Postmarketing safety surveillance data reveals antidepressant effects of botulinum toxin across various indications and injection sites

Botox (onabotulinumtoxinA) mechanism of action

Studies in the 1920s found that botulinum neurotoxin type A (BoNT/A) inhibited the activity of motor and parasympathetic nerve endings, confirmed several decades later to be due to decreased acetylcholine release. The 1970s were marked by studies of cellular mechanisms aided by use of neutralizing antibodies as pharmacologic tools: BoNT/A disappeared from accessibility to neutralizing antibodies within minutes, although it took several hours for onset of muscle weakness. The multi-step mechanism was experimentally confirmed and is now recognized to consist broadly of binding to nerve terminals, internalization, and lysis or cleavage of a protein (SNAP-25: synaptosomal associated protein-25 kDa) that is part of the SNARE (Soluble NSF Attachment protein REceptor) complex needed for synaptic vesicle docking and fusion. Clinical use of the BoNT/A product onabotulinumtoxinA was based on its ability to reduce muscle contractions via inhibition of acetylcholine from motor terminals. Sensory mechanisms of onabotulinumtoxinA have now been identified, supporting its successful treatment of chronic migraine and urgency in overactive bladder. Exploration into migraine mechanisms led to anatomical studies documenting pain fibers that send axons through sutures of the skull to outside the head-a potential route by which extracranial injections could affect intracranial processes. Several clinical studies have also identified benefits of onabotulinumtoxinA in major depression, which have been attributed to central responses induced by feedback from facial muscle and skin movement. Overall, the history of BoNT/A is distinguished by basic science studies that stimulated clinical use and, conversely, clinical observations that spurred basic research into novel mechanisms of action.

Botulinum neurotoxins: Future innovations

Botulinum neurotoxins (BoNTs) are multi-domain proteins whose potent and selective actions on nerve endings have led to innovations in both basic and clinical science. The various BoNT domains are responsible for binding to gangliosides and proteins associated with nerve cell membranes, internalization into the cell, and cleavage of one or more SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins necessary for vesicle docking and fusion. Novel modifications to BoNT molecules, such as the creation of chimeras, helped identify the protein domains responsible for various aspects of BoNT action, such as localized effects. Other molecular modifications have been introduced in attempts to increase the specificity of BoNTs for autonomic or sensory neurons, with the ultimate goal of optimizing therapeutic selectivity. This research, in turn, has led to the development of BoNT-based proteins that can target non-SNARE substrates such as phosphatase and tensin homolog (PTEN). Still others are developing different BoNT serotypes, subtypes, or variants that are longer- or shorter-acting or have faster onset for various clinical purposes. New formulations of BoNTs that provide convenience for both patients and physicians are under investigation. Novel clinical uses are being evaluated for onabotulinumtoxinA, including in the prevention of post-operative atrial fibrillation. All these innovations capitalize on the unique properties of BoNTs, which continue to intrigue scientists and clinicians across numerous fields of study.

Botulinum Toxin Treatment for Depression: A New Paradigm for Psychiatry

Multiple randomized double-blind placebo-controlled trials have shown that botulinum toxin A (BoNT/A), when injected into the frown musculature, is an antidepressant. This review outlines the conceptual narrative behind this treatment modality, starting with theory developed by Charles Darwin. We develop the concept of emotional proprioception and discuss how the muscles of facial expression play an important role in relaying valenced information to the brain's emotional neuroanatomical circuit. We review the role of facial frown musculature as the brain's barometer and transmitter of negatively valanced emotional information. The direct connections between the corrugator muscles and the amygdala are reviewed, and these provide a neuroanatomical circuit that is a logical target for treatment with BoNT/A. The centrality of amygdala dysfunction in the pathogenesis of many psychiatric disorders, and the evidence that BoNT/A modulates amygdala activity, provides the mechanistic link between BoNT/A and its antidepressant activity. Animal models of BoNT/A's antidepressant effects confirm the evolutionary conservation of this emotional circuit. The clinical and theoretical implications of this evidence, as it relates to the potential treatment of a broad range of psychiatric disorders by BoNT/A, is discussed. The ease of administration, long duration, and favorable side effect profile of this therapy is reviewed in the context of existing antidepressant treatments.

