OnabotulinumtoxinA for the treatment of major depressive disorder: a phase 2 randomized, double-blind, placebo-controlled trial in adult females

New and emerging treatments for major depressive disorder

Major depressive disorder (MDD) affects a substantial portion of the population; however, much is still unknown about the pathophysiology of this disorder. Treatment resistance highlights the heterogeneous nature of MDD and the need for treatments to target more than monoamine neurotransmission. This review summarizes research into the new and emerging targets of MDD. These include drugs such as psychedelics, antibiotics, opioid modulators, neuropeptides, and onabotulinumtoxin. Neuromodulatory treatments such as light based therapies and neuromodulation involving either magnetic or electrical stimulation are also discussed. Almost all interventions, pharmacological and neuromodulation, were trialed as adjunctive treatments to an antidepressant. Most research has been conducted on psychedelics, with trials suggesting rapid antidepressant and anti-suicidal effects. Trial findings, tolerability, study design limitations and quality of research have been considered throughout this review. There remains challenges in forming recommendations with the current research at present. With there being considerable interest into the research of new and emerging treatments-in particular, psychedelics-there may be scope in the future to form more robust recommendations.

A novel approach to treating post-stroke depression: administration of Botulinum Toxin A via local facial injection

Background

Post-stroke depression (PSD) is a frequent complication following a stroke, characterized by prolonged feelings of sadness and loss of interest, which can significantly impede stroke rehabilitation, increase disability, and raise mortality rates. Traditional antidepressants often have significant side effects and poor patient adherence, necessitating the exploration of more suitable treatments for PSD. Previous researchers and our research team have discovered that Botulinum Toxin A (BoNT-A) exhibits antidepressant effects. Therefore, our objective was to assess the efficacy and side effects of BoNT-A treatment in patients with PSD.

Methods

A total of 71 stroke patients meeting the inclusion criteria were allocated to the two group. 2 cases were excluded due to severe neurological dysfunction that prevented cooperation and 4 cases were lost follow-up. Ultimately, number of participants in the BoNT-A group (n = 32) and Sertraline group (n = 33). Treatment efficacy was evaluated 1, 2, 4, 8 and 12 weeks post-treatment.

Results

There were no significant differences in baseline characteristics between the two groups (p > 0.05). Both groups exhibited comparable treatment efficacy, with fewer side effects observed in the BoNT-A group compared to the Sertraline group. BoNT-A therapy demonstrated significant effects as early as the first week (p < 0.05), and by the 12th week, there was a notable decrease in neuropsychological scores, significantly lower than the baseline level. The analysis revealed significant differences in measurements of the Hamilton Depression Scale (HAMD) (F(770) = 12.547, p = 0.000), Hamilton Anxiety Scale (HAMA) (F(951) = 10.422, p = 0.000), Self-Rating Depression Scale (SDS) (F(1385) = 10.607, p = 0.000), and Self-Rating Anxiety Scale (SAS) (F(1482) = 11.491, p = 0.000).

Conclusion

BoNT-A treatment effectively reduces depression symptoms in patients with PSD on a continuous basis.

A Critical View on New and Future Antidepressants

For the first time after many decades, many new antidepressants have been approved and many more are under various stages of development and will soon be available in the market. The new drugs present a range of new mechanisms of action with benefits in terms of speed of action, tolerability and range of treatable disorders. Neurosteroids have been recently approved and their rapid benefit may extend from postpartum depression to anxious depression and bipolar depression, dextromethorphan and bupropion combination may prove useful in major depression but also in treatment resistant depression, dextromethadone is a possible augmentation in partial antidepressant response, psychedelic drugs have the potential of long lasting benefits after a single administration, though are still experimental treatments. Botulinum has the same advantage of psychedelics of a single administration and its antidepressant effects may last for weeks or more. Further potentially interesting new antidepressant mechanisms include new drug targets, drug repurposing and genetic or epigenetic manipulations. It is therefore important that clinicians are kept up to date with new evidence so that new evidence can be rapidly translated into clinical practice.

