Canadian Network for Mood and Anxiety Treatments (CANMAT) 2023 Update on Clinical Guidelines for Management of Major Depressive Disorder in Adults: Réseau canadien pour les traitements de l'humeur et de l'anxiété (CANMAT) 2023 : Mise à jour des lignes directrices cliniques pour la prise en charge du trouble dépressif majeur chez les adultes.

BACKGROUND: The Canadian Network for Mood and Anxiety Treatments (CANMAT) last published clinical guidelines for the management of major depressive disorder (MDD) in 2016. Owing to advances in the field, an update was needed to incorporate new evidence and provide new and revised recommendations for the assessment and management of MDD in adults. METHODS: CANMAT convened a guidelines editorial group comprised of academic clinicians and patient partners. A systematic literature review was conducted, focusing on systematic reviews and meta-analyses published since the 2016 guidelines. Recommendations were organized by lines of treatment, which were informed by CANMAT-defined levels of evidence and supplemented by clinical support (consisting of expert consensus on safety, tolerability, and feasibility). Drafts were revised based on review by patient partners, expert peer review, and a defined expert consensus process. RESULTS: The updated guidelines comprise eight primary topics, in a question-and-answer format, that map a patient care journey from assessment to selection of evidence-based treatments, prevention of recurrence, and strategies for inadequate response. The guidelines adopt a personalized care approach that emphasizes shared decision-making that reflects the values, preferences, and treatment history of the patient with MDD. Tables provide new and updated recommendations for psychological, pharmacological, lifestyle, complementary and alternative medicine, digital health, and neuromodulation treatments. Caveats and limitations of the evidence are highlighted. CONCLUSIONS: The CANMAT 2023 updated guidelines provide evidence-informed recommendations for the management of MDD, in a clinician-friendly format. These updated guidelines emphasize a collaborative, personalized, and systematic management approach that will help optimize outcomes for adults with MDD.

A randomized sham-controlled trial of high-dosage accelerated intermittent theta burst rTMS in major depression: study protocol.

BACKGROUND: Intermittent theta burst stimulation (iTBS), a novel form of repetitive transcranial magnetic stimulation (rTMS), can be administered in 1/10th of the time of standard rTMS (~ 3 min vs. 37.5 min) yet achieves similar outcomes in depression. The brief nature of the iTBS protocol allows for the administration of multiple iTBS sessions per day, thus reducing the overall course length to days rather than weeks. This study aims to compare the efficacy and tolerability of active versus sham iTBS using an accelerated regimen in patients with treatment-resistant depression (TRD). As a secondary objective, we aim to assess the safety, tolerability, and treatment response to open-label low-frequency right-sided (1 Hz) stimulation using an accelerated regimen in those who do not respond to the initial week of treatment. METHODS: Over three years, approximately 230 outpatients at the Centre for Addiction and Mental Health and University of British Columbia Hospital, meeting diagnostic criteria for unipolar MDD, will be recruited and randomized to a triple blind sham-controlled trial. Patients will receive five consecutive days of active or sham iTBS, administered eight times daily at 1-hour intervals, with each session delivering 600 pulses of iTBS. Those who have not achieved response by the week four follow-up visit will be offered a second course of treatment, regardless of whether they initially received active or sham stimulation. DISCUSSION: Broader implementation of conventional iTBS is limited by the logistical demands of the current standard course consisting of 4-6 weeks of daily treatment. If our proposed accelerated iTBS protocol enables patients to achieve remission more rapidly, this would offer major benefits in terms of cost and capacity as well as the time required to achieve clinical response. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04255784.

Managing substance use in patients receiving therapeutic repetitive transcranial magnetic stimulation: A scoping review.

Repetitive Transcranial Magnetic Stimulation (rTMS) is an invaluable treatment option for neuropsychiatric disorders. Co-occurring recreational and nonmedical substance use can be common in those presenting for rTMS treatment, and it is unknown how it may affect the safety and efficacy of rTMS for the treatment of currently approved neuropsychiatric indications. This scoping review aimed to map the literature on humans receiving rTMS and had a history of any type of substance use. The search identified 274 articles providing information on inclusion/exclusion criteria, withdrawal criteria, safety protocols, type of rTMS and treatment parameters, adverse events and effect on primary outcomes that related to substance use. There are neurophysiological effects of substance use on cortical excitability, although the relevance to clinical rTMS practice is unknown. The current literature supports the safety and feasibility of delivering rTMS to those who have co-occurring neuropsychiatric disorder and substance use. However, specific details on how varying degrees of substance use alters the safety, efficacy, and mechanisms of rTMS remains poorly described.

