Anxiety disorders as a collective entity are pervasive and include discrete diagnoses of generalized anxiety disorder (GAD), social phobia (SP), obsessive compulsive disorder (OCD), panic disorder (PD), and post traumatic stress disorder (PTSD) [1
]. Anxiety disorders present with a marked element of psychological tension and distress and are accompanied by a range of somatic symptoms such as palpitations, shortness of breath, dizziness, hyperthermia, and digestive disturbance [1
]. Lifetime prevalence rates of anxiety disorders are approximately 3%–6% for GAD, 4%–6% for SP, 1%–3% for OCD, 1%-2% for PTSD, and 1%–3% for PD [2
There are currently various effective psychological therapies and pharmacological treatments available for anxiety disorders. The recommended first-line treatment strategies for most anxiety disorders include antidepressants and/or cognitive behavioural therapy (CBT) [4
]. In respect to pharmacotherapies, there is a good evidence base for both short-term and long-term treatment with paroxetine (especially for PD), escitalopram, venlafaxine extended release, and duloxetine [5
]. Despite their modest effectiveness (effect size for GAD of 0.38 for selective serotonin reuptake inhibitors: SSRIs) [6
], antidepressants have significant limitations, including a relatively slow onset of action and time to maximal effect, and a number of possible side effects, including initial increase in anxiety in the short-term (often problematic for patient compliance), and sexual side effects, which affect over 50% of users [7
] in the longerterm.
Benzodiazepines have established efficacy for many anxiety disorders [5
] but also numerous limitations. They can be very helpful for ameliorating symptoms rapidly and are usually prescribed for short-term use. However, this recommendation can be very difficult to institute due to potential reliance for symptom relief. Benzodiazepines are no longer recommended beyond short-term use due to potential for abuse, the development of dependence, significant risks when combined with alcohol, and possible long-term cognitive effects [8
]. There have been recent positive randomised controlled trials (RCTs) with pregabalin, however, its indication for GAD in Europe has not yet been replicated by other regulatory authorities [5
]. Psychological techniques are also effective first-line interventions for anxiety [9
]. In particular, there is a body of evidence for CBT that usually involves psychoeducation, relaxation training, cognitive restructuring and behavioural aspects [4
]. Despite effectiveness, some patients are not suited or motivated for face-to-face CBT, access may be an issue, and the cost can be prohibitive [10
Approximately 50%–65% of patients with anxiety disorders benefit from CBT or antidepressants [11
]. However, many patients continue to suffer significant symptoms despite treatment, underlining the need for further options or adjuncts to current conventional treatments. Furthermore, anxiety disorders are often under-treated [13
], motivating patients to seek different treatment approaches such as complementary and alternative medicine (CAM). Non-conventional treatments are commonly used for anxiety, with CAM, lifestyle modifications, and self-help techniques often used in concert with pharmacotherapies and psychological techniques [14
]. Complementary medicines consist of herbal and nutrient products, while complementary therapies include interventions such as acupuncture, naturopathy, chiropractics, and homeopathy [16
]. Self-help techniques include Tai chi, yoga, and meditation, while lifestyle modifications may involve the employment of dietary alteration, exercise, and the minimisation of substances such as alcohol, caffeine, and tobacco. CAM use for people with anxiety disorders is prevalent with a US cross-sectional and longitudinal survey demonstrating 43% of individuals with DSM-IV criteria for GAD, PD, SP, or PTSD use a variety of CAM treatments [17
]. Use of CAM was associated with a diagnosis of GAD, older age, greater education, and having two or more chronic medical conditions.
While previous reviews have explored the use of CAM or self-help techniques in the management of anxiety [14
], to date no review has comprehensively assessed this broad area across all major clinical anxiety disorders to provide an integrated assessment of current evidence. Thus, this narrative paper examines the current evidence base for nonconventional treatments of anxiety disorders, including discussion of their neurobiological underpinnings, and provides considerations for their potential integration into clinical practice.