Botulinum Toxin Injections for Psychiatric Disorders: A Systematic Review of the Clinical Trial Landscape

Botulinum toxin type A (BONT-A) has shown promise in improving the mood-related symptoms of psychiatric disorders by targeting muscles linked to the expression of negative emotions. We conducted a systematic review of past and ongoing efficacy trials of BONT-A therapy for psychiatric disorders to identify relevant trends in the field and discuss the refinement of therapeutic techniques. A comprehensive search for published clinical trials using BONT-A injections for psychiatric disorders was performed on 4 May 2023 through OVID databases (MEDLINE, Embase, APA PsycINFO). Unpublished clinical trials were searched through the ClinicalTrials.gov and International Clinical Trial Registry Platform public registries. The risk of bias was assessed using the JBI Critical Appraisal tools for use in systematic reviews. We identified 21 studies (17 published, 4 unpublished clinical trials) involving 471 patients. The studies focused on evaluating the efficacy of BONT-A for major depressive, borderline personality, social anxiety, and bipolar disorders. BONT-A was most commonly injected into the glabellar area, with an average dose ranging between 37.75 U and 44.5 U in published studies and between 32.7 U and 41.3 U in unpublished trials. The results indicated significant symptom reductions across all the studied psychiatric conditions, with mild adverse effects. Thus, BONT-A appears to be safe and well-tolerated for psychiatric disorders of negative affectivity. However, despite the clinical focus, there was a noted shortage of biomarker-related assessments. Future studies should focus on pursuing mechanistic explorations of BONT-A effects at the neurobiological level.

Comparative effectiveness of two different doses of botulinum toxin A for the treatment of mild to moderate depression

OBJECTIVE

Botulinum toxin A has been shown to be effective in managing depression. This study aimed to evaluate the antidepressant and antianxiety effects of two different doses of botulinum toxin A in patients with mild to moderate depression.

METHODS

A total of 140 patients diagnosed with mild to moderate depression at the Department of Neurology of the Second Affiliated Hospital of Soochow University from September 2020 to September 2021 were enrolled for the study. The patients were allocated into two groups and treated with two different doses of botulinum toxin A (50 units or 100 units). Depression scores (HAMD, HAMA, SDS, and SAS) were evaluated at baseline and 1, 2, 4, 8, and 12 weeks after treatment.

RESULTS

There was a significant improvement in the depressive and anxiety symptoms following treatment with the botulinum toxin A after 12 weeks compared to the baseline. However, there were no significant differences between the two groups. Further, the factor scores of anxiety/somatization, blocking, sleep disorder, and cognitive disorder were significantly decreased after 12 weeks of treatment with 50 units of botulinum toxin A compared to the baseline (P < 0.05). Further, the factor scores of somatic and mental anxiety were significantly decreased at different time points after treatment with 50 units of botulinum toxin A compared to the baseline (P < 0.05).

CONCLUSION

Local injections of 50 units and 100 units of botulinum toxin A shows equal efficacy. Therefore, 50 units of botulinum toxin A could be used clinically to manage mild to moderate depression.

The etiology, diagnostics, and treatment of the spasm of the near reflex - a narrative review

Physiological adaptation of the eye to the visual perception of near objects consists of the "near triad": convergence, accommodation, and pupil miosis. Normally, these tend to revert when one stops fixating on a near object. Spasm of the near reflex (SNR) is a pathological phenomenon, which manifests itself by the persistence of the above-mentioned adjustments, which prevents the eye from returning to its relaxed state. In this narrative review, we aim to summarize the etiology, diagnostics, treatment, and prevention of SNR. The literature review was performed by searching online databases. The clinical presentation of SNR is diverse; it presents as isolated accommodative spasm more frequently than impairment of all three components of the near triad. Patients usually present with fluctuations in visual acuity, blurred vision, diplopia, and asthenopia. The etiology is not fully understood. Potential causes include neuroanatomic, organic, and psychogenic disorders. The diagnosis is clinical, based on the constellation of symptoms and assessment of the near triad. The diagnostic golden standard is a cycloplegic examination of refraction, preferably using cyclopentolate hydrochloride (1%, 0.5%, or 0.1% solution). The first-line treatment requires the administration of a cycloplegic drug in combination with plus lenses, flipper lenses, optical fogging, or miotics. For secondary cases, causal treatment should be implemented. Prevention of SNR should be based on eliminating modifiable risk factors. We propose including screening for SNR symptoms in every ophthalmic examination, especially among patients with psychogenic or neural disorders, after brain trauma, or young adults spending much time in front of computer screens.