Modulation of amygdala activity for emotional faces due to botulinum toxin type A injections that prevent frowning

According to the facial feedback hypothesis, when we see an angry or happy face, we contract or flex the relevant muscles to recreate the expression to assist in identifying and experiencing the emotion reflected. We investigated the facial feedback hypothesis by using botulinum toxin type A (onabotulinumtoxinA; onabotA) injections to induce temporary paralysis in the glabellar muscles (responsible for frowning) and measured functional brain activity during the processing of emotional faces. Ten females viewed pictures of happy and angry faces during two functional magnetic resonance imaging (fMRI) scan sessions: one prior (Pre) to onabotA and one following (Active) onabotA injections. We found Pre vs. Active onabotA modulation of activity in the amygdala for both happy and angry faces, as well as modulation of activity in the fusiform gyrus for happy faces. Consistent with our predictions, preventing frowning through inhibition of glabellar muscle contraction altered amygdala processing for emotional faces. The modulation of amygdala and fusiform gyrus activity following onabotA may reflect compensatory processes in a neuroanatomical circuit involved in emotional processing that is engaged when facial feedback is impaired. These data contribute to a growing literature suggesting that inhibition of glabellar muscle contraction alters neural activity for emotional processing.Clinical Trials.gov registration number: NCT03373162.

Mood symptoms in cervical dystonia: Relationship with motor symptoms and quality of life

Background

Cervical dystonia (CD) has a high prevalence of anxiety and depression. The relationship between motor severity, mood symptoms and QoL is unclear and how to adequately assess these is also unknown. Instruments like the BAI, BDI and HADS are often used but items within these relating to somatic symptoms might influence the results.

Methods

Patients with idiopathic cervical dystonia (CD) were included. The BAI, BDI, HADS, CIDP58 and TWSTRS2- severity score were used for assessment of motor, mood and QoL symptoms. Pearson's correlations between motor and non-motor symptom scores were assessed. The psychometric properties of the psychiatric tools were measured and principal component analysis performed after identifying items that could correspond to somatic symptoms.

Results

201 participants were included. 42% of participants had either significant depression or anxiety symptoms or both when measured by BAI and BDI and 51% of patients met criteria on HADS. HADS-A and HADS-D, BAI and BDI were poorly correlated with TWSTRS2-S. The HADS-A and HADS-D both showed strong correlation with the sleep subdomain of CDIP58. Psychometric and principal component analysis on 149/201 participants did not reveal factor loadings consistent with the a priori somatic groupings. However mean scores were higher for somatic items.

Conclusion

A good score on the CDIP58, a commonly used tool, does not indicate mild disease severity or minimal mood symptoms. Minimal motor symptoms, similarly, also does not imply a positive QoL. Clinicians should be mindful on ideal methods for performing a holistic assessment of CD patients. This likely warrants a combination of motor, QoL and mood assessment tools.

Intraoperative abobotulinumtoxinA alleviates pain after surgery and improves general wellness in a translational animal model

Pain after surgery remains a significant healthcare challenge. Here, abobotulinumtoxinA (aboBoNT-A, DYSPORT) was assessed in a post-surgical pain model in pigs. Full-skin-muscle incision and retraction surgery on the lower back was followed by intradermal injections of either aboBoNT-A (100, 200, or 400 U/pig), vehicle (saline), or wound infiltration of extended-release bupivacaine. We assessed mechanical sensitivity, distress behaviors, latency to approach the investigator, and wound inflammation/healing for 5-6 days post-surgery. We followed with immunohistochemical analyses of total and cleaved synaptosomal-associated protein 25 kD (SNAP25), glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor protein-1(Iba1), calcitonin gene-related peptide (CGRP) and substance P (SP) in the skin, dorsal root ganglia (DRG) and the spinal cord of 400 U aboBoNT-A- and saline-treated animals. At Day 1, partial reversal of mechanical allodynia in aboBoNT-A groups was followed by a full reversal from Day 3. Reduced distress and normalized approaching responses were observed with aboBoNT-A from 6 h post-surgery. Bupivacaine reversed mechanical allodynia for 24 h after surgery but did not affect distress or approaching responses. In aboBoNT-A-treated animals cleaved SNAP25 was absent in the skin and DRG, but present in the ipsilateral dorsal horn of the spinal cord. In aboBoNT-A- versus saline-treated animals there were significant reductions in GFAP and Iba1 in the spinal cord, but no changes in CGRP and SP. Analgesic efficacy of aboBoNT-A appears to be mediated by its activity on spinal neurons, microglia and astrocytes. Clinical investigation to support the use of aboBoNT-A as an analgesic drug for post-surgical pain, is warranted.

