Ashwagandha: Overview, Efficacy,
Risk
With the use of supplements being a
popular practice, it likely comes as no surprise that a plant-based anti-stress
and anti-anxiety supplement has been advertised extensively. Withania
somnifera, more frequently referred to as ashwagandha, has been touted for its
beneficial capabilities, with significant implications regarding its ability to
reduce stress levels.1 Despite its many claims, however, sufficient
information is questionable as to the benefits it provides. A further look at the
history of its use as well as its evidential efficacy is warranted,
particularly due to the widespread recommendations of its use.
History
Ashwagandha is a plant from which
the root and berries have historically been used to create medicinal compounds.
Utilized by Ayurvedic, Indian and Unani medicine, ashwagandha has been
prescribed for a whole host of physical and mental maladies ranging from
arthritis, tumors and tuberculosis to stress, difficulty thinking and anxiety.1
In a brief review article referencing ashwagandha, one author stated that
the health implications for this plant are extensive, being consistently used
in Indian and Ayurvedic medicine.2 Further the author stated that
particularly noteworthy amongst uses were implications of benefit for tumors,
inflammation, infectious diseases, fevers and inflammatory conditions.2, 3
However, despite the plethora of assumed uses, the author noted that the
traditional use of this plant “may not be supported by scientific studies”.2
In addition to the long list of illnesses ashwagandha is suggested to
treat, it is also commonly referred to as an adaptogen (possessing the ability
to aid the body in the normalization and regulation of systemic stress).1 Ashwagandha
has frequently been used as a naturally-occurring anti-stress and anti-anxiety
agent, which will be the central focus of this paper.1
Efficacy
In a double-blind, randomized,
placebo-controlled study, researchers looked at the effect of ashwagandha
extract capsules (formulated from the roots and leaves) on chronically stressed
humans.5 The 98 subjects who completed the study were divided into
four groups, three with various dosages and frequency of dosages and one
control group.5 Results showed improvement of anxiety ratings in all
of the treatment groups when compared to placebo, thus leading researchers to
conclude that the claims regarding ashwagandha’s anxiolytic effects were
warranted.5 However, it is important to note that not only was the
research performed with the financial support of Natreon Inc., the patent
holder of withania somnifera but several of the researchers were employed or
worked voluntarily at Natreon or
NutraGenesis LLC, a retailer of withania somnifera.5 Therefore, the
results of this study should be accepted cautiously, due to the financial
investment and potential benefit these results may provide the companies
involved.5
Looking at the anxiolytic efficacy
of an ethanolic extract of withania somifera (tablet form), a double-blind, placebo-controlled evaluation was
performed with 39 subjects diagnosed with ICD-10 generalized anxiety disorder,
mixed anxiety and depression, panic disorder, and adjustment disorder with
anxiety.6 Participants were evaluated at two and six weeks using the
Hamilton Anxiety Scale, the Global Rating Scale and the Systematic Assessment
for Treatment Emergent Effects (SAFTEE) symptom checklist.6
Commenting on participant dropout during the study, researchers stated that
upon investigation, drop-outs occurred due to lack of benefit, adverse side
effects, need for increased medication and undisclosed reasons.6
Following a review of results, researchers concluded that a demonstration of
ashwagandha’s anxiolytic effects was evident and proved superior than placebo
at the two-week follow-up and statistically significant at the 6-week
follow-up.6 Once again of note, the research study was supported by
a grant provided by Gufic LTD, Bombay, the manufacturer of the ashwagandha
formulation tested.6 Though this acknowledgement does not infer
automatic inferiority of the study results, it does give rise for additional
caution of study bias.
