Effects of Silexan on the serotonin-1A receptor and microstructure of the human brain: a randomized, placebo-controlled, double-blind, cross-over study with molecular and structural neuroimaging

Silexan in anxiety, depression, and related disorders: pharmacological background and clinical data

We present a narrative review of clinical trials investigating the anxiolytic and antidepressant effects of silexan, an active substance derived from lavender oil and summarize nonclinical findings from pharmacological studies supporting its therapeutic use. Six studies investigated the efficacy of the lavender oil in patients with subthreshold and generalized anxiety disorders as well as in mixed anxiety and depressive disorder (MADD). Furthermore, we present data indicating that silexan may influence sleep quality as well as anxiety or depressive disorders in individuals with post-COVID-19. Silexan taken orally at a daily dose of 80 mg for 10 weeks was significantly superior to placebo in reducing psychic and somatic symptoms of anxiety and was as effective as 0.5 mg/d lorazepam and 20 mg/d paroxetine. In patients with mild or moderate major depression, silexan was superior to placebo and comparably effective to 50 mg/d sertraline. Significant antidepressant effects were also observed in MADD and depression co-morbid with anxiety. The herbal product had a beneficial effect on activities of daily living and health-related quality of life. Adverse events associated with silexan in clinical trials were limited to eructation and mild, transient gastrointestinal complaints. The herbal product was not associated with drug interactions, sedation, sleep disturbance, dependence and abuse potential, sexual dysfunction, weight gain or withdrawal symptoms. Silexan was therefore safe and effective in subthreshold and syndromal anxiety disorders and in major depression.

The efficacy of oral Lavandula angustifolia Mill. essential oil on menopausal symptoms, serum lipid profile, and cortisol concentration in postmenopausal women: A triple-blind, randomized, controlled trial

OBJECTIVE

To determine the effect of oral Lavandula angustifolia Mill. essential oil (LEO) on menopausal symptoms, serum cortisol level, and lipid profile in postmenopausal women.

METHODS

This was a triple-blind parallel-armed randomized trial. Seventy-two postmenopausal women aged 50-65 years referring to healthcare centers in Tabriz, Iran with a score of 15-42 on the Green scale were included from May 10, 2022 to May 22, 2023. The participants were randomly assigned to two groups with a 1:1 ratio and using four and six blocks. One group received LEO soft gel 80 mg per day, and another group received a similar placebo for 60 days. A demographic questionnaire and a Greene menopause symptom scale were used for data collection. The lipid profile (total cholesterol, triglyceride, LDL, HDL) and the serum levels of cortisol were measured using biochemical methods. Chi-square, Fisher's exact tests, Independent samples t-test, Analysis of Covariance (ANCOVA), Repeated measure ANOVA, and Paired sample t-test were utilized for analyses. A p-value less than 0.05 was considered statistically significant.

RESULTS

The demographic and personal characteristics of the participants were similar. After two months of intervention, all symptoms in psychological, physical, vasomotor, anxiety, depression, and sexual dysfunction domains were significantly relieved (decreased) among both groups (p < 0.003), except for sexual dysfunction, the reduction of which was not significant in the placebo group (p = 0.317). The mean (SD) total score of menopausal symptoms reduced from 27.4 (6.3) at baseline to 17.7 (4.9) at the end of the study in the LEO group (p < 0.001). It also decreased from 27.4 (7.1) to 17.6 (5.1) in the placebo group (p < 0.001). However, between-group analyses revealed that this reduction was significantly greater in the LEO group compared to the placebo group only in the sexual dysfunction (Mean (SD): 1.3 (0.6) vs. 1.0 (0.5); adjusted mean difference (95% confidence interval); p: - 0.35 (-0.67 to -0.02); 0.039). No significant within-group changes or between-group differences were observed (p > 0.05) in terms of studied serum markers.

CONCLUSION

The oral LEO exhibited a significant enhancement in sexual dysfunction among postmenopausal women. Therefore, it can be used alongside other therapies to improve sexual dysfunction during menopause. LEO did not affect lipid profile and serum cortisol level in this study.

Lavender oil preparation Silexan is effective in mild-to-moderate major depression: a randomized, placebo- and reference-controlled trial

Anxiety and depressive disorders have overlapping symptoms and share common neurobiological pathways. Antidepressant drugs have been demonstrated to be efficacious in anxiety as well. Vice versa, it may also be promising to investigate the efficacy of anxiolytic drugs such as silexan in major depressive disorder (MDD). Patients with a mild or moderate, single or recurrent episode of MDD and a total score of 19-34 points on the Montgomery Åsberg Depression Rating Scale (MADRS) were randomized to receive 1 × 80 mg/d silexan, 1 × 50 mg/d sertraline, or placebo double-blind, double-dummy for 56 days. The primary outcome measure was the MADRS total score change between baseline and treatment end. Treatment groups were compared using a treatment policy estimand. 498 subjects (silexan 170, sertraline 171, placebo 157) were treated and analyzed. After 8 weeks, silexan and sertraline were superior to placebo for MADRS total score reduction, with absolute differences to placebo of 2.17 (95% confidence interval: 0.58; 3.76) points and 2.59 (1.02; 4.17) points, respectively (p < 0.01). Moreover, silexan was superior to placebo for alleviation of functional impairment according to the Sheehan Disability Scale with a difference of 2.40 (1.04; 3.76) points (p < 0.001). Both treatments were well tolerated; eructation was the most frequent adverse effect of silexan. The study confirms the antidepressant efficacy of silexan in mild or moderate MDD, including significant improvements in the subjects' functional capacity. The results for sertraline confirm the assay sensitivity of the trial. Both drugs were well tolerated.Trial registrationEudraCT2020-000688-22 first entered on 12/08/2020.

Efficacy of Silexan in patients with anxiety disorders: a meta-analysis of randomized, placebo-controlled trials

INTRODUCTION

We report on a meta-analysis of Silexan, a proprietary active substance produced from Lavandula angustifolia, in subthreshold anxiety, mixed anxiety and depressive disorder (MADD), and generalized anxiety disorder (GAD).

METHODS

The present analyses are based on all currently completed 5 double-blind, randomized, placebo-controlled trials investigating Silexan in adult out-patients who received Silexan 1 × 80 mg/day or placebo for ten weeks according to random assignment (n = 1213). Efficacy was assessed based on the Hamilton Anxiety Rating Scale (HAMA), several anxiety self-rating scales, the Clinical Global Impression (CGI) scale, and the Short Form-36 (SF-36) health status questionnaire.

RESULTS

After ten weeks' treatment, Silexan was significantly superior to placebo in reducing the HAMA total score (including the psychic and somatic anxiety sub-scores) and self-rated anxiety. Based on a ≥ 50% HAMA total score reduction, the responder rate ratio was 1.34 favoring Silexan, and the rate ratio of subjects much or very much improved according to the CGI was 1.51. Silexan was also significantly superior in improving the physical and mental health summary scores of the SF-36. There were no significant between-group differences concerning the occurrence of adverse events (AEs), serious AEs, and premature withdrawal due to AEs.

CONCLUSIONS

This meta-analysis demonstrates that Silexan exerts significant anxiolytic effects in subthreshold anxiety, GAD and MADD that were consistently reflected in investigator ratings and patient-reported outcomes, including improvement of health-related life-quality, while showing favorable tolerability and safety.