Botulinum Toxin in Facial Aesthetics Affects the Emotion Process: A Meta-analysis of Randomized Controlled Trials

This study aimed to conduct a meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of the btulinum toxin-A (BT-A) in patiets with mood disorders. PubMed, Scopus, Web of Science, Cochrane Library and LILACS were searched without restrictions up to July 2022. The PICOS strategy was used for the selection of studies and risk-of-bias assessment was performed using Cochrane's tool for RCTs. RCTs were included if they compared BT-A treatment on facial muscles in patients with mood disorders to placebo. After assessment of the full texts, seven studies were selected. Five studies had low risk of bias for the generation of random sequence and blinding of participants and professional domains. A total of four studies showed a low risk of bias for the allocation concealment and blinding of the evaluation of the domain results. The domain of selective reports showed a low risk of bias in all included studies. However, four studies presented a high risk of bias for the domain of other biases. The meta-analysis was based on the mean difference or standardized mean difference between the BT-A and placebo groups for each selected trial and revealed that the BT-A group showed a significant improvement in the symptoms of depression when compared to placebo. This study revealed that the BT-A application into mimic muscles of the upper third of the face improves the mood disorders, but it was not possible to guarantee whether the aesthetic benefits can contribute to reducing the severity of the depressive state.

Glabellar Botulinum Toxin Injection Improves Depression Scores: A Systematic Review and Meta-Analysis

BACKGROUND

Depression is a leading cause of disability worldwide. Preliminary evidence suggests that glabellar onabotulinumtoxinA injections improve depression scores with few side effects compared to current first-line antidepressant medications. The authors' review reports on these studies, hypothesizing that glabellar onabotulinumtoxinA injections can be an alternative safe and effective treatment for depression.

METHODS

A systematic review and meta-analysis of the relevant literature was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed, Cochrane Library, Embase, and Scopus databases were searched in August of 2020 using the keywords ["botox" OR "botulinum"] AND ["mood" OR "depression"] for articles published between 1980 and 2020. Prospective studies and randomized controlled trials on the use of glabellar onabotulinumtoxinA injections for the primary purpose of treating depression were considered. The primary endpoint for the meta-analysis was the mean difference in primary depression scores after treatment, along with a second endpoint of the standardized mean difference in depression scores among treated patients including all nine studies.

RESULTS

Of the 499 reviewed articles, nine studies were included that reported improvement in mean depression scores from baseline. All five randomized controlled trials reported an improvement in mean depression scores at 6 weeks after treatment, with a weighted average change of -8.39 points ( p < 0.0001). The aggregate standardized mean difference from baseline to the primary endpoint across all nine prospective studies was -1.61 SD ( p < 0.0001).

CONCLUSION

Meta-analysis and systematic review of the included studies provide support for an antidepressant effect of glabellar onabotulinumtoxinA injections.

Treatment of Depression with Botulinum Toxin

Injection of botulinum toxin (BoNT) into the glabellar region of the face is a novel therapeutic approach in the treatment of depression. This treatment method has several advantages, including few side effects and a long-lasting, depot-like effect. Here we review the clinical and experimental evidence for the antidepressant effect of BoNT injections as well as the theoretical background and possible mechanisms of action. Moreover, we provide practical instructions for the safe and effective application of BoNT in the treatment of depression. Finally, we describe the current status of the clinical development of BoNT as an antidepressant and give an outlook on its potential future role in the management of mental disorders.

Clinical effects of glabellar botulinum toxin injections on borderline personality disorder: A randomized controlled trial

BACKGROUND

Inhibition of frowning via injections of botulinum toxin A (BTX) into the glabellar region has shown beneficial effects in the treatment of major depression. Preliminary research suggests that improvements in the affective domain are not depression-specific, but may also translate to other psychiatric disorders.