GABAergic signaling in alcohol use disorder and withdrawal: pathological involvement and therapeutic potential.

Alcohol is one of the most widely used substances. Alcohol use accounts for 5.1% of the global disease burden, contributes substantially to societal and economic costs, and leads to approximately 3 million global deaths yearly. Alcohol use disorder (AUD) includes various drinking behavior patterns that lead to short-term or long-lasting effects on health. Ethanol, the main psychoactive molecule acting in alcoholic beverages, directly impacts the GABAergic system, contributing to GABAergic dysregulations that vary depending on the intensity and duration of alcohol consumption. A small number of interventions have been developed that target the GABAergic system, but there are promising future therapeutic avenues to explore. This review provides an overview of the impact of alcohol on the GABAergic system, the current interventions available for AUD that target the GABAergic system, and the novel interventions being explored that in the future could be included among first-line therapies for the treatment of AUD.

The use of theta burst stimulation in patients with schizophrenia - A systematic review.

Transcranial magnetic stimulation (TMS) can offer therapeutic benefits and provide value in neurophysiological research. One of the newer TMS paradigms is theta burst stimulation (TBS) which can be delivered in two patterns: continuous (cTBS - inducing LTD-like effects) and intermittent (iTBS - inducing LTP-like effects). This review paper aims to explore studies that have utilized TBS protocols over different areas of the cortex to study the neurophysiological functions and treatment of patients with schizophrenia. PubMed was searched using the following keywords "schizophrenia", "schizoaffective", or "psychosis", and "theta burst stimulation". Out of the 90 articles which were found, thirty met review inclusion criteria. The inclusion criteria included studying the reported effect (clinical, physiological, or both) of at least one session of TBS on human subjects, and abstracts (at minimum) must have been in English. The main target areas included prefrontal cortex (12 studies - 10 dorsolateral prefrontal cortex (DLPFC), 2 dorsomedial prefrontal cortex (DMPFC)) vermal cerebellum (5), and temporo-parietal cortex (8). Other target areas included inferior parietal lobe (2), and motor cortex (3). TBS neurophysiological effect was explored in 5 studies using functional magnetic resonance image (fMRI), magnetic resonance spectroscopy (MRS), electroencephalography (EEG), electromyography (EMG) and positron emission topography (PET) scan. Overall, TBS can offer great therapeutic potential as it is well-tolerated, feasible, and has few, if any, adverse effects. TBS may be targeted to treat specific symptomatology, as an augmenting intervention to pharmacotherapy, or even improving patient's insight into their diagnosis.

Treatment outcomes in major depressive disorder in patients with comorbid alcohol use disorder: A STAR*D analysis.

INTRODUCTION: Guidance on Major Depressive Disorder (MDD) treatment in those with comorbid Alcohol Use Disorder (AUD) is limited. We performed a secondary analysis on the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, examining the association between comorbid AUD and depression outcomes. METHODS: STAR*D was a real-world effectiveness trial starting with citalopram in level 1. Non-responding participants progressed through 3 other sequential treatment levels with different switch or augmentation options. Antidepressant outcomes were compared between MDD (n = 2826) and comorbid MDD and AUD (n = 864). Logistic regressions were performed to evaluate remission and response predictors in the total STAR*D sample and the AUD-comorbidity interaction. RESULTS: Chi-squared tests showed no significant difference in response or remission rates from depression between groups across treatment levels. Higher Hamilton Rating Scale for Depression (HRSD) score was associated with overall lower odds of remission in treatment level 1 (OR = 0.93, p < 0.001) and 2 (OR = 0.95, p < 0.001), with no significant interaction with comorbid AUD. Higher baseline suicidality had overall lower odds of remission in level 1 (OR = 0.82, p < 0.001) and 2 (OR = 0.1, p < 0.001), but with comorbid AUD compared to no AUD, suicidality increased odds of level 1 remission (OR = 1.30, p = 0.012). In comorbid AUD in level 2, venlafaxine was associated with lower odds of remission (OR = 0.13, p = 0.013) and response (OR = 0.12, p = 0.006); bupropion with lower odds of response (OR = 0.22, p = 0.024). LIMITATIONS: Open label study design and lack of alcohol use data. CONCLUSIONS: Comorbid AUD may interact with predictors of antidepressant response in MDD and using venlafaxine or bupropion may be less effective. Addressing this comorbidity requires unique assessment and treatment approaches.