Psychiatric manifestations of post-COVID-19 syndrome: the potential benefit of Silexan

Objective: Psychiatric symptoms are common and bothersome in individuals with post-COVID-19 syndrome. Because they are often mixed and subthreshold, established treatment regimens cannot be applied. There is an urgent need to identify therapeutics for affected patients. Silexan, a proprietary essential oil from Lavandula angustifolia, has demonstrated efficacy against anxiety, comorbid symptoms, and subthreshold and mixed syndromes. The aim of the current narrative review is to examine the therapeutic potential of Silexan for psychiatric manifestations in patients with post-COVID-19 syndrome.Methods: We reviewed clinical evidence regarding the efficacy of Silexan and first clinical experience in patients with psychiatric symptoms attributable to the post-COVID-19 syndrome. Furthermore, we discussed potential modes of action based on nonclinical data.Results: Silexan has demonstrated therapeutic efficacy for the treatment of generalised anxiety disorder; subsyndromal anxiety disorders; comorbid depressive, somatic, and sleep disturbance symptoms; and mixed anxiety and depression. Emerging clinical experience also suggests the effectiveness and tolerability of Silexan for patients with post-COVID-19 syndrome. This can be explained by the fact that the therapeutic profile of Silexan overlaps with the spectrum of psychiatric symptoms in such patients.Conclusion: Preliminary findings indicate a promising potential of Silexan for the treatment of psychiatric manifestations in patients with post-COVID-19 syndrome.Key pointsAnxiety and mixed neuropsychiatric manifestations are commonly observed in patients with post-COVID-19 syndrome.Silexan has anxiolytic properties and can alleviate comorbid depressive, somatic, and sleep impairment symptoms.Silexan exhibits several biological mechanisms, such as neurotrophic and anti-inflammatory properties, which have the potential to positively impact post-COVID-19 disease.Silexan has a favourable safety profile and high acceptance among patients.Emerging data suggest that Silexan can alleviate neuropsychiatric symptoms in patients with post-COVID-19 syndrome.Silexan should be considered as a therapeutic in patients with psychiatric manifestations of post-COVID-19 syndrome.

Aromatherapy for the brain: Lavender's healing effect on epilepsy, depression, anxiety, migraine, and Alzheimer's disease: A review article

Neurological diseases affect the nervous system, including the brain, spinal cord, cranial nerves, nerve roots, autonomic nervous system, neuromuscular junctions, and muscles. Herbal medicine has long been used to cure these diseases. One of these plants is lavender, which is composed of various compounds, including terpenes, such as linalool, limonene, triterpenes, linalyl acetate, alcohols, ketones, polyphenols, coumarins, cineole, and flavonoids. In this review, the literature was searched using scientific search engines and databases (Google Scholar, Science Direct, Scopus, and PubMed) for papers published between 1982 and 2020 via keywords, including review, lavender, and neurological disorders. This plant exerts its healing effect on many diseases, such as anxiety and depression through an inhibitory effect on GABA. The anti-inflammatory effects of this plant have also been documented. It improves depression by regulating glutamate receptors and inhibiting calcium channels and serotonergic factors, such as SERT. Its antiepileptic mechanism is due to an increase in the inhibitory effect of GABA and potassium current and a decrease in sodium current. Therefore, many vegetable oils are also used in herbal medicine. In this review, the healing effect of lavender on several neurological disorders, including epilepsy, depression, anxiety, migraine, and Alzheimer's disease was investigated. All findings strongly support the traditional uses of lavender. More clinical studies are needed to investigate the effect of the plants' pharmacological active constituents on the treatment of life-threatening diseases in humans. The limitations of this study are the low quality and the limited number of clinical studies. Different administration methods of lavender are one of the limitations of this review.

The Effects of Essential Oils on the Nervous System: A Scoping Review

Essential oils are a mixture of natural aromatic volatile oils extracted from plants. The use of essential oils is ancient, and has prevailed in different cultures around the world, such as those of the Egyptians, Greeks, Persians, and Chinese. Today, essential oils are used in traditional and complimentary medicines, aromatherapy, massage therapies, cosmetics, perfumes and food industries. The screening effect of essential oils has been studied worldwide. They demonstrate a range of biological activities, such as antiparasitic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anticancer, antiaging, and neuroprotective properties. In this scoping review, we provide a 10-year updated comprehensive assessment of volatile oils and their effects on the nervous system. MEDLINE, Scopus, and Google Scholar were systematically and strategically searched for original studies investigating these effects from 2012 to 2022. Approximately seventy studies were selected as included studies. Among these studies, several outcomes were reported, including antistress, antianxiety, analgesic, cognitive, and autonomic effects. Some essential oils showed developmental benefits, with the potential to induce neurite outgrowth. The neurotransmitter receptor level can also be modified by essential oil application. Physiological and pathophysiological outcome measures were reported. For physiological outcomes, arousal, cognitive performance, circadian eating behavior, emotional modulation, consumer acceptance, preferences, and willingness to buy were investigated. For pathophysiological conditions, pain, depression, anxiety, stress, sleep disorder, mental fatigue, agitated behavior, and quality of life were measured. In conclusion, essential oils showed promising effects on the nervous system, which can be further applied to their use in functional foods, drinks, and alternative therapy.

Lavandula x intermedia-A Bastard Lavender or a Plant of Many Values? Part II. Biological Activities and Applications of Lavandin

This review article is the second in a series aimed at providing an in-depth overview of Lavandula x intermedia (lavandin). In part I, the biology and chemistry of lavandin were addressed. In part II, the focus is on the functional properties of lavandin and its applications in industry and daily life. While reviewing the biological properties, only original research articles employing lavandin were considered. Lavandin essential oil has been found to have antioxidant and biocidal activity (antimicrobial, nematicidal, antiprotozoal, insecticidal, and allelopathic), as well as other potential therapeutic effects such as anxiolytic, neuroprotective, improving sleep quality, antithrombotic, anti-inflammatory, and analgesic. Other lavandin preparations have been investigated to a much lesser extent. The research is either limited or inconsistent across all studies, and further evidence is needed to support these properties. Unlike its parent species-Lavandula angustifolia (LA)-lavandin essential oil is not officially recognized as a medicinal raw material in European Pharmacopeia. However, whenever compared to LA in shared studies, it has shown similar effects (or even more pronounced in the case of biocidal activities). This suggests that lavandin has similar potential for use in medicine.

Efficacy and tolerability of Lavandula angustifolia in treating patients with the diagnosis of depression: a systematic review of randomized controlled trials

Pharmacotherapy is the conventional treatment for depression, with only half of the patients responding to the first trial of monotherapy with first-line medicines. One way to overcome this resistance is to use complementary and alternative medicine. The antidepressant effects of Lavandula angustifolia, which is commonly called lavender, have been investigated in previous studies. This study aims to provide the first systematic review of lavender in treating patients with depression diagnosis. ISI Web of Science, Scopus, PubMed, Embase, PsycINFO, Google Scholar, and three trial registries were searched until May 2020 to find randomized controlled trials on lavender for depressed patients. The primary outcome was difference between the intervention and control groups in changing depression scores from baseline to endpoint. The included studies were assessed for effect size and methodological quality. Seven clinical trials were identified, in which 852 patients were studied. In six trials, the effectiveness of lavender in treating depression was reported, as being more pronounced adjunct to a typical antidepressant in one study. Significant reported side effects include headaches and eructation. Lavender is beneficial, tolerable, and safe in treating depression. Despite obtaining promising results, they are not enough to recommend prescribing lavender to depressed patients. Further high-quality, large-scale studies for rectifying the shortcomings of existing studies are recommended.