Effects of glabellar botulinum toxin injections on resting-state functional connectivity in borderline personality disorder

Meta-analyses suggest a sustained alleviation of depressive symptoms through glabellar botulinum toxin (BTX) injections. This can be explained by the disruption of facial feedback loops, which may moderate and reinforce the experience of negative emotions. Borderline personality disorder (BPD) is characterized by excessive negative emotions. Here, a seed-based resting-state functional connectivity (rsFC) analysis following BTX (N = 24) or acupuncture (ACU, N = 21) treatment in BPD is presented on areas related to the motor system and emotion processing. RsFC in BPD using a seed-based approach was analyzed. MRI data were measured before and 4 weeks after treatment. Based on previous research, the rsFC focus was on limbic and motor areas as well as the salience and default mode network. Clinically, after 4 weeks both groups showed a reduction of borderline symptoms. However, the anterior cingulate cortex (ACC) and the face area in the primary motor cortex (M1) displayed aberrant rsFC after BTX compared to ACU treatment. The M1 showed higher rsFC to the ACC after BTX treatment compared to ACU treatment. In addition, the ACC displayed an increased connectivity to the M1 as well as a decrease to the right cerebellum. This study shows first evidence for BTX-specific effects in the motor face region and the ACC. The observed effects of BTX on rsFC to areas are related to motor behavior. Since symptom improvement did not differ between the two groups, a BTX-specific effect seems plausible rather than a general therapeutic effect.

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.

The pluripotential evolution and journey of Botox (onabotulinumtoxinA)

Clinical use of onabotulinumtoxinA evolved based on strategic, hypothesis-driven applications, as well as serendipitous observations by physicians and patients. The success of onabotulinumtoxinA in blepharospasm and strabismus led to its study in other head and neck dystonias, followed by limb dystonia, tremor, and spasticity. The aesthetic use of onabotulinumtoxinA followed initial reports from patients of improved facial lines after injections for facial dystonias and hemifacial spasm. Although patients with dystonias and spasticity regularly reported that their local pain improved after injections, onabotulinumtoxinA was not systematically explored for chronic migraine until patients began reporting headache improvements following aesthetic injections. Clinicians began assessing onabotulinumtoxinA for facial sweating and hyperhidrosis based on its inhibition of acetylcholine from sympathetic cholinergic nerves. Yet another line of research grew out of injections for laryngeal dystonia, whereby clinicians began to explore other sphincters in the gastrointestinal tract and eventually to treatment of pelvic sphincters; many of these sphincters are innervated by autonomic nerves. Additional investigations in other autonomically mediated conditions were conducted, including overactive bladder and neurogenic detrusor overactivity, achalasia, obesity, and postoperative atrial fibrillation. The study of onabotulinumtoxinA for depression also grew out of the cosmetic experience and the observation that relaxing facial muscle contractions associated with negative emotions may improve mood. For approved indications, the safety profile of onabotulinumtoxinA has been demonstrated in the formal development programs and post-marketing reports. Over time, evidence has accumulated suggesting clinical manifestations of systemic effects, albeit uncommon, particularly with high doses and in vulnerable populations. Although onabotulinumtoxinA is approved for approximately 26 indications across multiple local regions, there are 15 primary indication uses that have been approved in most regions, including the United States, Europe, South America, and Asia. This review describes many uses for which AbbVie has not sought and/or received regulatory approval and are mentioned for historical context only.