Isolating sensory artifacts in the suprathreshold TMS-EEG signal over DLPFC.

Combined transcranial magnetic stimulation and electroencephalography (TMS-EEG) is an effective way to evaluate neurophysiological processes at the level of the cortex. To further characterize the TMS-evoked potential (TEP) generated with TMS-EEG, beyond the motor cortex, we aimed to distinguish between cortical reactivity to TMS versus non-specific somatosensory and auditory co-activations using both single-pulse and paired-pulse protocols at suprathreshold stimulation intensities over the left dorsolateral prefrontal cortex (DLPFC). Fifteen right-handed healthy participants received six blocks of stimulation including single and paired TMS delivered as active-masked (i.e., TMS-EEG with auditory masking and foam spacing), active-unmasked (TMS-EEG without auditory masking and foam spacing) and sham (sham TMS coil). We evaluated cortical excitability following single-pulse TMS, and cortical inhibition following a paired-pulse paradigm (long-interval cortical inhibition (LICI)). Repeated measure ANOVAs revealed significant differences in mean cortical evoked activity (CEA) of active-masked, active-unmasked, and sham conditions for both the single-pulse (F(1.76, 24.63) = 21.88, p < 0.001, η2 = 0.61) and LICI (F(1.68, 23.49) = 10.09, p < 0.001, η2 = 0.42) protocols. Furthermore, global mean field amplitude (GMFA) differed significantly across the three conditions for both single-pulse (F(1.85, 25.89) = 24.68, p < 0.001, η2 = 0.64) and LICI (F(1.8, 25.16) = 14.29, p < 0.001, η2 = 0.5). Finally, only active LICI protocols but not sham stimulation ([active-masked (0.78 ± 0.16, P < 0.0001)], [active-unmasked (0.83 ± 0.25, P < 0.01)]) resulted in significant signal inhibition. While previous findings of a significant somatosensory and auditory contribution to the evoked EEG signal are replicated by our study, an artifact attenuated cortical reactivity can reliably be measured in the TMS-EEG signal with suprathreshold stimulation of DLPFC. Artifact attenuation can be accomplished using standard procedures, and even when masked, the level of cortical reactivity is still far above what is produced by sham stimulation. Our study illustrates that TMS-EEG of DLPFC remains a valid investigational tool.

Identifying Neurophysiological Markers of Intermittent Theta Burst Stimulation in Treatment-Resistant Depression Using Transcranial Magnetic Stimulation-Electroencephalography.

BACKGROUND: Intermittent theta burst stimulation (iTBS) targeting the left dorsolateral prefrontal cortex is effective for treatment-resistant depression, but the effects of iTBS on neurophysiological markers remain unclear. Here, we indexed transcranial magnetic stimulation-electroencephalography (TMS-EEG) markers, specifically, the N45 and N100 amplitudes, at baseline and post-iTBS, comparing separated and contiguous iTBS schedules. TMS-EEG markers were also compared between iTBS responders and nonresponders. METHODS: TMS-EEG was analyzed from a triple-blind 1:1 randomized trial for treatment-resistant depression, comparing a separated (54-minute interval) and contiguous (0-minute interval) schedule of 2 × 600-pulse iTBS for 30 treatments. Participants underwent TMS-EEG over the left dorsolateral prefrontal cortex at baseline and posttreatment. One hundred fourteen participants had usable TMS-EEG at baseline, and 98 at posttreatment. TMS-evoked potential components (N45, N100) were examined via global mean field analysis. RESULTS: The N100 amplitude decreased from baseline to posttreatment, regardless of the treatment group (F1,106 = 5.20, p = .02). There were no changes in N45 amplitude in either treatment group. In responders, the N100 amplitude decreased after iTBS (F1,102 = 11.30, p = .001, pcorrected = .0004). Responders showed higher posttreatment N45 amplitude than nonresponders (F1,94 = 4.11, p = .045, pcorrected = .016). Higher baseline N100 amplitude predicted lower post-iTBS depression scores (F4,106 = 6.28, p = .00014). CONCLUSIONS: These results provide further evidence for an association between the neurophysiological effects of iTBS and treatment efficacy in treatment-resistant depression. Future studies are needed to test the predictive potential for clinical applications of TMS-EEG markers.