Effects of bilateral sequential theta-burst stimulation on 5-HT1A receptors in the dorsolateral prefrontal cortex in treatment-resistant depression: a proof-of-concept trial

Theta-burst stimulation (TBS) represents a brain stimulation technique effective for treatment-resistant depression (TRD) as underlined by meta-analyses. While the methodology undergoes constant refinement, bilateral stimulation of the dorsolateral prefrontal cortex (DLPFC) appears promising to restore left DLPFC hypoactivity and right hyperactivity found in depression. The post-synaptic inhibitory serotonin-1A (5-HT1A) receptor, also occurring in the DLPFC, might be involved in this mechanism of action. To test this hypothesis, we performed PET-imaging using the tracer [carbonyl-11C]WAY-100635 including arterial blood sampling before and after a three-week treatment with TBS in 11 TRD patients compared to sham stimulation (n = 8 and n = 3, respectively). Treatment groups were randomly assigned, and TBS protocol consisted of excitatory intermittent TBS to the left and inhibitory continuous TBS to the right DLPFC. A linear mixed model including group, hemisphere, time, and Hamilton Rating Scale for Depression (HAMD) score revealed a 3-way interaction effect of group, time, and HAMD on specific distribution volume (VS) of 5-HT1A receptor. While post-hoc comparisons showed no significant changes of 5-HT1A receptor VS in either group, higher 5-HT1A receptor VS after treatment correlated with greater difference in HAMD (r = -0.62). The results of this proof-of-concept trial hint towards potential effects of TBS on the distribution of the 5-HT1A receptor. Due to the small sample size, all results must, however, be regarded with caution.

Beneficial effects of Silexan on co-occurring depressive symptoms in patients with subthreshold anxiety and anxiety disorders: randomized, placebo-controlled trials revisited

Silexan is a proprietary active substance produced from Lavandula angustifolia, with proven anxiolytic efficacy in subthreshold and generalized anxiety disorder as well as in mixed anxiety and depressive disorder with beneficial impact on anxiety-related sleep disturbances. The pharmacological profile and clinical observations suggest that Silexan may also have an antidepressant effect. To investigate the effect of Silexan on co-occurring depressive symptoms, we present a meta-analysis of the five placebo-controlled clinical trials hitherto performed with Silexan in subthreshold anxiety (n = 3) and anxiety disorders (n = 2). Patients of all trials received Silexan 1 × 80 mg/day or placebo for 10 weeks according to random assignment. Assessment of the antidepressant effect was based on item 'depressed mood' from the Hamilton Anxiety Rating Scale (HAMA) administered in all trials and on the total scores of the Montgomery Åsberg Depression Rating Scale (MADRS) or the Hamilton Depression Rating Scale (HAMD) used in three trials. After 10-week treatment, patients receiving Silexan showed significantly more pronounced score reduction for HAMA item 'depressed mood' than those in the placebo group (p = 0.01). Significant superiority of Silexan over placebo could also be shown for mean MADRS or HAMD total score reduction (three studies; p < 0.01). Silexan-treated patients with more severe depressive symptoms at baseline showed more pronounced improvements than those with milder symptoms. Our meta-analysis clearly shows that Silexan has a beneficial effect on co-occurring depressive symptoms in patients with subthreshold anxiety and anxiety disorders and may, hence, lead to important therapeutic implications for depressive disorders.

Effect of anxiolytic drug silexan on sleep - a narrative review

OBJECTIVES

Silexan is an orally administered, proprietary essential oil from Lavandula angustifolia with significant anxiolytic and sleep improving properties. Here we present a narrative review that provides an overview of the available evidence of the effects of silexan on sleep.

METHODS

We start with a summary of the pharmacological background and continue with presenting sleep-related results from controlled clinical trials with silexan. Then we report on a meta-analysis of item 'insomnia' from the Hamilton Anxiety Scale, which includes data from all randomised, placebo-controlled clinical trials with silexan in which the scale was administered. Finally, we summarise the results of a mediation analysis that was performed to elucidate the pathway of the effect of silexan on sleep.

RESULTS

In randomised, placebo-controlled trials in patients suffering from anxiety disorders silexan had a significant anxiolytic effect and improved sleep along with recovery from anxiety. Mediation analysis demonstrates that more than 98% of the effect of silexan on sleep was mediated by its anxiolytic effect while the direct effect on sleep was marginal.

CONCLUSIONS

Silexan improves sleep as a result of its anxiolytic effect.

Essential Oils as Multicomponent Mixtures and Their Potential for Human Health and Well-Being

Essential oils (EOs) and their individual volatile organic constituents have been an inherent part of our civilization for thousands of years. They are widely used as fragrances in perfumes and cosmetics and contribute to a healthy diet, but also act as active ingredients of pharmaceutical products. Their antibacterial, antiviral, and anti-inflammatory properties have qualified EOs early on for both, the causal and symptomatic therapy of a number of diseases, but also for prevention. Obtained from natural, mostly plant materials, EOs constitute a typical example of a multicomponent mixture (more than one constituent substances, MOCS) with up to several hundreds of individual compounds, which in a sophisticated composition make up the property of a particular complete EO. The integrative use of EOs as MOCS will play a major role in human and veterinary medicine now and in the future and is already widely used in some cases, e.g., in aromatherapy for the treatment of psychosomatic complaints, for inhalation in the treatment of respiratory diseases, or topically administered to manage adverse skin diseases. The diversity of molecules with different functionalities exhibits a broad range of multiple physical and chemical properties, which are the base of their multi-target activity as opposed to single isolated compounds. Whether and how such a broad-spectrum effect is reflected in natural mixtures and which kind of pharmacological potential they provide will be considered in the context of ONE Health in more detail in this review.

Impact of Lavender on Pain and Anxiety Levels Associated With Spine Procedures

Background: To reduce pain and anxiety associated with interventional pain procedures, sedation is often used, with benzodiazepines, opioids, and propofol the most commonly used classes of drugs for sedation. However, patient coherence and ability to communicate procedural pain and abnormal sensations help prevent adverse outcomes. Therefore, discovering alternative therapies to mitigate the anxiety and pain associated with these procedures and to minimize risk is important. The aim of our study was to investigate whether lavender has an effect on pain and anxiety associated with lumbar epidural steroid injections and lumbar medial branch blocks.

Methods: In this randomized controlled study, 54 subjects were randomly assigned to 1 of 3 intervention groups, and 46 patients were included in the final analysis: experimental lavender group (n=17), control almond oil group (n=15), and placebo sterile water group (n=14). Patients wore a mask infused with either lavender, almond oil, or water for 5 minutes prior to and during their procedure. Patients rated their anxiety using the State-Trait Anxiety Inventory prior to and after the procedure based on how they felt during the procedure. Patients rated their pain according to the numerical rating scale. Outcome measures were a comparison of pain among the 3 groups and a comparison of the change in anxiety before and after the procedure among the 3 groups.

Results: The lavender group demonstrated the highest mean change in anxiety scores (9.9) compared to almond oil (5.3) and water (3.6) preprocedurally vs postprocedurally. The lavender group also reported the lowest mean pain level (3.8) compared to almond oil (5.6) and water (5.6). However, none of the differences between groups showed statistical significance at the P<0.05 level.

Conclusion: Lavender may have a clinically beneficial effect on anxiety levels and pain reduction.

Essential oil therapy for the short-term treatment of behavioral and psychological symptoms of dementia: a monocentric randomized pilot study

BACKGROUND

The behavioral and psychological symptoms of dementia (BPSD) can be severely distressing for both patients and caregivers.

AIMS

This study assessed the efficacy of environmental diffusion essential oil therapy (EOT) combined with psychotropic drug therapy (group A) in BPSD management, compared with psychotropic drug therapy alone (group B). The stress responses of attending caregivers were also assessed.

