The primary outcome of this randomized double-blind placebo-controlled study was to investigate the effect of Shoden 60 mg and 120 mg (35% withanolide glycosides (WG)) in subjects with generalized anxiety disorder with HAMA. Both AE60 and AE120 groups significantly reduced their total score of HAMA by 59% (p < 0.0001). A nonparametric longitudinal factorial analysis (nparLFD) on the interaction of time and IP was highly significant (p < 0.0001) indicating that the decrease in anxiety scores was definitely due to the intervention. The relative treatment effects (RTE) show that the outcome variable (HAMA score) was significantly decreased compared to the placebo. The plot of RTE shows that the lines diverge early and remain separated, indicating that the IP effect was immediate and sustained. The lines of AE60 and AE120 converge over time, indicating no apparent intervention difference between the two, based on HAM-A scores.
Adrenal glands, in response to stress, produce cortisol, and prolonged exposure to high levels of cortisol can have a significant effect on mental and physical health, contributing to the symptoms of GAD. Studies have shown that individuals with high stress and anxiety have higher cortisol levels than normal individuals, particularly in response to stressors, and have been associated with increased anxiety symptoms and decreased quality of life 23,24. The HPA axis has an inbuilt cortisol negative feedback system, but chronically elevated levels can lead to a decrease in the sensitivity of the HPA axis, which can result in a blunted response to stressors. Cortisol has been shown to interact with neurotransmitters involved in regulating anxiety, such as serotonin and gamma-aminobutyric acid (GABA). It decreases the availability of serotonin and increases the activity of the enzyme responsible for breaking down GABA. These interactions may further contribute to the development and maintenance of anxiety disorders. High cortisol levels have been shown to negatively affect the hippocampus, which is a region of the brain involved in memory and emotion regulation, and impairing its functioning. This may contribute to the cognitive deficits and emotional dysregulation observed in individuals with high stress and elevated cortisol levels.
In this study, there was a significant reduction in serum morning cortisol as a measure of stress in the AE60 and AE120 groups by 66% and 67%, whereas the placebo had only a 2.22% change. The significant interaction between IP and time (p < 0.0001) indicates that the change observed in all five timepoints was due to the effect of AE60 and AE120. Research suggests that withanolide glycosides (WG) may have a modulating effect on cortisol levels.
Ashwagandha has been shown to enhance GABAergic activity and modulate neurotransmitters such as serotonin and dopamine, which may help to alleviate anxiety symptoms. High stress levels and negative thoughts correlate negatively with Serotonin Receptor 5HT1a, and perception of stress is a predictive model of the expression of 5HT1a 25. In the present study, the perceived stress scale score was significantly decreased by 53% in the AE60 group and 62% in the AE120 group. The placebo response showed only about a 5% decrease. The IP (p < 0.0001), time (p < 0.0001), and interaction between IP and time (p < 0.0001) all had a statistically significant effect on the outcome variable of perceived stress.
Elevated levels of cortisol can have an inhibitory action on testosterone production leading to decreased sex drive, muscle mass, and bone density, in turn affecting the quality of life 26. Even though testosterone level was not an inclusion criterion in this study, the baseline mean values (3.08 to 3.21 ng/mL) were at the lower end of normal range (3-10ng/mL). In this study, serum total testosterone had a 22% and 33% increase in AE60 and AE120, respectively, whereas in the placebo, there was only a 4% increase in males. There was no clinically significant increase in female testosterone. Another study conducted by Adrian et al, in 2019, involving aging, overweight males, with a 16-week regimen of Shoden delivering 21mg withanolide glycosides daily resulted in a notable 14.7% increase in testosterone levels. 27. This increase in male testosterone levels might be related to the cortisol lowering effect of ashwagandha.
A 2021 study on the effect of the comedication of ashwagandha root extract with SSRIs on GAD found that after 6 weeks of intake of 1g per day of ashwagandha extract, HAMA scores decreased from 29.11 at baseline to 15.27, representing a 47.6% reduction 28. In comparison, our study examined the effects of a standardised extract of 35% WG in 60mg and 120mg AE with naïve GAD subjects. It was found that after 60 days, subjects taking 60mg/day of AE had HAMA scores decrease from 24.25 to 9.95, a 59.1% decrease, while those on 120mg/day had decreased from 23.5 to 9.65, representing 58.9% reduction. Although the study by Fuladi et al. used a higher dose of whole root extract, our study demonstrated that lower doses can bring about even greater anxiety reductions of 59% (for both AE60 and AE120) which can be attributed to the increase in the concentration of withanolide glycosides.
A 60-day study of the anxiolytic effect of 240 mg ashwagandha with 35% WG reported a 41% reduction in HAMA 15. The inclusion criteria in the Lopresti study was a HAMA score of 6–17 and hence the mean baseline value was 10.27 which decreased to 6.07. In the present study the inclusion criteria were specifically for GAD with HAMA score of greater than 20 with a mean baseline of 24.25 and 23.5 for AE60 and AE120 respectively.
A study by Chandrashekar et al examining the effect of a 300 mg twice a day of high-concentration full-spectrum ashwagandha root extract (5% WG) for 60days on stress and anxiety found that there was a 44% change in the PSS score 29. It was noted that there was a 53% change in AE60 and 62% change in AE120 in the present study for the PSS stress score.
The CGI which is a clinician’s view of the subjects overall functioning before and after the intervention is well correlated with HAMA. In the present study the investigators were able to see 72% and 68% decrease in the severity of anxiety for AE60 and AE120 respectively while placebo had a 21% change. The analysis of interaction between IP and time was highly significant (p < 0.0001). This implies that the benefit seen is actually due to the effect of the intervention rather than a normal reduction of symptoms with time.
Anxiety and depression are highly comorbid. NESDA study reported that of depressive people 67% had a current and 75% had a lifetime comorbid anxiety disorder. Without controlling for depression, it can be difficult to determine if changes in anxiety symptoms are due to the treatment or just reflecting changes in depressed mood. Depression can influence anxiety ratings and reports. Feeling depressed can exacerbate negative perceptions and worries, causing anxiety scores and reports to increase 30. Conversely, reducing depression may make anxiety feel more tolerable, leading to lower anxiety reports even if actual anxiety symptoms do not change. Many of the studies on anxiety and stress did not control for and may have included depression along with anxiety which may influence the results. In this study we have excluded depressed subjects with a MADRS total score greater than 12 and with apparent and reported sadness ≥ 2, Item 10 (suicidal thoughts) score > 1 or suicide attempt in the 6 months prior to screening. Additionally, we have excluded night shift workers who have a disrupted circadian rhythm due to their sleep schedules. This can alter the normal diurnal pattern of cortisol secretion, including morning cortisol levels. This disruption could obscure the effects of ashwagandha or produce misleading results. Many studies could produce misleading results when not accounting for this. Limitations of the present study are its small sample size, lack of a 1:1 gender ratio, and shorter duration. These limitations can be addressed in future research through placebo-controlled studies of longer duration, larger size, broader populations, and careful control of confounders that will help expand the evidence base and enhance the validity and applicability of findings.