Pre-Stimulus Power but Not Phase Predicts Prefrontal Cortical Excitability in TMS-EEG.

The cortical response to transcranial magnetic stimulation (TMS) has notable inter-trial variability. One source of this variability can be the influence of the phase and power of pre-stimulus neuronal oscillations on single-trial TMS responses. Here, we investigate the effect of brain oscillatory activity on TMS response in 49 distinct healthy participants (64 datasets) who had received single-pulse TMS over the left dorsolateral prefrontal cortex. Across all frequency bands of theta (4-7 Hz), alpha (8-13 Hz), and beta (14-30 Hz), there was no significant effect of pre-TMS phase on single-trial cortical evoked activity. After high-powered oscillations, whether followed by a TMS pulse or not, the subsequent activity was larger than after low-powered oscillations. We further defined a measure, corrected_effect, to enable us to investigate brain responses to the TMS pulse disentangled from the power of ongoing (spontaneous) oscillations. The corrected_effect was significantly different from zero (meaningful added effect of TMS) only in theta and beta bands. Our results suggest that brain state prior to stimulation might play some role in shaping the subsequent TMS-EEG response. Specifically, our findings indicate that the power of ongoing oscillatory activity, but not phase, can influence brain responses to TMS. Aligning the TMS pulse with specific power thresholds of an EEG signal might therefore reduce variability in neurophysiological measurements and also has the potential to facilitate more robust therapeutic effects of stimulation.

Neural Correlates of the DEEPP (Anti-suicidal Response to Ketamine in Treatment-Resistant Bipolar Depression) Study: Protocol for a Pilot, Open-Label Clinical Trial.

BACKGROUND: Suicide is among the top 10 leading causes of death worldwide. Of people who died by suicide, the majority are diagnosed with depression. It is estimated that 25%-60% of people with bipolar depression (BD) will attempt suicide at least once, and 10%-15% will die by suicide. Several treatments, such as lithium, clozapine, electroconvulsive therapy, and cognitive behavioral therapy, have been shown to be effective in treating suicidality. However, these treatments can be difficult to tolerate or may take months to take effect. Ketamine, a glutamate N-methyl-D-aspartate antagonist, has been shown to have rapid antisuicidal effect and antidepressant qualities, and is thus a promising intervention to target acute suicidality in patients with BD. However, the biological mechanism underlying its therapeutic action remains poorly understood. Enhancing our understanding of underlying mechanisms of action for ketamine's effectiveness in reducing suicidality is critical to establishing biological markers of treatment response and developing tailored, personalized interventions for patients with BD. OBJECTIVE: This is an open-label clinical trial to test the safety and feasibility of repeated ketamine infusions to treat acute suicidality. The primary objective is to test the safety and feasibility of ketamine intervention. The secondary objective is to examine ketamine's potential neurophysiological mechanisms of action by assessing cortical excitation and inhibition to determine potential biomarkers of clinical response. Other objectives are to evaluate the effect of ketamine on acute suicidality and other clinical outcomes, such as depressive symptoms and quality of life, to inform a future larger trial. METHODS: This open-label clinical trial aims to test the safety and feasibility of repeated ketamine infusions in patients with BD for suicidality and to assess ketamine's neurophysiological effects. A sterile form of racemic ketamine hydrochloride will be administered over a 40-minute intravenous infusion 2 times per week on nonconsecutive days for 4 weeks (8 sessions). We will recruit 30 adults (24-65 year olds) over 2 years from an academic psychiatric hospital in Toronto, Canada. RESULTS: This study is currently ongoing and actively recruiting participants. So far, 5 participants have completed the trial, 1 is currently in active treatment, and 8 participants are on the waitlist to be screened. We anticipate initial results being available in the fall of 2023. This proposal was presented as a poster presentation at the Research to Reality Global Summit on Psychedelic-Assisted Therapies and Medicine, held in May 2022 in Toronto, Canada. CONCLUSIONS: Developing effective interventions for acute suicidality in high-risk populations such as those with BD remains a major therapeutic challenge. Ketamine is a promising treatment due to its rapid antidepressant and antisuicidal effects, but its underlying neurophysiological mechanisms of action remain unknown. TRIAL REGISTRATION: ClinicalTrials.gov NCT05177146; https://clinicaltrials.gov/ct2/show/NCT05177146. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/41013.