METHODS

Thirty-two patients with dementia and BPSD were enrolled. The presence and severity of BPSD were assessed using the Italian version of the NPI-NH scale, which also measures the stress felt by professional caregivers. Global geriatric evaluations were performed to rule out acute diseases that could contribute to delirium and worsen patients' mental status.

RESULTS

Following treatment, the average NPI-NH value was significantly reduced in group A compared with group B (p < 0.001). Caregiver distress was also significantly reduced in group A (p < 0.01).

DISCUSSION

This pilot study showed that BPSD were better treated using EOT combined with standard pharmacological treatment, compared with standard pharmacological treatment alone. No adverse effects of EOT were observed. Reductions in caregiver distress could be due either to reductions in BPSD severity and frequency resulting in decreased caregiver burden, and/or the emotional benefit for caregivers of exposure to essential oils.

CONCLUSIONS

This study supports the combined use of EOT and psychotropic drugs in the treatment of BPSD. Essential oils may improve the wellbeing of both patients and caregivers, without adverse effects. Additionally, EOT is easy to administer by environmental diffusion.

Therapeutic effects of Silexan on somatic symptoms and physical health in patients with anxiety disorders: A meta-analysis

A meta-analysis was performed to examine therapeutic effects of Silexan on somatic symptoms, including insomnia/fatigue, and physical health in patients with anxiety disorders. Five randomized, placebo-controlled trials were included in this analysis: The efficacy of Silexan (80 mg/day) was investigated in patients with subthreshold anxiety disorders (three trials) and in patients with generalized anxiety disorder (two trials). Silexan was superior to placebo in terms of the mean change from baseline in the Hamilton Anxiety Rating Scale (HAMA) subscore somatic anxiety at week 10 with a standardized mean difference of -0.31 [95% Cl: -0.52 to -0.10, p = .004]. Treatment effects of silexan on somatic anxiety were independent of gender and age. Statistically significant differences were also shown for single HAMA items somatic muscular, cardiovascular, respiratory, and genitourinary symptoms, indicating clinical relevance with small to medium effects of Silexan. Similar clinically meaningful effects of Silexan on SF-36 physical health, including reduced bodily pain and improved general health, and on insomnia complaints and fatigue, were demonstrated. In this meta-analysis including all placebo-controlled clinical trials in patients with anxiety disorders to date, statistically significant and clinically meaningful advantages of Silexan over placebo treatment were found in improving somatic symptoms and physical health.

The antidepressant effects of lavender (Lavandula angustifolia Mill.): A systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND AND AIMS

Antidepressant drugs are accompanied with high rate of adverse effects. Lavender is one of the most common herbal drugs mentioned in Traditional Persian literature with potential efficacy on mental disorders and less serious side effects. Thus, the aim of this study was to determine the efficacy of lavender on depression severity by preforming a systematic review and meta-analysis.

METHODS

Databases including PubMed, Scopus, Cochrane library, Embase and Web of science were searched for relevant articles till December 2020. Quality of studies were evaluated by Jadad scale and the Cochrane collaboration tool. Depression as endpoint measure or as a subscale of any valid assessment tool was subjected to quantitative data analyses. Both fixed and random effects meta-analysis were conducted for data synthesis.

RESULTS

Out of 342 screened studies, 17 articles were included in the meta-analysis. Results showed significant efficacy of lavender in decreasing depression scores compared to the control group (pooled Standardized Mean Difference (SMD)= -0.66, 95 % CI: -0.85 to -0.46;P < 0.001, I² = 68.2 %;). Subgroup analysis proved that the effect of lavender was marginally more pronounced in participants with diagnosed depression (pooled SMD= -0.62, 95 % CI: -1.26 to 0.01, P = 0.055; I² = 88.1 %) while its effect was statistically significant in patients having other diseases with concomitant depressive symptoms (pooled SMD= -0.65, 95 % CI: -1.84 to -0.46, P < 0.001; I² = 52.1 %), and the oral route (pooled SMD= -0.56, 95 % CI: -1.07 to -0.05, P = 0.032; I² = 85.2 %;) was the most effective route of administration.

CONCLUSIONS

This systematic review and meta-analysis concluded that lavender has significant antidepressant effects. However, due to some limitations, further large clinical trials are recommended with more homogeneous populations and rigorous designs.

No Abuse Potential of Silexan in Healthy Recreational Drug Users: A Randomized Controlled Trial

BACKGROUND

Silexan is a lavender essential oil with established anxiolytic and calming efficacy. Here we asked whether there is a potential for abuse in human patients.

METHODS

We carried out a phase I abuse liability single-center, double-blind, 5-way crossover study in healthy users of recreational central nervous system depressants. They received single oral doses of 80 mg (therapeutic dose) and 640 mg Silexan, 2 mg and 4 mg lorazepam (active control) and placebo in randomized order, with 4- to 14-day washout periods between treatments. Pharmacodynamic measures included validated visual analogue scales assessing positive, negative, and sedative drug effects and balance of effects; a short form of the Addiction Research Center Inventory; and a drug similarity assessment. The primary outcome measure was the individual maximum value on the drug liking visual analogue scale during 24 hours post-dose.

RESULTS

Forty participants were randomized and 34 were evaluable for pharmacodynamic outcomes. In intraindividual head-to-head comparisons of the drug liking visual analogue scale maximum value, both doses of Silexan were rated similar to placebo whereas differences were observed between Silexan and lorazepam and between placebo and lorazepam (P < .001). These data were supported by all secondary measures of positive drug effects and of balance of effects. Differences between placebo and both doses of Silexan were always negligible in magnitude. Moreover, Silexan showed no sedative effects and was not perceived to be similar to commonly used drugs that participants had used in the past.

CONCLUSIONS

Silexan did not exhibit any abuse potential in a standard abuse potential detection screen study and is unlikely to be recreationally abused.

Pharmacological basis of the anxiolytic and antidepressant properties of Silexan®, an essential oil from the flowers of lavender

Silexan®, a proprietary essential oil manufactured by steam distillation from Lavandula angustifolia flowers showed pronounced anxiolytic effects in patients with subthreshold anxiety disorders and was also efficacious in patients with Generalized Anxiety disorder (GAD). Moreover, evidences for antidepressant-like properties of Silexan® have been observed in anxious patients suffering from comorbid depressive symptoms and in patients with mixed anxiety-depression disorder (ICD-10 F41.2). In accordance with the clinical data Silexan® is active in several behavioral models in rodents at rather low concentrations indicating potent anxiolytic and antidepressive properties. As possible mechanism of action a moderate inhibition of voltage dependent calcium channels (VDCC) has been found showing some similarities to the anxiolytic drug pregabalin. However, while pregabalin mainly inhibits P/Q-type channels by binding to a modulatory subunit, Silexan® moderately inhibits mainly T-type and N-type channels and to some extent P/Q-type channels. Unlike pregabalin Silexan® is free of hypnotic or sedative side effects and seems to be devoid of any abuse potential. With respect to its specific antidepressant like properties Silexan® improves several aspects of neuroplasticity which seems to be the common final pathway of all antidepressant drugs. As a potential mechanism of its effects on neuroplasticity an activation of the transcription factor CREB via activation of intracellular signaling kinases like PKA and MAPK has been found. Since the concentrations of Silexan® needed to inhibit VDCC function and to improve neuroplasticity are quite similar, the effects of Silexan® on PKA or MAPK could constitute a common intracellular signaling cascade leading to VDCC modulation as well as CREB activation and improved neuroplasticity.