AIM

This 16-week, single-blind, two-center randomized controlled trial investigated the influence of BTX on clinical symptoms of borderline personality disorder (BPD).

METHODS

Fifty-four patients with BPD were randomly assigned to treatment with BTX (n = 27) or a minimal acupuncture (ACU) control condition (n = 27). Clinical outcomes were followed at 2, 4, 6, 8, 12, and 16 weeks. Primary endpoint was the relative score change on the Zanarini Rating Scale for Borderline Personality Disorder (ZAN-BPD) 8 weeks after baseline relative to the control group and adjusted for treatment center. Secondary and additional outcome variables were self-rated borderline symptoms, comorbid symptoms of depression, psychological distress, and clinical global impression.

RESULTS

Participants showed significant improvements at the primary efficacy endpoint in both treatment groups (BTX: M = -0.39, SD = 0.39; ACU: M = -0.35, SD = 0.42), but no superior effect of the BTX condition in comparison with the control intervention was found-F(1,5323) = 0.017, p = 0.68). None of the secondary or additional outcomes yielded significant group differences. Side effects were mild and included headache, transient skin or muscle irritations, and dizziness.

CONCLUSION

Evidence regarding the efficacy of BTX for BDP remains limited, and the design of adequate control conditions presents an opportunity for further research.ClinicalTrials.gov registry: Botulinum Toxin A for Emotional Stabilization in Borderline Personality Disorder (BPD), NCT02728778, https://clinicaltrials.gov/ct2/show/NCT02728778.

Postmarketing safety surveillance data reveals protective effects of botulinum toxin injections against incident anxiety

Randomized controlled trials (RCTs) have shown an antidepressant effect of glabellar botulinum toxin (BoNT) injections. In the FDA Adverse Event Reporting System (FAERS) database, BoNT injection is associated with reduced incidence rates of depression across various non-psychiatric indications, which confirms the previous findings independently of specific expectations to an antidepressant effect of BoNT. The rationale of using BoNT to treat depression is to interrupt proprioceptive body feedback that may reinforce negative emotions. Negative emotions also occur in other mental disorders, suggesting a transdiagnostic therapeutic potential of BoNT in psychiatry. Here we report an analysis of the FAERS database, in which we found that, compared to alternative treatments, BoNT injections were associated with lower incidence of anxiety symptoms and related disorders. Among seven indications/injection sites, we found this protective effect of BoNT in cosmetic use/facial muscles, migraine/facial and head muscles, spasms and spasticity/upper and lower limbs, torticollis and neck pain/neck muscles, and sialorrhea/parotid and submandibular glands (reporting odds ratios 0.79-0.27). These findings are encouraging for possible future RCTs on the use of BoNT as a treatment for anxiety and related disorders.

Common osteoporosis drug associated with increased rates of depression and anxiety

Osteoporosis affects over 10 million Americans over 50. Bisphosphonate therapy, mainly alendronate, is amongst the most prescribed treatments for the disease. The use of alendronate and other bisphosphonates has been associated with depressive symptoms in recent case reports. In this study we quantified this association by analyzing over 100,000 adverse events reports from the Food and Drug Administration Adverse Events Reporting System (FAERS) and the World Health Organization’s (WHO) global database for adverse drug reactions, ADRs, VigiAccess. We found that alendronate therapy is significantly associated with depression and anxiety when compared to other first-line osteoporosis treatments. The reported risk of depressive ADRs was found to be over 14-fold greater in patients taking alendronate under the age of 65 and over fourfold greater for patients over 65 compared to the control. Several hypotheses concerning the molecular mechanism of the observed association of alendronate and depressive symptoms were discussed.

BOTOX® counteracts the innate anxiety-related behaviours in correlation with increased activities of key antioxidant enzymes in the hippocampus of ageing experimental mice