Low-Dose Augmentation With Buprenorphine for Treatment-Resistant Depression: A Multisite Randomized Controlled Trial With Multimodal Assessment of Target Engagement.

Background: The experimental therapeutics approach that combines a placebo-controlled clinical trial with translational neuroscience methods can provide a better understanding of both the clinical and physiological effects of pharmacotherapy. We aimed to test the efficacy and tolerability of low-dose augmentation with buprenorphine (BPN) for treatment-resistant depression, combined with multimodal assessment of target engagement. Methods: In this multisite randomized clinical trial, 85 participants ≥50 years of age with a major depressive episode that had not responded to venlafaxine extended release were randomized to augmentation with BPN or placebo for 8 weeks. The primary outcome measure was the Montgomery-Åsberg Depression Rating Scale. In addition, three linked experiments were conducted to test target engagement: 1) functional magnetic resonance imaging using the monetary incentive delay task, 2) brain positron emission tomography of healthy participants using a novel kappa opioid receptor antagonist tracer [11C]LY2795050, and 3) transcranial magnetic stimulation measure of cortical transmission after daily BPN administration. Results: The mean ± SD dosage of BPN was 0.59 ± 0.33 mg/day. There were no significant differences between the BPN and placebo groups in Montgomery-Åsberg Depression Rating Scale changes over time or adverse effects. BPN administration had minimal effects on functional magnetic resonance imaging blood oxygen level-dependent responses in regions involved in reward anticipation and response, no significant displacement of kappa opioid receptor radioligand in positron emission tomography imaging, and no significant changes in transcranial magnetic stimulation measures of inhibitory and excitatory cortical transmission. Conclusions: Our findings suggest a lack of clinical effect of low-dose BPN augmentation and lack of target engagement with this dosage and physiological probes.

Resting and TMS-EEG markers of treatment response in major depressive disorder: A systematic review.

Electroencephalography (EEG) is a non-invasive method to identify markers of treatment response in major depressive disorder (MDD). In this review, existing literature was assessed to determine how EEG markers change with different modalities of MDD treatments, and to synthesize the breadth of EEG markers used in conjunction with MDD treatments. PubMed and EMBASE were searched from 2000 to 2021 for studies reporting resting EEG (rEEG) and transcranial magnetic stimulation combined with EEG (TMS-EEG) measures in patients undergoing MDD treatments. The search yielded 966 articles, 204 underwent full-text screening, and 51 studies were included for a narrative synthesis of findings along with confidence in the evidence. In rEEG studies, non-linear quantitative algorithms such as theta cordance and theta current density show higher predictive value than traditional linear metrics. Although less abundant, TMS-EEG measures show promise for predictive markers of brain stimulation treatment response. Future focus on TMS-EEG measures may prove fruitful, given its ability to target cortical regions of interest related to MDD.

Effect of high frequency versus theta-burst repetitive transcranial magnetic stimulation on suicidality in patients with treatment-resistant depression.