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 Therapy for Psychiatric Disorders in Clinical Practice: A Retrospective Case Study

Inhibiting the facial expression of negative emotions via botulinum toxin A (BTX) has been shown to mitigate symptoms of clinical depression in randomized controlled trials. This retrospective case study sought to reproduce the beneficial effects of BTX in a naturalistic setting for major depressive disorder and collect casuistic data on its effect on other mental disorders. Moreover, we describe symptom development across multiple treatment cycles with BTX, and assess the implementation of additional injection targets in the lower face region. Participants were N = 51 adult psychiatric outpatients mainly seeking treatment for depression. Over 50% suffered from comorbid psychiatric conditions, predominantly generalized anxiety disorder (GAD) or borderline personality disorder (BPD). A pre-post case series design was adapted. All participants received BTX-injections in the glabellar region on at least one occasion. Some received additional injections in the mouth region and over multiple treatment cycles. Treatment response was followed up by self-rated scales at varying time intervals post treatment. The results showed that BTX may yield favorable outcomes across multiple and comorbid mental disorders, especially, however, for patients suffering from depression. It potentially prevents the recurrence of clinical symptoms if applied regularly. Adding additional regions of the face does not seem to be superior over applying it to the glabellar region alone. The results add to the growing evidence that BTX therapy is effective in alleviating symptoms of depression. Positive effects can be sustained and reinstated, when applied over multiple treatment cycles. Observed symptom reduction in other psychiatric disorders was less pronounced. Further research is needed to understand the mechanisms by which BTX therapy reduces psychiatric symptoms.

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.

Real-world characteristics of European patients receiving SNRIs as first-line treatment for major depressive disorder

BACKGROUND

Serotonin-norepinephrine reuptake inhibitors (SNRIs) are among the most frequently prescribed antidepressants (ADs) for major depressive disorder (MDD), with an increasing trend in the last decade. Given the relative dearth of information regarding rationales for their preferred use as first-line ADs in the broad clinical routine, the present study systematically investigated real-world characteristics of MDD patients prescribed either SNRIs or other AD substances across different countries and treatment settings.

METHODS

In the present secondary analyses based on a large European, multi-site, naturalistic and cross-sectional investigation with a retrospective assessment of treatment outcome, we firstly defined the proportion of MDD patients receiving SNRIs as first-line AD psychopharmacotherapy and secondly compared their sociodemographic and clinical characteristics to those patients prescribed alternative first-line ADs during their current major depressive episode (MDE).

RESULTS

Within the total sample of 1410 MDD patients, 336 (23.8 %) received first-line SNRIs. Compared to other ADs, SNRIs were significantly associated with inpatient care, suicidality and treatment resistance during the current MDE, and a longer lifetime duration of psychiatric hospitalizations. Moreover, greater severity of depressive symptoms at study entry, higher daily doses of the administered ADs, as well as more frequent prescriptions of psychopharmacotherapeutic add-on strategies in general and antipsychotic augmentation in particular, were significantly related to first-line SNRIs.

CONCLUSIONS

Considering the limitations of a cross-sectional and retrospective study design, our data point towards a preferred use of first-line SNRIs in a generally more severely ill MDD patients, although they did not lead to superior treatment outcomes compared to alternative ADs.

Neurocircuitry underlying the antidepressant effect of retrograde facial botulinum toxin in mice

BACKGROUNDS

Botulinum toxin type A (BoNT/A) is extensively applied in spasticity and dystonia as it cleaves synaptosome-associated protein 25 (SNAP25) in the presynaptic terminals, thereby inhibiting neurotransmission. An increasing number of randomized clinical trials have suggested that glabellar BoNT/A injection improves depressive symptoms in patients with major depressive disorder (MDD). However, the underlying neuronal circuitry of BoNT/A-regulated depression remains largely uncharacterized.