GABAa receptor subunits expression in silver catfish (Rhamdia quelen) brain and its modulation by Nectandra grandiflora Nees essential oil and isolated compounds

Studies using silver catfish (Rhamdia quelen) as experimental models are often applied to screen essential oils (EO) with GABAergic-mediated effects. However, the expression of GABAa receptors in the silver catfish brain remains unknown. Thus, we assessed whether silver catfish express GABAa receptor subunits associated with sedation/anesthetic process and/or neurological diseases. Additionally, we evaluated the brain expression of GABAa receptor subunits in fish sedated with Nectandra grandiflora EO and its isolated compounds, the fish anesthetic (+)-dehydrofukinone (DHF), and dehydrofukinone epoxide (DFX), eremophil-11-en-10-ol (ERM) and selin-11-en-4-α-ol (SEL), which have GABAa-mediated anxiolytic-like effects in mice. The expression of the subunits gabra1, gabra2, gabra3, gabrb1, gabrd and gabrg2 in the silver catfish brain were assessed after a 24h-sedation bath by real time PCR. Since qPCR data rarely describes mechanisms of action, which are usually found through interactions with receptors, we also performed an antagonist-driven experiment using flumazenil (FMZ). Real-time PCR detected the mRNA expression of all targeted genes in R. quelen brain. The expression of gabra1 was decreased in fish sedated with ERM; EO increased gabra2, gabra3, gabrb1 and gabrg2 expression; SEL increased gabrb1, gabrd and gabrg2 expression. EO and compounds DFX, SEL and ERM induced sustained sedation in fish and FMZ-bath prompted the recovery from ERM- and DFX-induced sedation. Our results suggest that the EO, SEL, ERM and DFX sedative effects involve interaction with the GABAergic system. Our findings support the use of the silver catfish as robust and reliable experimental model to evaluate the efficacy of drugs with putative GABAergic-mediated effects.

Anxiolytic Effect of Essential Oils and Their Constituents: A Review

Essential oils are usually used in aromatherapy to alleviate anxiety symptoms. In comparison to traditional drugs, essential oils have fewer side effects and more diversified application ways, including inhalation. This review provides a comprehensive overview of studies on anxiolytic effects of essential oils in preclinical and clinical trials. Most of the essential oils used in clinical studies have been proven to be anxiolytic in animal models. Inhalation and oral administration were two common methods for essential oil administration in preclinical and clinical trials. Massage was only used in the clinical trials, while intraperitoneal injection was only used in the preclinical trails. In addition to essential oils that are commonly used in aromatherapy, essential oils from many folk medicinal plants have also been reported to be anxiolytic. More than 20 compounds derived from essential oils have shown an anxiolytic effect in rodents, while two-thirds of them are alcohols and terpenes. Monoamine neurotransmitters, amino acid neurotransmitters, and the hypothalamic-pituitary-adrenal axis are thought to play important roles in the anxiolytic effects of essential oils.

Efficacy and safety of lavender essential oil (Silexan) capsules among patients suffering from anxiety disorders: A network meta-analysis

A systematic review and network-meta analysis (NMA) were performed to estimate significance of the anxiolytic effect of lavender essential oil taken as silexan capsules versus other comparators (i.e., placebo/paroxetine/lorazepam). The outcome of interest was Hamilton Anxiety Scale (HAMA). Weighted mean differences (WMD) were calculated to estimate the treatment effect at the confidence interval of 95%. League tables were generated using treatment effect, for all pairwise comparisons, where WMD < 0 favors the column-defining treatment. Five studies were identified with a total of 524 participants receiving treatment with silexan 80 mg and 121 participants taking silexan 160 mg. The NMA results indicated that consumption of silexan 160 mg resulted in higher decline of HAMA score [WMD −1.14 (−1.10, 3.39)] in comparison to silexan 80 mg, placebo [−2.20 (−4.64, 0.24)] and paroxetine [−1.24 (−5.34, 2.85)]. The effect of silexan 80 mg was observed to be same as that of paroxetine. Overall, silexan 160 mg was noticed to be a more efficient treatment giving significant decline in HAMA score across other comparators. However, no improvements in HAMA score was observed for the group receiving lorazepam 0.5 mg when compared to silexan 160 mg, silexan 80 mg, paroxetine 20 mg, and placebo.

Effects of lavender on anxiety: A systematic review and meta-analysis

BACKGROUND

Anxiety is one of the uprising psychiatric disorders of the last decades and lavender administration has been traditionally suggested as a possible treatment. The objective of this review is to assess the efficacy of lavender, in any form and way of administration, on anxiety and anxiety-related conditions.

METHODS

The PRISMA guidelines were followed. Retrieved data were qualitatively and quantitatively synthesized. Randomized Controlled Trials (RCTs) and Non-Randomized Studies (NRSs) which investigated the efficacy of lavender, in any form and way of administration, on patients with anxiety, involved in anxiety-inducing settings or undergoing anxiety-inducing activities, compared to any type of control, without language restrictions, were identified through electronic database searches. Medline via PubMed, Scopus, Web of Science, Cochrane Library, EMBASE, and Google Scholar were systematically searched. All databases were screened up to November 2018. Risk of bias was assessed with the Cochrane risk-of-bias tool and the following domains were considered: randomization, allocation sequence concealment, blinding, incomplete outcome data, selective outcome reporting, and other biases.

RESULTS

65 RCTs (7993 participants) and 25 NRSs (1200 participants) were included in the qualitative synthesis and 37 RCTs (3964 participants) were included in the quantitative synthesis. Overall, the qualitative synthesis indicated that 54 RCTs and 17 NRSs reported at least a significant result in favor of lavender use for anxiety. The quantitative synthesis showed that lavender inhalation can significantly reduce anxiety levels measured with any validated scale (Hedges' g = -0.73 [95% CI -1.00 to -0.46], p < 0.00001, 1682 participants), as well as state anxiety (Spielberger's state-trait anxiety inventory (STAI)-State mean difference = -5.99 [95% CI -9.39 to -2.59], p < 0.001, 901 participants) and trait anxiety (STAI-Trait mean difference = -8.14 [95% CI -14.44 to -1.84], p < 0.05, 196 participants). Lavender inhalation did not show a significant effect in reducing systolic blood pressure as a physiological parameter of anxiety. A significant effect in diminishing anxiety levels was also found in favor of the use of oral Silexan® 80 mg/die for at least 6 weeks (Hamilton Anxiety Scale mean difference = -2.90 [95% CI -4.86 to -0.95], p = 0.004, 1173 participants; Zung Self-rating Anxiety Scale mean difference = -2.62 [95% CI -4.84 to -0.39], p < 0.05, 451 participants) or of the administration of massage with lavender oil (Hedges' g = -0.66 [95% CI -0.97 to -0.35], p < 0.0001, 448 participants).

DISCUSSION

The most important limitation of this review is the low average quality of available studies on the topic. The majority of included RCTs were characterized by a high overall risk of bias. Another limitation regards the heterogeneity of study designs, especially with regard to non-oral ways of administration. Overall, oral administration of lavender essential oil proves to be effective in the treatment of anxiety, whereas for inhalation there is only an indication of an effect of reasonable size, due to the heterogeneity of available studies. Lavender essential oil administered through massage appears effective, but available studies are not sufficient to determine whether the benefit is due to a specific effect of lavender. Further high-quality RCTs with more homogeneous study designs are needed to confirm these findings. Available information outlines a safe profile for lavender-based interventions, although more attention should be paid to the collection and reporting of safety data in future studies. Considering these findings, since treatments with lavender essential oil generally seem safe, and, in the case of inhalation, also simple and inexpensive, they are a therapeutic option which may be considered in some clinical contexts.

