More research needed on OTC products commonly used for anxiety
Writing in the Journal of Mental Health, researchers from University College London recommended evaluating products against or alongside conventional anxiety treatments to better reflect patient choices.
They reported that people often manage their anxiety symptoms themselves using OTC products, including herbal medicines and supplements. However, healthcare professionals and the public find it difficult to compare or understand the evidence for these products, as results are often spread across different academic reviews—with studies using varying dosages.
“The supplement industry should be aware that anxiety is a common reason for taking herbal products and dietary supplements, but many products have a limited evidence base at present,” said lead researcher Rachael Frost.
Lack of information on treatments
An estimated 5.9% of UK adults have Generalized Anxiety Disorder (GAD). In addition to affecting quality of life, anxiety is associated with poorer sleep, increased risk of depression and coronary heart disease, cardiovascular mortality and stroke.
It is also associated with using more complementary treatments, however, National Institute for Health and Care Excellence (NICE) guidelines recommend discouraging OTC preparations because of a lack of evidence supporting safe use.
Despite this, the researchers noted that they are still widely taken. Estimates differ by country, but surveys suggest between 17% and 72.8% of participants have used herbal medicines for anxiety symptoms.
People with anxiety report a lack of information on treatment effectiveness, according to the review, and seek information through the internet or from family and friends, with half not disclosing herbal medicine use to their general practitioner.
An inclusive review
Researchers searched the MEDLINE, EMBASE, PsycInfo, AMED and CENTRAL databases. Instead of looking for names of individual products, the team generated both broad and specific product terms and piloted and refined them in scoping searches.
Eligibility criteria included randomized controlled or crossover trials (RCTs), with any comparator, and oral over-the-counter medicines, herbal products, homeopathic products and dietary supplements used for at least one week.
The term OTC can include a wide range of products—with regulations differing between countries.
For example, kava is available in Australia but not in the UK. With this in mind, researchers included OTC products without practitioner input, irrespective of their status in the UK, after discussion with clinical and PPI team members. They said this allowed the review to be as inclusive as possible, as a wider range of products can often be purchased online.
The research team identified 69 RCTs and nine protocols for ongoing studies testing 43 OTC products on people with anxiety, mainly focusing on kava, lavender, saffron, probiotics, Galphimia glauca and valerian. Trials on CBD products for anxiety are increasing, which likely reflects increasing public interest.
The researchers reported that “herbal products are more likely to be promising anxiety treatments than dietary supplements, which showed a lower volume of evidence and little promise at present in our review.”
They added: “Whilst most herbal product trials reported positive results, many of these need to be replicated, particularly for commonly used products such as chamomile, lemon balm and St John’s Wort, alone or in combination.
They concluded this should include different doses to evaluate the use of products against or alongside conventional anxiety treatments, such as antidepressants and cognitive behavioral therapy, to better inform patient decision-making.
“The supplement industry should be reassured that most products have a good safety profile, but few trials evaluated their effects alongside antidepressants, which supplements are often taken alongside,” Frost said.
Source: Journal of Mental Health
doi: 10.1080/09638237.2024.2408231
"What over the counter (OTC) products have been evaluated for anxiety in adults aged 18–60? A scoping review"
Authors: Rachael Frost et al.