RESULTS

Here, we modeled MDD using mice subjected to chronic restraint stress (CRS). By pre-injecting BoNT/A into the unilateral whisker intrinsic musculature (WIM), and performing behavioral testing, we showed that pre-injection of BoNT/A attenuated despair- and anhedonia-like phenotypes in CRS mice. By applying immunostaining of BoNT/A-cleaved SNAP25 (cl.SNAP25₁₉₇), subcellular spatial localization of SNAP25 with markers of cholinergic neurons (ChAT) and post-synaptic membrane (PSD95), and injection of monosynaptic retrograde tracer CTB-488-mixed BoNT/A to label the primary nucleus of the WIM, we demonstrated that BoNT/A axonal retrograde transported to the soma of whisker-innervating facial motoneurons (wFMNs) and subsequent transcytosis to synaptic terminals of second-order neurons induced central effects. Furthermore, using transsynaptic retrograde and monosynaptic antegrade viral neural circuit tracing with c-Fos brain mapping and co-staining of neural markers, we observed that the CRS-induced expression of c-Fos and CaMKII double-positive neurons in the ventrolateral periaqueductal grey (vlPAG), which sent afferents to wFMNs, was down-regulated 3 weeks after BoNT/A facial pre-administration. Strikingly, the repeated and targeted silencing of the wFMNs-projecting CaMKII-positive neurons in vlPAG with a chemogenetic approach via stereotactic injection of recombinant adeno-associated virus into specific brain regions of CRS mice mimicked the antidepressant-like action of BoNT/A pre-treatment. Conversely, repeated chemogenetic activation of this potential subpopulation counteracted the BoNT/A-improved significant antidepressant behavior.

CONCLUSION

We reported for the first time that BoNT/A inhibited the wFMNs-projecting vlPAG excitatory neurons through axonal retrograde transport and cell-to-cell transcytosis from the injected location of the WIM to regulate depressive-like phenotypes of CRS mice. For the limited and the reversibility of side effects, BoNT/A has substantial advantages and potential application in MDD.

Botulinum toxin A (BoNT/A) for the treatment of depression: A randomized, double-blind, placebo, controlled trial in China

BACKGROUND

Depression is characterized by low moods, anhedonia, and social avoidance. Effective and acceptable treatments are required for depression. Positive effects on mood have been observed in patients with depression after treatment with botulinum toxin A (BoNT/A).

METHODS

A total of 88 patients with depression were randomly assigned to BoNT/A (n = 56) and placebo (saline, n = 22) groups. The primary objective was to determine the change in the 17-item version of the Hamilton Depression Rating Scale (HAMD), 12 weeks after the treatments when compared with the baseline.

RESULTS

The BoNT/A and placebo groups did not differ significantly in all the collected baseline characteristics. However, there was a significant improvement in the depressive symptoms of the BoNT/A group compared to those of the placebo group throughout the 12-week follow-up period. This was according to the measurements of HAMD (F (1, 370) = 9.094, P = 0.0027), Self-rating Depression Scale (SDS) (F (1, 370) = 11.26, P < 0.001), Hamilton Anxiety Scale (HAMA) (F (1, 410) = 8.673, P = 0.0034) and Self-rating Anxiety Scale (SAS) (F (1, 379) = 5.788, P = 0.017). Furthermore, the effectiveness was even higher at the end of the study period.

LIMITATIONS

The limitations include the absence of a multicenter study and an inadequate number of cases. Additionally, the mechanism of BoNT/A antidepression was not studied.

CONCLUSION

This study showed that a single treatment with BoNT/A may accomplish a strong and sustained alleviation of depression in patients.

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.

Neuronal effects of glabellar botulinum toxin injections using a valenced inhibition task in borderline personality disorder

Previous studies have indicated that glabellar botulinum toxin (BTX) injections may lead to a sustained alleviation of depression. This may be accomplished by the disruption of a facial feedback loop, which potentially mitigates the experience of negative emotions. Accordingly, glabellar BTX injection can attenuate amygdala activity in response to emotional stimuli. A prototypic condition with an excess of negative emotionality and impulsivity accompanied by elevated amygdala reactivity to emotional stimuli is borderline personality disorder (BPD). In order to improve the understanding of how glabellar BTX may affect the processing of emotional stimuli and impulsivity, we conducted a functional magnetic resonance imaging (fMRI) study. Our hypotheses were (1) glabellar BTX leads to increased activation in prefrontal areas during inhibition performance and (2) BTX decreases amygdala activity during the processing of emotional stimuli in general. Using an emotional go-/no-go paradigm during fMRI, the interference of emotion processing and impulsivity in a sample of n = 45 women with BPD was assessed. Subjects were randomly assigned to BTX treatment or serial acupuncture (ACU) of the head. After 4 weeks, both treatments led to a reduction in the symptoms of BPD. However, BTX treatment was specifically associated with improved inhibition performance and increased activity in the motor cortex. In addition, the processing of negative emotional faces was accompanied by a reduction in right amygdala activity. This study provides the first evidence that glabellar BTX injections may modify central neurobiological and behavioural aspects of BPD. Since the control treatment produced similar clinical effects, these neurobiological findings may be specific to BTX and not a general correlate of symptomatic improvement.