OTHER

The present systematic review was not funded and was registered in PROSPERO under the following number: CRD42019130126.

Herbal medicine for psychiatric disorders: Psychopharmacology and neuroscience-based nomenclature

Objectives: Herbs are frequently and concurrently used with prescribed drugs by patients worldwide. While clinical trials have found some herbs to be as useful as standard psychiatric drugs, most clinicians are unaware of their pharmacological mechanisms.Methods: We searched English language and other language literature with English abstracts listed in PubMed website, supplemented by additional through Google Scholar's free academic paper abstract website for publications on herbs, focussing on their clinical use in mental disorders, their neurobiology and their pharmacology.Results: A major reason for herbs remaining outside of mainstream psychiatry is that the terminology and concepts in herbal medicine are not familiar to psychiatrists in general. Many publications regarding the use of herbal medicine for psychiatric disorders are deficient in details regarding diagnosis, criteria for response and the neurobiology details compared with publications on standard psychotropic drugs. Nomenclature for herbal medicine is usually confusing and is not conducive to an easy understanding of their mode of action in psychiatric disorders.Conclusions: The recent neuroscience-based nomenclature (NbN) for psychotropics methodology would be a logical application to herbal medicine in facilitating a better understanding of the use of herbal medicine in psychiatry.

Influence of lavender oil inhalation on vital signs and anxiety: A randomized clinical trial

OBJECTIVE

To investigate the effectiveness of lavender oil (Lavandula angustifolia Mill) inhalation on anxiety, mood, and vital signs (blood pressure, respiratory rate, heart rate, and saturation) of patients undergoing oral surgery. Vital signs were considered as primary outcome measures. Paired anxiety tests were used as secondary outcome measures.

METHODS

Patients who had dental anxiety according to the Dental Anxiety Questionnaire (DAQ) were enrolled in the study. One hundred twenty-six patients who were undergoing wisdom tooth removal under local anaesthesia were randomly assigned to the lavender oil and control groups. Paired anxiety tests (Modified Dental Anxiety Scale and State-Trait Anxiety Inventory-State Scale were performed. Vital signs were noted pre-, intra-, and post-operatively. Visual analogue scale (VAS) results were assessed. The patients' degree of satisfaction was noted.

RESULTS

Pre-operative anxiety levels were similar in both groups. Significant changes in blood pressure were observed in the lavender oil group post-operatively (p < .05). Most (79.4%) of the patients in the lavender oil group enjoyed the scent, 89.68% were satisfied with their experience, and 97.62% of the patients stated that they would prefer the same protocol when needed.

CONCLUSION

Inhalation of lavender oil, which is one of the most powerful anxiolytic essential oils, reduces peri-operative anxiety and can be prospectively considered in future studies for its potential sedative characteristics in patients undergoing surgical procedures under local anaesthesia.

TRIAL REGISTRATION NUMBER

NCT03722771 (Influence of Lavender Oil on Vital Signs in Oral Surgery Patients) https://clinicaltrials.gov/ct2/show/NCT03722771.

Beneficial effects of Silexan on sleep are mediated by its anxiolytic effect

Disturbed sleep is among the most prevalent hyperarousal symptoms in anxiety disorders. Most drugs recommended for anxiety and insomnia have a sedating effect which is related to their beneficial effect on disturbed sleep. Silexan is a proprietary essential oil from Lavandula angustifolia. This drug has significant anxiolytic and sleep improving properties. Interestingly, these effects are not associated with sedation. Here we asked whether the positive effects on sleep are due to primary pharmacodynamic or secondary, disease related effects. We used the data from a double-blind, randomized study in which 212 patients were analyzed for efficacy after ten weeks' treatment with 80 mg/day Silexan or placebo. Anxiety and disturbed sleep were assessed using the Hamilton Anxiety Scale (HAMA) and the Pittsburgh Sleep Quality Index (PSQI), respectively. Regression-based mediation analysis was employed to estimate direct treatment effects and indirect effects mediated by anxiety control separately for each study group. Sobel's test was used to investigate the extent to which the mediator (HAMA change) contributes to the total effect of the independent variable (treatment) on the dependent variable (PSQI change). Compared to placebo, Silexan significantly reduced the total scores of the HAMA (p < 0.001) and of the PSQI (p = 0.002) after ten weeks, with clinically meaningful treatment group differences that were observed already after two and six weeks for HAMA and PSQI, respectively. Silexan had a statistically meaningful indirect effect on sleep (mediated by the effect on anxiety; p < 0.001) but no appreciable direct effect (p = 0.958). The ratio between the indirect and the total effect was determined to be 0.984, i. e., 98.4% of the total effect of Silexan on disturbed sleep were explained by the effect of Silexan on the symptoms of anxiety whereas 1.6% were attributable to a direct effect. The results indicate that Silexan exerts a secondary sleep improving effect almost exclusively through its anxiolytic action rather than by sedation. Findings are consistent with the drug's assumed mechanism of action.

Epistasis of HTR1A and BDNF risk genes alters cortical 5-HT1A receptor binding: PET results link genotype to molecular phenotype in depression

Alterations of the 5-HT_1A receptor and BDNF have consistently been associated with affective disorders. Two functional single nucleotide polymorphisms (SNPs), rs6295 of the serotonin 1A receptor gene (HTR1A) and rs6265 of brain-derived neurotrophic factor gene (BDNF), may impact transcriptional regulation and expression of the 5-HT_1A receptor. Here we investigated interaction effects of rs6295 and rs6265 on 5-HT_1A receptor binding. Forty-six healthy subjects were scanned with PET using the radioligand [carbonyl-¹¹C]WAY-100635. Genotyping was performed for rs6265 and rs6295. Subjects showing a genotype with at least three risk alleles (G of rs6295 or A of rs6265) were compared to control genotypes. Cortical surface binding potential (BP_ND) was computed for 32 cortical regions of interest (ROI). Mixed model was applied to study main and interaction effects of ROI and genotype. ANOVA was used for post hoc analyses. Individuals with the risk genotypes exhibited an increase in 5-HT_1A receptor binding by an average of 17% (mean BP_ND 3.56 ± 0.74 vs. 2.96 ± 0.88). Mixed model produced an interaction effect of ROI and genotype on BP_ND and differences could be demonstrated in 10 ROI post hoc. The combination of disadvantageous allelic expression of rs6295 and rs6265 may result in a 5-HT_1A receptor profile comparable to affective disorders as increased 5-HT_1A receptor binding is a well published phenotype of depression. Thus, epistasis between BDNF and HTR1A may contribute to the multifactorial risk for affective disorders and our results strongly advocate further research on this genetic signature in affective disorders.

Efficacy of Silexan in subthreshold anxiety: meta-analysis of randomised, placebo-controlled trials

Subthreshold psychiatric disorders do not fully meet the diagnostic criteria of syndromal disorders but may be associated with comparable disability. To investigate the anxiolytic effect of Silexan, an active substance from lavender oil for oral administration, in patients with subthreshold anxiety, a meta-analysis that included all published trials with Silexan in this indication was performed. Three randomised, placebo-controlled trials in subthreshold anxiety disorders (anxiety disorder not otherwise specified, restlessness and agitation, mixed anxiety and depressive disorder) were included. Eligible participants with a baseline Hamilton Anxiety Rating Scale (HAMA) total score ≥ 18 points received 1 × 80 mg/day Silexan or placebo for 10 weeks. Outcomes included the HAMA, the Pittsburgh Sleep Quality Index, the Zung Self-rating Anxiety Scale, the Clinical Global Impressions questionnaire and the SF-36 health status inventory. Data were analysed using meta-analysis based on pooled raw data of individual patients (random effects models). A total of 697 patients were assessed for efficacy. Silexan was superior to placebo in reducing the HAMA total score during 10 weeks' treatment [mean value difference, 95% confidence interval: 3.83 (1.28; 6.37) points]. Superiority was comparably pronounced for psychic and somatic anxiety as well as for observer- and self-rated anxiety. Silexan had a beneficial effect on sleep (secondary to the anxiolytic effect) without causing sedation and improved the patients' health-related quality of life. Adverse event incidence in both treatment groups was comparable [risk ratio: 1.06 (0.85; 1.33)]. Silexan has a significant and clinically meaningful anxiolytic effect in subthreshold anxiety. The results cannot be generalised to other lavender oil products.

