Anxiety disorders are defined by the 5th edition of the American Psychological Association (APA)’s Diagnostic And Statistical Manual (DSM-5) as a group of disorders "that share features of excessive fear and anxiety and related emotional disturbances".^[1] Generalized anxiety disorder (GAD) is an anxiety disorder characterized by excessive, frequent, hard-to-control anxiety and worries about everyday activities and events over a period of at least six months. The anxiety and worries cause distress or difficulty functioning and are accompanied by several additional symptoms, including restlessness, fatigue, concentration difficulties, irritability, muscle tension, and/or sleep disturbances.^[1]

Per the American Psychological Association (APA), the symptoms of GAD include anxiety and worries, distress, difficulty functioning, restlessness, fatigue, difficulty concentrating, irritability, tension, and/or sleep disturbances.^[1]

Diagnosing GAD is done through a psychological evaluation performed by a clinician, after ruling out other potential causes of symptoms such as medication, drugs, other anxiety disorders, or other medical conditions.^[2] The psychological evaluation is typically based on diagnostic criteria set by a publication such as the American Psychological Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM) or the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems (ICD). In 2022, 5.2% of Canadians 15 years and older met the diagnostic criteria for GAD.^[3] The diagnostic criteria for GAD in the DSM 5th edition are:

• Excessive, difficult-to control, frequent anxiety and worry about multiple different events or activities; and
• the anxiety/worries cause distress or difficulty functioning; and
• the anxiety/worries are associated with at least three of the following additional symptoms:
  • restlessness
  • fatigue
  • difficulty concentrating
  • irritability
  • muscle tension
  • sleep disturbances.

To be diagnosed as GAD, the anxiety and worries must have happened more days than not for at least six months and have been about multiple different events and activities. Additionally, the diagnosis of GAD can only be made if the symptoms can't be better explained by the effects of a medication or drug, by another medical condition, or by another mental disorder.^[1]

A supplement that helps a situationally stressed person with transient anxiety won’t necessarily be effective for a person with generalized anxiety disorder (GAD). The best evidence for relieving anxiety symptoms in the context of GAD comes from trials whose participants have all been diagnosed with GAD. Although many supplements have been studied for anxiety symptoms, relatively few trials have been specifically in people with GAD. Supplements that have demonstrated promise in preliminary research include lavender oil, passionflower, ashwagandha, saffron, and ginkgo biloba.

• A 2010 randomized controlled trial (RCT) in people with GAD found daily lavender oil capsules to be as effective as a benzodiazepine for GAD.^[4]
• In a small 2001 RCT, passionflower extract was as effective for treating the symptoms of GAD as oxazepam (a benzodiazapine).^[5] More recently, in a 2016 RCT of passionflower extract as an add-on to sertraline (an antidepressant) in people with GAD, self-rated anxiety was lower after a month of passionflower than a month of a placebo.^[6]
• In a small 2013 RCT, people with GAD who took ashwagandha powder for two months had noticeably lower “anxious mood” scores compared to people who took a placebo powder, although there was no difference in the other symptoms.^[7]
• In a small 2017 RCT in people with GAD, the participants who took saffron extract as an add-on to sertraline therapy for 6 weeks had lower anxiety scores than the participants who took a placebo add-on.^[8]
• In a small 2007 4-week study, the anxiety scores of participants were reduced more with ginkgo biloba extract than with a placebo. However, while the majority of the participants in this study were people with GAD, about one-quarter of the participants were people with adjustment disorder with anxious mood instead.^[9]
• In a small 2002 pilot study comparing valerian extract to diazepam (a benzodiazepine) and a placebo in people with GAD, valerian didn’t reduce overall anxiety scores as much as the placebo did.PMD:12410546
• Although kava is generally effective for treating anxiety symptoms, in a 2022 review of studies, it was not as effective in people with GAD.^[10]

Because of the small size of these trials, more research is necessary to confirm these findings.