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.

Investigational Drugs for the Treatment of Depression (Part 2): Glutamatergic, Cholinergic, Sestrin Modulators, and Other Agents

Many investigational drugs with antidepressant activity are currently explored in different phases of clinical research, with indications such as major depressive disorder, treatment-resistant major depression, bipolar depression, post-partum depression, and late-life depression. Although the vast majority of the antidepressants in clinical use are based on the monoaminergic hypothesis of depression, recent data supported the launching on the market of two new, non-monoamine-modulating drugs. Esketamine for treatment-resistant major depression and brexanolone for post-partum depression are two exceptions from the monoaminergic model, although their use is still limited by high costs, unique way of administration (only intravenously for brexanolone), physicians’ reluctance to prescribe new drugs, and patients’ reticence to use them. Glutamatergic neurotransmission is explored based on the positive results obtained by intranasal esketamine, with subanesthetic intravenous doses of ketamine, and D-cycloserine, traxoprodil, MK-0657, AXS-05, AVP-786, combinations of cycloserine and lurasidone, or dextromethorphan and quinidine, explored as therapeutic options for mono- or bipolar depression. Sestrin modulators, cholinergic receptor modulators, or onabotulinumtoxinA have also been investigated for potential antidepressant activity. In conclusion, there is hope for new treatments in uni- and bipolar depression, as it became clear, after almost 7 decades of monoamine-modulating antidepressants, that new pathogenetic pathways should be targeted to increase the response rate in this population.

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.

Botulinum toxin therapy: past, present and future developments

Although botulinum toxin (BT) is now being used in a large number of different indications in numerous medical specialties, there is still dynamic and rapid development. Treatment algorithms were improved by the introduction of BT short-interval therapy, BT high-dose therapy and improved dosing guidelines. Ultrasound guidance may be helpful in special situations. New indication areas including depression and inflammatory processes are being explored. Drug development projects are mainly focusing on onabotulinumtoxinA analogues, some are addressing liquid preparations and modifications of BT's duration of action. Recombinant BT may simplify production processes. Cell-based assays for potency measurement will soon be required by registration authorities. Treatment algorithms will be further refined and indications will be expanded. New indication areas are still uncertain. BT type A will remain the drug substance of choice. Removal of complexing proteins seems logical. Whether there is a need for BT drugs with modified duration of action and for liquid preparations, is unclear. Bringing BT therapy to those who need it, is the biggest challenge. Current high-price business models need to be changed, either by employing a biosimilar registration approach or by referring to companies from countries where business models are based on different cost structures.

Toxicology and pharmacology of botulinum and tetanus neurotoxins: an update

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to devise improved therapies based on antibodies and chemical drugs. Recently, major results have been obtained with human monoclonal antibodies and with single chain antibodies that have allowed one to neutralize the metalloprotease activity of botulinum neurotoxin type A1 inside neurons. In addition, a method has been devised to induce a rapid molecular evolution of the metalloprotease domain of botulinum neurotoxin followed by selection driven to re-target the metalloprotease activity versus novel targets with respect to the SNARE proteins. At the same time, an intense and wide spectrum clinical research on novel therapeutics based on botulinum neurotoxins is carried out, which are also reviewed here.

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.

Novel Antidepressants in the Pipeline (Phase II and III): A Systematic Review of the US Clinical Trials Registry

Introduction There is an imminent need for faster-acting and more effective antidepressants beyond the monoaminergic hypothesis.

Methods We systematically searched the US Clinical Trials registry for antidepressant compounds with completed phase II and III trials. Compounds that demonstrated significant superiority over placebo in the primary outcome measure in the latest phase of phase II and III trials were identified. The collateral information was gathered via a PubMed search and press releases.