Lavandula angustifolia Essential Oil and Linalool Counteract Social Aversion Induced by Social Defeat

Many vegetable extracts, essential oils, and their main constituents are active on the Central Nervous System (CNS). In fact, they have been used as sedatives, hypnotics, or tranquilizers for their activity in treating CNS disorders. In this research, we studied the possible activities of Lavandula angustifolia (LA) essential oil and of its main constituent, linalool, as anti-stress compounds on anxiety and social interaction and their in vitro effects on proteins (pERK and PKA) involved in the transmission of the signal. An acute intraperitoneal injection of linalool (100 mg/kg) and of LA essential oil (200 mg/kg) reduced motor activity without any anxiolytic effect, but significantly increased social interaction. Stressed mice, after being exposed to a social defeat encounter, showed heightened anxiety and social avoidance. Acute administration of LA essential oil blocked stress-induced anxiety, while linalool showed no effects. However, both compounds were capable of reversing social aversion, acting as antidepressant agents. Our results showed that linalool inhibits pERK and PKA expression in the SH-SY5Y cell, but no effect was detected with the LA essential oil. Therefore, the LA essential oil and linalool may be considered as useful alternative tools to the available traditional treatments for social stress-induced mental illnesses.

Silexan in anxiety disorders: Clinical data and pharmacological background

OBJECTIVES

Silexan is a lavender oil preparation available in 80-mg capsules. Here we review clinical trials investigating its anxiolytic efficacy, safety and tolerability in humans, as well as preclinical investigations supporting this therapeutic use.

METHODS

Besides three selected publications reporting preclinical investigations, seven clinical trials are included, of which five had a treatment duration of 6 or 10 weeks. Primary outcome measure was the HAM-A total score reduction, while single items were assessed with regard to effects on concomitant depressive symptoms and on quality of sleep.

RESULTS

In patients with subthreshold (subsyndromal) anxiety or generalised anxiety disorder (GAD), an anxiolytic effect of Silexan was evident after 2 weeks. HAM-A total score reductions between baseline and end of treatment were significantly superior to placebo in patients with subthreshold anxiety and comparable with those achieved under lorazepam or paroxetine in patients with GAD. In addition, Silexan had beneficial effects on typical concomitant symptoms of anxiety disorders, such as impaired sleep, somatic complaints, co-morbid depression or decreased quality of life. Except for mild gastrointestinal symptoms, Silexan did not induce any adverse effects and did not cause drug interactions, sedation or withdrawal symptoms at daily doses of 80 or 160 mg.

CONCLUSIONS

Silexan is a safe and effective treatment in anxiety disorders.

Citrus essential oils inhalation by mice: Behavioral testing, GCMS plasma analysis, corticosterone, and melatonin levels evaluation

The use of orange essential oils (EOs) as a complementary treatment is very common in Brazilian popular culture. The levels of melatonin (MEL) and corticosterone (CORT) hormones were investigated simultaneously, by the Luminex™ immunoassay system in mice plasma, after Citrus aurantium and Citrus sinensis EOs inhalation for 30 min. The plasma was analyzed by headspace through gas chromatography coupled to mass spectrometry for investigation of the EO components. Mice were submitted to behavioral testing to research anxiolytic-like, sedative, and antidepressant-like effects. The inhalation of atmosphere obtained from vaporization of 10% solution of this Citrus EO separately did not affect MEL or CORT plasma levels; that is, the MEL and CORT levels did not present variation in function of the EO in the schedule used. On the other hand, the imipramine positive control used altered the level of MEL as expected. The EO constituents were detected in plasma at different ratios that is present in inhaled EO. Behavioral tests showed that the inhalation of 10% C. sinensis EO presents an anxiolytic-like and sedative effect. Thus, C. sinensis EO can be a valuable tool for treatment of the anxiety disturbs, apparently without interference with MEL and CORT physiological levels.

Silexan in generalized anxiety disorder: investigation of the therapeutic dosage range in a pooled data set

Silexan, a special active substance produced from Lavandula angustifolia, is efficacious in subsyndromal anxiety at a dose of 80 mg/day, but its effective dosage in generalized anxiety disorder (GAD) has yet to be defined. In two double-blind, placebo-controlled trials, daily doses of 10, 40, 80, and 160 mg silexan were administered for 10 weeks. A total of 925 adults with GAD according to Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria and a Hamilton Anxiety Scale (HAMA) total score of at least 18 points were analyzed for efficacy. We assessed the change versus baseline for the HAMA and the Covi Anxiety Scale, the Clinical Global Impressions scale, the Sheehan Disability Scale, and the SF-36 health status questionnaire using analysis of variance and covariance. Silexan 160 mg/day was superior to placebo for all efficacy outcomes investigated, with responder rates exceeding 60% on the basis of HAMA and Clinical Global Impressions criteria. For the 80 mg/day dosage, superiority over placebo could be shown in one trial as well as in the pooled analysis. The risk of adverse events under silexan was similar to placebo for all dosages investigated. In GAD silexan 160 mg/day is efficacious whereas 80 mg/day may represent the lower end of the therapeutic range. Daily doses up to 160 mg were well tolerated.

Essential oil of lavender in anxiety disorders: Ready for prime time?

Anxiety disorders are some of the most common psychiatric disorders, with potentially debilitating consequences on individual function. Existing pharmacotherapies for anxiety disorders are limited by delay to therapeutic effect, dependence, tolerance, withdrawal, and abuse potential. Therefore, safe and evidence-based complementary or alternative therapies may be important allies in the care of patients with anxiety disorders. Essential oils are lipophilic and concentrated botanical extracts that exhibit many properties of drugs, although they are not Food and Drug Administration approved and have limitations characteristic of herbal preparations. Lavender essential oil has an extensive anecdotal history of anxiolytic benefit that has recently been supported by clinical efficacy studies. The 2 primary terpenoid constituents of lavender essential oil, linalool and linalyl acetate, may produce an anxiolytic effect in combination via inhibition of voltage-gated calcium channels, reduction of 5HT1A receptor activity, and increased parasympathetic tone. The objectives of this article are to provide a brief overview of lavender oil in aromatherapy, explore variability in the constituents of lavender oil, summarize its pharmacology and safety profile, as well as describe its body of research that has been conducted for anxiety.