Cholinergic crisis and oxidative stress in the hippocampus of the brain have been known to induce anxiety disorders upon ageing. BOTOX® is a widely used therapeutic form of botulinum neurotoxin that acts by inhibiting the release of acetylcholine (ACh) from the nerve terminals at the neuromuscular junction. BOTOX® can migrate from the muscle to the brain through retrograde axonal transport and modulate neuroplasticity. While a mild dose of BOTOX® has been used to manage various neurological deficits and psychiatric complications including depression, the efficacy and experimental evidence for its anxiolytic effects and antioxidant properties remain limited. In this study, we have investigated the effect of BOTOX® on the innate anxiety-like behaviours in ageing mice upon exposure to different behavioural paradigms like open field test, elevated plus maze and light-dark box test, and estimated the enzymatic activities of key antioxidants in the hippocampus. Results revealed that animals injected with a mild intramuscular dosage of BOTOX® showed reduced level of innate anxiety-related symptoms and increased activities of hippocampal antioxidant enzymes compared to the control group. This study strongly supports that BOTOX® could be implemented to prevent or treat anxiety and hippocampal oxidative stress resulting from ageing, emotional and mood disorders.

Botulinum toxin for the management of depression: An updated review of the evidence and meta-analysis

Botulinum toxin (BTX) treatment of glabellar frown lines is one of the most common procedures in aesthetic medicine. In addition to its cosmetic effect, the neurotoxin has been shown to have a positive influence on mood and affect. Several randomized clinical trials (RCTs) have examined the effect of botulinum toxin on the treatment of depression. Combining the results of the five RCTs in a random effects meta-analysis revealed that patients treated with BTX showed a more intense improvement of depressive symptoms in comparison to subjects that received placebo injections (d = 0.98). Despite methodological limitations, the results of this study emphasize the effectiveness of BTX in the treatment of depression and therefore pave the way for its use in the field of psychiatry.

Exploring Emotional Distress, Psychological Traits and Attitudes in Patients with Chronic Migraine Undergoing OnabotulinumtoxinA Prophylaxis versus Withdrawal Treatment

This explorative cross-sectional study aims at exploring emotional distress, psychological profiles, and the attitude towards receiving psychological support in eighty-seven patients with chronic migraine (CM) undergoing OnabotulinumtoxinA prophylactic treatment (OBT-A, n = 40) or withdrawal treatment (WT, n = 47). The outcomes were explored through a specific battery of questionnaires. 25% of patients undergoing OBT-A and almost half of the patients undergoing WT reported psychological distress of at least moderate-severe level, respectively. Coping strategies, self-efficacy, and perceived social support were similar in the two groups. Patients undergoing OBT-A presented lower psychological inflexibility than patients undergoing WT. Predictors of higher psychological distress were low perceived social support by friends, low self-efficacy, and higher avoidance strategies. In both groups, most of the patients evaluated receiving psychological support to be useful (79%). The potential beneficial effects of OBT-A on the severity of symptoms and psychological distress might further support its role in the multidisciplinary management of patients with CM. Identifying patients with psychological vulnerabilities who may benefit from psychological support is relevant in patients with CM.

Efficacy and Safety of Botulinum Toxin vs. Placebo in Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Major depressive disorder (MDD) is a serious mental disorder that represents a substantial public health problem. Several trials have been undertaken to investigate the role of botulinum toxin type A (BTX-A) in the treatment of MDD, but the conclusions were controversial. To examine the efficacy and safety of BTX-A vs. placebo on patients with a clinical diagnosis of MDD, we conducted this systematic review and meta-analysis. Methods: A systematic search was conducted for all relevant randomized controlled trials (RCTs) in PubMed and Web of Science from inception to June 17, 2020. All published studies that investigated the efficacy and safety of BTX-A injections on patients with a clinical diagnosis of MDD were included. The overall effect size was summarized using a random-effects meta-analysis model. The primary outcomes of the present meta-analysis were the changes in depressive rating scale at week 6 after BTX-A injection compared with placebo. The safety of BTX-A injections also was assessed. Results: Five RCTs with a total of 417 participants (189 patients in the BTX-A group, 228 patients in placebo group) were eligible in this meta-analysis. The results indicated an overall positive effect of BTX-A injections for reducing the depressive symptoms of patients with MDD (Hedges' g, -0.82; 95% CI, -1.38 to -0.27) with large effect size. Differences are likely explained by the dose of BTX-As and the gender of the participants. Our findings also highlighted that BTX-A injections were generally well-tolerated, with only mild and temporary adverse events reported. Conclusions: The present meta-analysis provides evidence that BTX-A injections are associated with a statistically significant improvement in depressive symptoms. BTX-A injections are generally safe and may provide a new, alternative option for the treatment of depression.