Results Nine compounds were identified. AXS-05 (a combination of dextromethorphan and bupropion) and ansofaxine hydrochloride showed a positive result over placebo in a phase III study for major depressive disorder or treatment-resistant depression. MIJ821, nitrous oxide, psilocybin, ayahuasca, facial injection of botulinum toxin A, prasterone, and casopitant demonstrated at least one positive result in phase II trials. Ayahuasca showed a greater response rate than placebo at week one, indicating the rapid antidepressant effect.

Discussion These new compounds with novel mechanisms of action are expected to provide a greater variety of treatment options for depression if preliminary positive results are confirmed.

Periorbital injections of botulinum toxin a: a novel therapeutic option for convergence spasm in neuropsychiatric disorders

PURPOSE

Convergence spasm (CS, spasm of near reflex) is characterized by transient attacks of convergence, miosis and accommodation, often associated with functional neurological disorders. To date, no simple and efficient treatment option is available for CS. This study investigates whether periorbital botulinum toxin injections as used in essential blepharospasm are also a treatment option in these patients.

METHODS

All patients with convergence spasm having been treated with periorbital BoNTA injections in the department of neuro-ophthalmology were identified. Data were extracted from patient files concerning details and subjective effectiveness of botulinum toxin injections and relation to psychiatric or neurological disorders. Patients reporting with a history of closed-head trauma or organic neurologic pathologies possibly causing CS were excluded. A telephone assessment with a standardized questionnaire was performed to evaluate mental health issues as a trigger, as well as the long-term effect and satisfaction with periorbital injections.

RESULTS

Of 16 patients treated with periorbital botulinum toxin injections for convergence spasm, 9 patients reported depression and/or anxiety disorders ongoing or in the past. A median number of 3 injections (range 1-13) was administered with a variable effect (relief of symptoms) between no effect and effect of up to more than 12 weeks. A longitudinal follow-up revealed ongoing symptoms in five patients.

CONCLUSIONS

Periorbital botulinum toxin injections are less invasive than injections in the medial rectus muscle and can be a bridging therapeutic option in patients with CS. Mental health exploration is important due to psychiatric comorbidity.

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.

Efficacy of onabotulinumtoxinA in the treatment of unipolar major depression: Systematic review, meta-analysis and meta-regression analyses of double-blind randomised controlled trials

BACKGROUND

OnabotulinumtoxinA is a novel therapeutic intervention whose mechanism of action is believed to modify the negative facial feedback, thus abating symptoms of depression. This putative new antidepressant agent offers minimal systemic side effects and negligible risk of pharmacological interactions. We set out to examine the evidence for the use of onabotulinumtoxinA in major depression.

METHODS

A systematic search of the literature identified double-blind randomised controlled trials (RCTs) investigating the use of onabotulinumtoxinA in the treatment of major depression versus placebo. Data, reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA), was combined in meta-analyses (PROSPERO registration ID: CRD42020183538).

RESULTS

The search identified five RCTs (four double-blind) comparing onabotulinumtoxinA to placebo. OnabotulinumtoxinA was more effective than placebo when administered within the 20-40 IU dose range in double-blind RCTs. The analysis was free of publication bias and significantly heterogeneous. Meta-regression analyses indicated that onabotulinumtoxinA was more efficacious in women and in higher doses in female patients and less effective with polypharmacy, especially when an increasing number of antidepressants were prescribed. The effectiveness of onabotulinumtoxinA was higher in more recently published double-blind RCTs.

CONCLUSION

The meta-analysis supports the efficacy of the intervention with the results being highly heterogeneous across studies. In view of the heterogeneity of the findings and the significant moderators of benefit (sex, year of study completion and the interaction between sex and dose), more research is required to better understand the role of onabotulinumtoxinA in the treatment of depression.

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.