The influence of the rs6295 gene polymorphism on serotonin-1A receptor distribution investigated with PET in patients with major depression applying machine learning

Major depressive disorder (MDD) is the most common neuropsychiatric disease and despite extensive research, its genetic substrate is still not sufficiently understood. The common polymorphism rs6295 of the serotonin-1A receptor gene (HTR1A) is affecting the transcriptional regulation of the 5-HT_1A receptor and has been closely linked to MDD. Here, we used positron emission tomography (PET) exploiting advances in data mining and statistics by using machine learning in 62 healthy subjects and 19 patients with MDD, which were scanned with PET using the radioligand [carbonyl-¹¹C]WAY-100635. All the subjects were genotyped for rs6295 and genotype was grouped in GG vs C allele carriers. Mixed model was applied in a ROI-based (region of interest) approach. ROI binding potential (BP_ND) was divided by dorsal raphe BP_ND as a specific measure to highlight rs6295 effects (BP_Div). Mixed model produced an interaction effect of ROI and genotype in the patients' group but no effects in healthy controls. Differences of BP_Div was demonstrated in seven ROIs; parahippocampus, hippocampus, fusiform gyrus, gyrus rectus, supplementary motor area, inferior frontal occipital gyrus and lingual gyrus. For classification of genotype, 'RandomForest' and Support Vector Machines were used, however, no model with sufficient predictive capability could be computed. Our results are in line with preclinical data, mouse model knockout studies as well as previous clinical analyses, demonstrating the two-pronged effect of the G allele on 5-HT_1A BP_ND for, we believe, the first time. Future endeavors should address epigenetic effects and allosteric heteroreceptor complexes. Replication in larger samples of MDD patients is necessary to substantiate our findings.

Mood Therapeutics: Novel Pharmacological Approaches for Treating Depression

INTRODUCTION

Real-world effectiveness trials suggest that antidepressant efficacy is limited in many patients with mood disorders, underscoring the urgent need for novel therapeutics to treat these disorders. Areas covered: Here, we review the clinical evidence supporting the use of novel modulators for the treatment of mood disorders, including specific glutamate modulators such as: 1) high-trapping glutamatergic modulators; 2) subunit (NR2B)-specific N-methyl-D-aspartate (NMDA) receptor antagonists; 3) NMDA receptor glycine-site partial agonists; and 4) metabotropic glutamate receptor (mGluR) modulators. We also discuss other promising, non-glutamatergic targets for potential rapid antidepressant effects in mood disorders, including the cholinergic system, the glucocorticoid system, and the inflammation pathway, as well as several additional targets of interest. Clinical evidence is emphasized, and non-pharmacological somatic treatments are not reviewed. In general, this paper only explores agents available in the United States. Expert commentary: Of these novel targets, the most promising - and the ones for whom the most evidence exists - appear to be the ionotropic glutamate receptors. However, moving forward will require us to fully embrace the goal of personalized medicine and will require health professionals to pre-emptively identify potential responders.

The relevance of 'mixed anxiety and depression' as a diagnostic category in clinical practice

According to ICD-10 criteria, mixed anxiety and depressive disorder (MADD) is characterized by co-occurring, subsyndromal symptoms of anxiety and depression, severe enough to justify a psychiatric diagnosis, but neither of which are clearly predominant. MADD appears to be very common, particularly in primary care, although prevalence estimates vary, often depending on the diagnostic criteria applied. It has been associated with similarly pronounced distress, impairment of daily living skills, and reduced health-related quality of life as fully syndromal depression and anxiety. Although about half of the patients affected remit within a year, non-remitting patients are at a high risk of transition to a fully syndromal psychiatric disorder. The validity and clinical usefulness of MADD as a diagnostic category are under debate. It has not been included in the recently released DSM-5 since the proposed diagnostic criteria turned out to be not sufficiently reliable. Moreover, reviewers have disputed the justification of MADD based on divergent results regarding its prevalence and course, diagnostic stability over time, and nosological inconsistencies between subthreshold and threshold presentations of anxiety and depressive disorders. We review the evidence in favor and against MADD and argue that it should be included into classification systems as a diagnostic category because it may enable patients to gain access to appropriate treatment early. This may help to reduce patients' distress, prevent exacerbation to a more serious psychiatric disorder, and ultimately reduce the societal costs of this very common condition.

Efficacy of orally administered Silexan in patients with anxiety-related restlessness and disturbed sleep--A randomized, placebo-controlled trial

The anxiolytic effect of Silexan, a patented active substance with an essential oil produced from Lavandula angustifolia flowers, was investigated in patients with anxiety-related restlessness and disturbed sleep. 170 out-patients with a diagnosis of restlessness (ICD-10 R45.1), a Hamilton Anxiety Scale (HAMA) total score ≥18 points and ≥2 points for HAMA items 'Tension' and 'Insomnia' participated in this randomized, double-blind trial and received 80mg Silexan or placebo once daily for 10 weeks. Patients with clinically important other psychiatric or neurological disorders potentially interfering with the assessment of treatment efficacy were excluded. Outcome variables were the HAMA as well as the Pittsburgh Sleep Quality Index (PSQI), the Zung Self-rating Anxiety Scale, a State Check inventory and the Clinical Global Impressions questionnaire. In the Silexan group the HAMA total score decreased from an average of 25.5±6.0 points at baseline to 13.7±7.0 points at treatment end, compared to a decrease from 26.5±6.1 to 16.9±9.8 for placebo, corresponding to decreases of 12.0 and 9.3 points (marginal means), respectively (group difference: p=0.03, ANCOVA with factor treatment and baseline value as covariate). In all outcome measures the treatment effect of Silexan was more pronounced than with placebo. According to the HAMA, 48.8% and 33.3% of the patients were responders (Silexan, placebo; reduction ≥50%; p=0.04) and 31.4% and 22.6% achieved remission (HAMA<10; p=0.20). 33.7% (Silexan) and 35.7% (placebo) of the participants reported adverse events. The study confirms the calming and anxiolytic efficacy of Silexan.

A Systematic Review of the Anxiolytic-Like Effects of Essential Oils in Animal Models

The clinical efficacy of standardized essential oils (such as Lavender officinalis), in treating anxiety disorders strongly suggests that these natural products are an important candidate source for new anxiolytic drugs. A systematic review of essential oils, their bioactive constituents, and anxiolytic-like activity is conducted. The essential oil with the best profile is Lavendula angustifolia, which has already been tested in controlled clinical trials with positive results. Citrus aurantium using different routes of administration also showed significant effects in several animal models, and was corroborated by different research groups. Other promising essential oils are Citrus sinensis and bergamot oil, which showed certain clinical anxiolytic actions; along with Achillea wilhemsii, Alpinia zerumbet, Citrus aurantium, and Spiranthera odoratissima, which, like Lavendula angustifolia, appear to exert anxiolytic-like effects without GABA/benzodiazepine activity, thus differing in their mechanisms of action from the benzodiazepines. The anxiolytic activity of 25 compounds commonly found in essential oils is also discussed.

Phytopharmaceutical treatment of anxiety, depression, and dementia in the elderly: evidence from randomized, controlled clinical trials

Based on subgroup analyses of randomized, controlled clinical trials, we review the efficacy of three phytopharmaceutical drugs, respectively of the corresponding active substances silexan® (WS® 1265, lavender oil) in anxiety disorders, WS® 5570 (Hypericum extract) in major depression, and EGb 761® (Ginkgo biloba extract) in Alzheimer, vascular, or mixed type dementia, in elderly patients aged ≥ 60 years. Four trials were eligible in each indication. Meta-analyses and analyses based on pooled raw data showed that the three drugs were significantly superior to placebo in the elderly subset, and that their treatment effects reflected in the main outcome measures (Hamilton Anxiety scale, Hamilton Depression scale, Neuropsychiatric Inventory) were comparable with those observed in the original trials without age restrictions. The results confirm the efficacy of the three herbal active substances in elderly patients of ≥ 60 years of age. In anxiety, depression, and dementia, they thus represent efficacious and well-tolerated alternatives to synthetic drugs.