OBJECTIVE: To investigate the effect of 10 Hz repetitive transcranial magnetic stimulation (rTMS) and intermittent theta-burst stimulation (iTBS) on suicidality in patients with treatment-resistant depression (TRD). METHODS: We used data from a three-site randomized clinical trial comparing 10 Hz rTMS and iTBS applied to the left dorsolateral prefrontal cortex (DLPFC) in patients with TRD. We compared the effect of 10Hz rTMS and iTBS on suicidality as measured by the suicide item of the Hamilton Depression Rating Scale 17-item (HDRS-17). RESULTS: Suicidality remitted in 71 (43.7%) participants randomized to 10Hz stimulation and 91 (49.1%) participants randomized to iTBS, without a significant difference between the proportions in the two groups (Χ2  = 0.674, df = 1, p = 0.4117). There was a significant correlation between change in suicidality and change in depression severity for both modalities (10 Hz, Pearson's r = 0.564; iTBS, Pearson's r = 0.502), with a significantly larger decrease in depression severity for those in whom suicidality remitted compared to those in whom it did not (t = 10.912, df = 276.8, p < 0.001). CONCLUSIONS: Both 10 Hz and iTBS rTMS were effective in reducing suicidality in TRD. Future trials of iTBS for depression should include discrete measures of suicidality.

The Effect of Repetitive Transcranial Magnetic Stimulation on Suicidal Ideation in Treatment-Resistant Depression: A Meta-Analysis.

Objective: To quantitatively synthesize the literature on the effects of repetitive transcranial magnetic stimulation (rTMS) on suicidal ideation (SI) in patients with treatment-resistant depression.Data Sources: A literature search was conducted using PubMed, SCOPUS, Ovid, MEDLINE, Embase, and Web of Science from inception to January 11, 2021, for the keywords repetitive transcranial magnetic stimulation, suicidal ideation, suicidality, treatment-resistant depression, refractory depression, transcranial magnetic stimulation, and brain stimulation.Study Selection: A total of 16 publications were eligible for inclusion. Studies were included that investigated the effects of rTMS in adolescents and/or adults 16 years or older diagnosed with unipolar or bipolar depression with suicidal ideation data before and after rTMS intervention.Data Extraction: Data were extracted and managed using Covidence. Extracted data included authors, publication year, country of origin, study design, patient demographics, primary diagnosis, comorbidities, mean age, outcome assessment instruments, detailed stimulation parameters, sham control procedures, and any serious adverse events related to SI.Results: A quantitative analysis of effect size using Hedges g was calculated for both randomized controlled trials and all other uncontrolled trials. We found a decrease in SI scores in randomized controlled trials (g = 0.158, 95% confidence interval [CI] = -0.078 to 0.393, P = .191), although the effect was not significant. There was a significant decrease in suicidal ideation scores for uncontrolled trials (g = 0.692, 95% CI = 0.463 to 0.922, P < .001).Conclusions: Our findings suggest that rTMS may be an effective treatment for SI in individuals with treatment-resistant depression, although further investigation is warranted.

The Safety, Clinical, and Neurophysiological Effects of Intranasal Ketamine in Patients Who Do Not Respond to Electroconvulsive Therapy: Protocol for a Pilot, Open-Label Clinical Trial.