Onabotulinumtoxin A Improves Psychological Aspects in Chronic Migraine Patients

Background: Chronic migraine (CM) affects 5.4% of the Kuwaiti population. It is associated with significant headache-related disability, psychiatric comorbidity and reduced quality of life. The aim of this study is to assess the efficacy of Onabotulinumtoxin A on psychological aspects of chronic migraine patients. Methods: This prospective study over 36 months included chronic migraine patients in a tertiary headache center. Eligible patients met International Classification of Headache Disorders disorders-third edition, beta version (ICHD-III) revision criteria for chronic migraine. Patients with history of psychiatric or medical problems other than migraine disorders were excluded. Patients who received less than 4 injections cycles of Onabotulinumtoxin A were excluded. Identified patients received 155 units of Onabotulinumtoxin A quarterly according to the Phase III Research Evaluating Migraine Prophylaxis Therapy Trail (PREEMPT) protocol. Quality of life, the seven-item Generalized Anxiety Disorder (GAD-7) scores, the nine-item Patient Health Questionnaire (PHQ9), and the Pittsburgh Sleep Quality Index (PSQI) were collected before injection and at the end of the study. Mean comparison tests were performed using the independent sample t-test to assess the effects of Onabotulinumtoxin A on quality of life and comorbid symptoms of anxiety, depression, and quality of sleep. Results: The study identified 131 chronic migraine patients with a mean age of 44.92 years, mean disease duration of 12.20 years and a mean treatment sessions of 7.58. In their last visit, most of our sample showed improvement in quality of life (81%), GAD-7 (81%), PHQ9 (79%), and PSQ1 (76%). The mean score of patient satisfaction was 7.21. Onabotulinumtoxin A treatment for CM improved quality of life significantly (72.92 vs. 103.62; P < 0.0001). It was also associated with significant reduction in anxiety [GAD-7 (12.00 vs. 6.61; P < 0.0001)] and depression [PHQ-9 (17.91 vs. 12.52; P < 0.0001)] scores, as well as reduced difficulty in sleeping [PSQI (12.60 vs. 6.66; P < 0.0001)] at the last visit. Conclusion: Prophylactic Onabotulinumtoxin A treatment for CM was associated with significant improvement of quality of life, reduction in symptoms of anxiety and depression, as well as improved symptoms of poor sleep.

Botulinum Neurotoxin Therapy for Depression: Therapeutic Mechanisms and Future Perspective

Depression is one of the most common mental disorders, which causes global burden. Antidepressants and psychotherapies are the mainstay of treatment for depression, which have limited efficacy. Thus, alternative approaches for preventing and treating depression are urgently required. Recent clinical trials and preclinical researches have clarified that peripheral facial injection of botulinum neurotoxin type A (BoNT/A) is a rapid, effective and relative safe therapy for improving some symptoms of depression. Despite its safety and efficacy, the underlying therapeutic mechanisms of BoNT/A for depression remains largely unclear. In the present review, we updated and summarized the clinical and preclinical evidence supporting BoNT/A therapy for the treatment of depression. We further discussed the potential mechanisms underlying therapeutic effects of BoNT/A on depression. Notably, we recently identified that the anti-depressant effects of BoNT/A associated with up-regulation of 5-HT levels and brain-derived neurotrophic factor (BDNF) expression in the hippocampus in a preclinical mouse model. In summary, these studies suggest that BoNT/A therapy is a potential effective and safe intervention for the management of depression. However, fundamental questions remain regarding the future prospects of BoNT/A therapy, including safety, efficacy, dose-response relationships, identification of potential predictors of response, and the precise mechanisms underlying BoNT/A therapy.

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

The World Health Organization estimates the number of people suffering from depression to be over 264 million. Current monoamine transmission modulating therapeutics, even with proper adherence and acceptable tolerability, are not effective for nearly one third of the patients, leading clinicians to explore other therapeutic options such as electroconvulsive therapy, transcranial magnetic stimulation, ketamine infusions, and, more recently, glabellar botulinum toxin, BoNT, injections. The scale and mechanism of antidepressant action of BoNT is unclear and maybe hypothetically attributed to the disruption of proprioceptive facial feedback reinforcing negative emotions. Here we verify the antidepressant effect of botulinum toxin by analysis of over 40 thousand BoNT treatment reports out of thirteen million postmarketing safety reports in the FDA Adverse Event Reporting System, FAERS. The results of the analysis indicate that patients who received BoNT injections to treat hyperhidrosis, facial wrinkles, migraine prophylaxis, spasticity, and spasms, had a significantly lower number of depression reports when compared to patients undergoing different treatments for the same conditions. These findings suggest that the antidepressant effect of BoNT is significant, and, surprisingly, is observed for a broad range of injection sites.

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.