In a randomized controlled trial,
researchers examined the efficacy of naturopathic care for patients with
anxiety.7 All participants suffered from moderate to severe anxiety
for at least six weeks prior to the beginning of the study.7 Forty-one
subjects received naturopathic care (NC) and forty subjects received
standardized psychotherapy (PT), both for a duration of 12 weeks.7 Subjects
in the NC group received several forms of treatment including dietary
counseling, deep breathing relaxation techniques, a standard multi-vitamin and
ashwagandha (extracted from the root).7 Similarly, the PT group
engaged in several treatments including deep breathing relaxation techniques
and placebo.7 Intended to
measure anxiety, mental health, and overall quality of life, results were evaluated
using the Beck Anxiety Inventory (BAI), the Short Form 36 (SF-36), Fatigue
Symptom Inventory (FSI), and Measure Yourself Medical Outcomes Profile (MY-MOP).7
Participants were observed for at least eight weeks, during which time,
BAI scores decreased by 56.5% in the NC subjects compared to 30.5% in the PT
subjects.7 Further, significant differences presented with the two
groups, with the NC group demonstrating greater clinical benefit in the areas
of mental health, concentration, fatigue, social functioning, vitality, and
overall quality of life.7 Though both groups demonstrated
improvement in levels of anxiety, researchers concluded that the NC group
benefited more from treatment when compared to the PT group.7 One
limitation worth noting is the variety of NC treatments employed makes it
difficult to draw conclusions regarding the efficacy of any one factor.7
Therefore, in regard to the positive effect of ashwagandha based on this
research, it may only prove to be a potential element for benefit with the
necessity of further research. Though results showed positive effect for
naturopathic treatment, including the use of ashwagandha, the products used in
the study were supplied free of charge by the company who makes them, thus
possibly giving rise to caution yet again.7
One prospective, randomized,
double-blind, placebo-controlled study was performed to determine the efficacy
of a high-concentration, full-spectrum extract of ashwagandha root when
administered to adults suffering from stress and anxiety.8 Based
upon the premise that Ayurvedic medicine, animal studies and clinical studies
all point to ashwagandha’s safe and effective role as an adaptogen, researchers
looked at 64 participants with a history of experiencing chronic stress.8 Through
the use of measured serum cortisol levels as well as stress-assessment
questionnaires, researchers evaluated the effect of ashwagandha on the
participants.8 Results indicated significant reduction in symptoms
on all measures in the ashwagandha group when compared to the placebo group.8
Further, serum cortisol levels decreased substantially in the ashwagandha
group when compared to the placebo group.8 Researchers concluded that
the outcomes of this study suggested that administering high concentration,
full-spectrum ashwagandha root had an anti-stress effect with little to no side
effects and an overall positive improvement on self-assessed quality of life.8 Researchers admitted that the study was small
and the duration was limited, thus recommending studies with larger sample
sizes and longer treatment periods are warranted.8
In a
randomized, double-blind, placebo-controlled study, researchers examined the
effect of ashwagandha on generalized anxiety disorder (GAD).9 The study consisted of 86 patients
diagnosed with GAD, divided into two groups.9 The treatment group
received four grams of ashwagandha root in granule form three times a day for
60 days while the placebo group received four grams of placebo for 60 days.9
Researchers measured a variety of symptoms including tension, fear, insomnia,
difficulty with concentration/memory, depressed mood, sensory and muscular
complaints, and anxiety.9 Results
showed that on all measures both groups experienced highly significant
improvement but on all measures except one, there was no significant difference
between the treatment and placebo groups.9 Researchers stated that anxiety
was the only factor that improved in a superior manner with the administration
of ashwagandha compared to the placebo.9 However, researchers commented,
“On the whole, despite having insignificant statistical difference in both the
groups, Group A, Ashwagandha (Withania somnifera) granules, showed a better
percentage improvement than Group B (placebo). Ashwagandha (Withania somnifera)
granules have shown superior results in the management of GAD as compared to placebo
granules. Hence, the alternate hypothesis is accepted i.e. Ashwagandha
(Withania somnifera) is effective in the management of Generalized Anxiety
Disorder”.9
Pratte and colleagues performed a
systematic review of several of the above-mentioned studies and made several
interesting comments regarding the outcomes and validity of the studies.10
Across the five studies fitting inclusion criteria, researchers reported
consistently positive study results regarding the use of ashwagandha to lessen
stress and anxiety.10 However, researchers illuminated multiple
study limitations in all of the reports reviewed including researcher bias,
small sample sizes, short duration of trials and lack of researcher blinding.10
Further, according to Cochrane criteria, none of the studies achieved low
risk-of-bias rating.10 Therefore, researchers concluded that though
the results of the studies showed ashwagandha’s superiority over placebo, the
outcomes must be taken with cautionary optimism.10
Side Effects and Risk
Though ashwagandha has been reported
as a “possibly safe” plant for ingestion, it is important to investigate the
overall side effect profile as well as the potential risk of use.1
Some state that large doses of the plant may produce stomach upset, diarrhea
and vomiting and further, that the long-term safety of its use has not yet been
determined.1 In addition, some caution has been recommended for
those suffering from various diseases, based upon possible risks associated
with interactions of medications or disease progression.1 Others
suggest ashwagandha may lower blood sugar levels or interfere with medications
in diabetic patients, decrease blood pressure in people with hypotension,
irritate the gastrointestinal tract, increase immune system activity in
autoimmune patients, slow down the central nervous system thus causing
complications with anesthesia, and increase thyroid hormone levels in those
suffering from thyroid disorders.1 These potential side effects and
risks present the importance of using ashwagandha with discretion. For the
current analysis, the studies previously reviewed shed further light on the
side effect profile of this so-termed medicinal plant.