BACKGROUND: Major depressive disorder is among the most disabling illnesses worldwide, with a lifetime prevalence of 16.2%. Research suggests that 20% to 40% of patients with depression do not respond to pharmacotherapy, developing treatment-resistant depression. Electroconvulsive therapy is the gold standard for treating individuals with treatment-resistant depression, with remission rates of approximately 75% to 90%. However, 10% to 25% of patients do not respond to electroconvulsive therapy, and many are unable to tolerate it due to the side effects. Both groups are considered to be patients who do not respond to electroconvulsive therapy, because both groups continue to exhibit symptoms of severe depression, have a limited number of treatment options available, and are in need of rapid treatment. Ketamine, an N-methyl-D-aspartate receptor antagonist, has been shown to exert rapid antidepressant effects in patients with treatment-resistant depression when administered in subanesthetic doses through 40-minute intravenous infusions. Recently, a ketamine compound, esketamine (Spravato), that is administered through the intranasal route received regulatory approval by the US Food and Drug Administration and Health Canada to treat depression. However, esketamine is challenging to access due to high costs and limited availability. Racemic ketamine (rketamine) is cheap and easy to access; however, the effects in patients who have not responded to electroconvulsive therapy have yet to be understood or tested. This study will use transcranial magnetic stimulation to study mechanisms of human brain cortical physiology at the systemic level to identify neurobiomarkers of response. OBJECTIVE: The objective of this open-label pilot clinical trial is to test the feasibility and safety of intranasal ketamine in patients who have not responded to electroconvulsive therapy. The primary outcome is to determine the feasibility of a larger randomized controlled trial to test the efficacy of intranasal ketamine for patients who have not responded to electroconvulsive therapy for clinical indicators in unipolar depression. The secondary outcome is to determine the preliminary effects of an intervention on clinical outcomes, such as depressive symptoms, suicidal ideation, and quality of living. The third outcome is to explore neurophysiological changes as measured by transcranial magnetic stimulation electromyography and electroencephalography to measure changes in cortical excitability as potential predictors of clinical response. METHODS: A sterile solution of racemic ketamine hydrochloride will be administered twice per week for 4 weeks (8 sessions) intranasally to patients with treatment-resistant depression who did not respond to or could not tolerate an acute course of electroconvulsive therapy. We will recruit 25 adults (24-65 years old) over the course of 2 years from an academic psychiatric hospital in Toronto, Canada. RESULTS: This study has received ethics approval, and funding has been secured. The study is currently active. CONCLUSIONS: This is the first study to test repeated doses of intranasal rketamine in patients who have not responded to electroconvulsive therapy for depression. Results from this study will (1) inform the development of a larger adequately powered randomized controlled trial to test the efficacy of intranasal ketamine for depression and (2) determine potential neurophysiological markers of clinical response. TRIAL REGISTRATION: Clinical Trials.gov NCT05137938; http://clinicaltrials.gov/ct2/show/NCT05137938. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/30163.

Continuation Magnetic Seizure Therapy for Treatment-Resistant Unipolar or Bipolar Depression.

Objective: Electroconvulsive therapy (ECT) is highly effective for treatment-resistant depression (TRD) but may be associated with adverse cognitive effects. Magnetic seizure therapy (MST) is a promising alternative convulsive treatment with a safer cognitive profile. Although there is emerging evidence for the efficacy of MST for TRD as an acute treatment, there are no published studies of continuation MST for the prevention of relapse.Methods: Patients with TRD with a DSM-IV diagnosis of major depressive disorder or bipolar disorder who met response criteria after acute MST were offered continuation MST in a prospective, open-label trial between February 2012 and June 2019. They received 12 continuation MST sessions with decreasing frequency over the course of 6 months, with additional booster sessions if their depression symptoms started to worsen. The primary outcome was relapse of depression or psychiatric hospitalization. Secondary outcomes included relapse of suicidal ideation and neurocognitive outcomes.Results: Thirty participants completing at least one assessment during continuation MST were included in the analysis; 10 (33.3%) relapsed, with no significant differences in survival distributions between unipolar and bipolar groups (χ2 = 0.3, P = .58). Mean (SD) survival time was 18.6 (1.6) weeks. All 17 participants who achieved resolution of baseline suicidality after acute MST remained free of suicidality during the continuation phase. Except for improvement in verbal fluency, neurocognitive test scores did not change during continuation MST.Conclusions: During 6 months of continuation MST, two-thirds of participants sustained improvements in depressive symptoms without any adverse cognitive effects. Future studies of continuation MST are warranted, particularly in comparison to ECT.Trial Registration: ClinicalTrials.gov identifier: NCT01596608.

A randomized sham controlled comparison of once vs twice-daily intermittent theta burst stimulation in depression: A Canadian rTMS treatment and biomarker network in depression (CARTBIND) study.

