the most promising botanical alternatives. Given the multifactorial characteristics of ADHD, the management of this disorder may benefit from a combinational approach, such as two or more herbs.

Conclusion
Since ADHD is a complex disorder having multiple causes, the use of natural product-derived treatments alone may not sufficiently be positioned to manage ADHD symptoms. Although the use of natural medications for ADHD has been considered as a “safer” approach, “herb-nutra” products are still far from being considered as standalone ADHD treatments due to the lack of comprehensive and appropriately controlled clinical studies that demonstrate both efficacy and safety. 

References

1. Ahn, J et al. 2016. Natural Product-Derived Treatments for Attention-deficit/Hyperactivity Disorder: Safety, Efficacy, and Therapeutic Potential of Combination Therapy. Neural Plasticity, Volume 2016, Article ID 1320423, 18 pages.
2. Jacka, FN. 2017. Nutritional Psychiatry: Where to Next? EBioMedicine 17 (2017) 24–29.
3. Lange, KW et al. 2017. The Role of Nutritional Supplements in the Treatment of ADHD: What the Evidence Says. Curr Psychiatry Rep, 19: 8.