When human clinical trials were
reviewed in regard to the anxiolytic effects of plant-based medicines,
researchers concluded that ashwagandha was well tolerated by subjects and did
not produce any heightened levels of adverse effects when compared to placebo.4
Of the 98 subjects who participated
in a double-blind, randomized, placebo-controlled study on the effect of
ashwagandha on chronically stressed humans, researchers reported that adverse
effects were absent in all subjects, including those who dropped out of the
study.5 Researchers clarified further, stating that the lack of
adverse effects was observed regardless of dosage or frequency of administration.5
When an ethanolic extract of
ashwagandha was used in a double-blind, placebo-controlled study involving
patients diagnosed with anxiety disorders, the plant was not only well
tolerated by participants but adverse side effects were comparable to those
demonstrated in participants using placebo.6 Researchers stated a
percentage of subjects dropped out of the study, reportedly due to adverse
effects, yet fewer came from the ashwagandha group when compared to the control
group.6 Further, adverse effects were observed early in the study
and were reportedly easily managed by way of dosage adjustment.6 Of additional importance, though abrupt
withdrawal was initiated at six weeks, no withdrawal symptoms appeared in the
participants, thus leading researchers to state ashwagandha’s superiority to
the conventional anxiolytic drugs such as benzodiazepines, tricyclic
antidepressants, and buspirone which oftentimes have adverse withdrawal
effects.6
In a randomized study performed to
determine the effectiveness of naturopathic care on measures of anxiety
compared to standardized psychotherapy treatment, researchers looked at the
benefit of several treatments including ashwagandha.7 Researchers
did not observe any serious adverse reactions from the dispensation of
ashwagandha.7
When used in a prospective,
randomized, double-blind, placebo-controlled study, high concentrations of
full-spectrum extract of ashwagandha root produced favorable results with few
side effects.8 Follow-up interviews were conducted over the phone on
days 15, 30, and 45 to evaluate treatment compliance as well as evaluation of
any adverse reactions.8
Additional safety and efficacy evaluations were performed on day 60.8
Out of the 61 subjects reviewed, only six adverse events were reported, a
minimal number particularly when compared to the five adverse events reported
in the placebo group.8 Reported side effects were nasal congestion,
constipation, cough/cold, drowsiness and decreased appetite in the treatment
group compared to dry mouth, fatigue, fever, headache, abdominal pain, diarrhea
and tremors in the legs in the control group.8 Researchers further
stated that all adverse events were mild and “no known mechanisms relate these
adverse events to the study drug”.8
Researchers in a randomized,
double-blind, placebo-controlled study examined the effect of ashwagandha on
generalized anxiety disorder (GAD) in 86 patients previously diagnosed with
this disturbance. Outcomes of the study indicated a lack of adverse side
effects for those ingesting ashwagandha over the course of the investigation.9
Conclusions
From the above-reviewed studies, it
appears that ashwagandha may have beneficial potential for aiding in the
reduction of symptoms pertaining to stress and anxiety. It is important to note
that in some studies, though positive benefit was observed, the favorable
outcomes were not deemed statistically significant.