BACKGROUND: Intermittent theta burst stimulation (iTBS) is a newer form of repetitive transcranial magnetic stimulation (rTMS) for patients with treatment resistant depression (TRD). Applying multiple daily iTBS sessions may enable patients to achieve remission more rapidly. OBJECTIVE: We compared the efficacy and tolerability of a twice-daily versus once-daily iTBS protocol in patients with TRD. We hypothesized that twice-daily iTBS would result in a greater improvement in depression scores compared to once-daily iTBS. METHODS: 208 participants (131 females) with TRD were randomized to receive either iTBS (600 pulses) delivered twice-daily with a 54-min interval between treatments or once-daily (1200 pulses) with 1 sham treatment with the same interval between treatments, to ensure equal levels of daily therapeutic contact and blinding of patients and raters. The primary outcome measure was change in depression scores on the Hamilton Rating Scale for Depression (HRSD-17) after 10 days of treatment and 30 days of treatments. RESULTS: HRSD-17 scores improved in both the twice-daily and once-daily iTBS groups; however, these improvements did not significantly differ between the two groups at either the 10-day or 30-day timepoints. Response and remission rates were low (<10%) in both groups after 10 days and consistent with prior reports at 30 days; these rates did not differ between the treatment groups. CONCLUSIONS: These results suggest that twice-daily iTBS does not accelerate response to iTBS and is not different from once-daily treatment in terms of improving depressive symptoms in patients with TRD. Clinicaltrials.gov ID: NCT02729792 (https://clinicaltrials.gov/ct2/show/NCT02729792).

Neurophysiological effects of repetitive transcranial magnetic stimulation (rTMS) in treatment resistant depression.

OBJECTIVE: Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment resistant depression (TRD), but little is known about rTMS' effects on neurophysiological markers. We previously identified neurophysiological markers in depression (N45 and N100) of GABA receptor mediated inhibition. Here, we indexed TMS-electroencephalographic (TMS-EEG) effects of rTMS. METHODS: TMS-EEG data was analyzed from a double blind 2:1 randomized active (10 Hz left/bilateral):sham rTMS TRD trial. Participants underwent TMS-EEG over left dorsolateral prefrontal cortex (DLPFC) before and after 6 weeks of rTMS. 30 had useable datasets. TMS-evoked potentials (TEP) and components (N45, N100, P60) were examined with global mean field analysis (GMFA) and locally in DLPFC regions of interest. RESULTS: The N45 amplitude differed between active and sham groups over time, N100 amplitude did not. N45 (t = 2.975, p = 0.007) and N100 amplitudes (t = 2.177, p = 0.042) decreased after active rTMS, demonstrating alterations in cortical inhibition. TEP amplitudes decreased after active rTMS in left (t = 4.887, p < 0.001) and right DLPFC (t = 4.403, p < 0.001) not sham rTMS, demonstrating alterations in cortical excitability. CONCLUSIONS: Our results provide important new knowledge regarding rTMS effects on TMS-EEG measures in TRD, suggesting rTMS reduces neurophysiological markers of inhibition and excitability. SIGNIFICANCE: These findings uncover potentially important neurophysiological mechanisms of rTMS action.

Differentiating transcranial magnetic stimulation cortical and auditory responses via single pulse and paired pulse protocols: A TMS-EEG study.

OBJECTIVE: We measured the neurophysiological responses of both active and sham transcranial magnetic stimulation (TMS) for both single pulse (SP) and paired pulse (PP; long interval cortical inhibition (LICI)) paradigms using TMS-EEG (electroencephalography). METHODS: Nineteen healthy subjects received active and sham (coil 90° tilted and touching the scalp) SP and PP TMS over the left dorsolateral prefrontal cortex (DLPFC). We measured excitability through SP TMS and inhibition (i.e., cortical inhibition (CI)) through PP TMS. RESULTS: Cortical excitability indexed by area under the curve (AUC(25-275ms)) was significantly higher in the active compared to sham stimulation (F(1,18) = 43.737, p < 0.001, η2 = 0.708). Moreover, the amplitude of N100-P200 complex was significantly larger (F(1,18) = 9.118, p < 0.01, η2 = 0.336) with active stimulation (10.38 ± 9.576 µV) compared to sham (4.295 ± 2.323 µV). Significant interaction effects were also observed between active and sham stimulation for both the SP and PP (i.e., LICI) cortical responses. Finally, only active stimulation (CI = 0.64 ± 0.23, p < 0.001) resulted in significant cortical inhibition. CONCLUSION: The significant differences between active and sham stimulation in both excitatory and inhibitory neurophysiological responses showed that active stimulation elicits responses from the cortex that are different from the non-specific effects of sham stimulation. SIGNIFICANCE: Our study reaffirms that TMS-EEG represents an effective tool to evaluate cortical neurophysiology with high fidelity.