A point worth mentioning is the
fact that despite the varied nature of administration, it did not appear that
the manner in which the plant was distributed (i.e. tablet form, pill form,
granule form), the dosage or the frequency of ingestion significantly influenced
the outcomes of the plant’s efficacy rating. Of significant note is the lack of
reported adverse side effects as well as the lack of negative feedback in
regard to withdrawal symptoms. Though side effects, adverse reactions and
withdrawal symptoms may have been underreported, there did not appear to be
evidence pointing to their frequency or significantly problematic nature. These
factors point to the possible positive nature of ashwagandha in those dealing
with symptoms of anxiety and heightened stress without the added concern of
contracting adverse reactions.
As previously mentioned, limitations
did exist across all of the studies, giving rise to caution when drawing conclusions
yet the preponderance of the evidence points to the prospective but cautionary
use of ashwagandha as an effective way treat symptoms associated with stress
and anxiety. However, it is important to recognize that though the use of
ashwagandha to ameliorate unpleasant symptoms may provide relief, it serves
primarily as a symptom manager. In other words, the underlying cause of the
anxiety and stress does not get addressed at the core if surface symptoms are
simply alleviated. Therefore, if this plant is used to aid in the process of
treatment, it may be advisable to utilize it as a complementary modality rather
than a primary method of therapy.
Clinical Note
Within a practice setting, I would
likely veer away from recommending such a supplement due to the potential for
it becoming a crutch and thus preventing clients from delving into the real
issues at hand. However, I am not sure I would spend a whole lot of time
talking a client out of using such a product if he/she is set on using it,
namely because it does not appear that ashwagandha presents significant risks
or side effects. If a client chose to utilize this supplement as a symptom
reliever, I would be sure to explain the research behind it, my reservations
regarding its use, and ultimately the importance and necessity of the client
making a personal and informed decision about it.
References
3.
Duke
JA. In: CRC Handbook of Medicinal Herbs.
2nd ed. Boca Raton, FL: CRC Press; 2002: 41-42.
4.
Sarris
J, McIntyre E, Camfield DA. Plant-based medicines for anxiety disorders, part
2: a review of clinical studies with supporting preclinical evidence. CNS Drugs. 2013; 27(4): 301-19.
5.
Auddy
B, Hazra J, Mitra A, Abedon B, Ghosal S. A standardized withania somnifera
extract significantly reduces stress-related parameters in chronically stressed
humans: a double-blind, randomized, placebo-controlled study. Journal of the American Nutraceutical
Association. 2008; 11(1): 50-56.
6.
Andrade
C, Aswath A, Chaturvedi SK, Srinivasa M, Raguram R. A double-blind,
placebo-controlled, evaluation of the anxiolytic efficacy of an ethanolic
extract of withania somnifera. Indian Journal of Psychiatry. 2000; 42(3):
295-301.
7.
Cooley
K, Szczurko O, Perri D, et al. Naturopathic care for anxiety: a randomized
controlled trial ISRCTN78958974. PLoS ONE.
2009; 4(8): 1-10.
8.
Chandrasekhar
K, Kapoor J, Anishetty S. A prospective, randomized double-blind,
placebo-controlled study of safety and efficacy of a high-concentration
full-spectrum extract of ashwagandha root in reducing stress and anxiety in
adults. Indian Journal of Psychological
Medicine. 2012; 34(3): 255-262.
9.
Khyati
S, Anup T. A randomized double-blind placebo-controlled study of ashwagandha on
generalized anxiety disorder. International
Ayurvedic Medicine Journal. 2013; 1: 1–7.
10.
Pratte
MA, Nanavati KB, Young V, Morley CP. An Alternative Treatment for Anxiety: A
Systematic Review of Human Trial Results Reported for the Ayurvedic Herb
Ashwagandha (withania somnifera). Journal
of Alternative and Complementary Medicine. 2014; 20(12): 901-908.
