Functional changes in sleep-related arousal after ketamine administration in individuals with treatment-resistant depression.

The glutamatergic modulator ketamine is associated with changes in sleep, depression, and suicidal ideation (SI). This study sought to evaluate differences in arousal-related sleep metrics between 36 individuals with treatment-resistant major depression (TRD) and 25 healthy volunteers (HVs). It also sought to determine whether ketamine normalizes arousal in individuals with TRD and whether ketamine's effects on arousal mediate its antidepressant and anti-SI effects. This was a secondary analysis of a biomarker-focused, randomized, double-blind, crossover trial of ketamine (0.5 mg/kg) compared to saline placebo. Polysomnography (PSG) studies were conducted one day before and one day after ketamine/placebo infusions. Sleep arousal was measured using spectral power functions over time including alpha (quiet wakefulness), beta (alert wakefulness), and delta (deep sleep) power, as well as macroarchitecture variables, including wakefulness after sleep onset (WASO), total sleep time (TST), rapid eye movement (REM) latency, and Post-Sleep Onset Sleep Efficiency (PSOSE). At baseline, diagnostic differences in sleep macroarchitecture included lower TST (p = 0.006) and shorter REM latency (p = 0.04) in the TRD versus HV group. Ketamine's temporal dynamic effects (relative to placebo) in TRD included increased delta power earlier in the night and increased alpha and delta power later in the night. However, there were no significant diagnostic differences in temporal patterns of alpha, beta, or delta power, no ketamine effects on sleep macroarchitecture arousal metrics, and no mediation effects of sleep variables on ketamine's antidepressant or anti-SI effects. These results highlight the role of sleep-related variables as part of the systemic neurobiological changes initiated after ketamine administration. Clinical Trials Identifier: NCT00088699.

Alcohol and substance use in older adults with treatment-resistant depression.

INTRODUCTION: Alcohol and substance use are increasing in older adults, many of whom have depression, and treatment in this context may be more hazardous. We assessed alcohol and other substance use patterns in older adults with treatment-resistant depression (TRD). We examined patient characteristics associated with higher alcohol consumption and examined the moderating effect of alcohol on the association between clinical variables and falls during antidepressant treatment. METHODS: This secondary and exploratory analysis used baseline clinical data and data on falls during treatment from a large randomized antidepressant trial in older adults with TRD (the OPTIMUM trial). Multivariable ordinal logistic regression was used to identify variables associated with higher alcohol use. An interaction model was used to evaluate the moderating effect of alcohol on falls during treatment. RESULTS: Of 687 participants, 51% acknowledged using alcohol: 10% were hazardous drinkers (AUDIT-10 score ≥5) and 41% were low-risk drinkers (score 1-4). Benzodiazepine use was seen in 24% of all participants and in 21% of drinkers. Use of other substances (mostly cannabis) was associated with alcohol consumption: it was seen in 5%, 9%, and 15% of abstainers, low-risk drinkers, and hazardous drinkers, respectively. Unexpectedly, use of other substances predicted increased risk of falls during antidepressant treatment only in abstainers. CONCLUSIONS: One-half of older adults with TRD in this study acknowledged using alcohol. Use of alcohol concurrent with benzodiazepine and other substances was common. Risks-such as falls-of using alcohol and other substances during antidepressant treatment needs further study.

Recurrent Serotonin Syndrome After Ketamine-assisted Electroconvulsive Therapy: A Case Report and Review of the Literature.

Serotonin (5-HT) syndrome (SS) consists of changes in mental status as well as autonomic and neuromuscular changes. Though not well understood, serotonergic pathways have been implicated in the mechanism of action of electroconvulsive therapy (ECT). Ketamine has been used as an induction agent in ECT and as therapy for treatment-resistant depression. Utilizing a case report and literature review, we explored the underlying serotonergic mechanisms of ECT and ketamine by which a syndrome of serotonin toxicity may be precipitated. We describe the case of a 72-year-old woman who developed recurrent SS on 2 occasions in similar circumstances involving the administration of ketamine for ECT. In our literature review, we found 5 cases in which SS was associated with ECT and 1 case linking ketamine to SS. There is emerging evidence that the mechanism of ECT involves 5-HT1A and 5-HT2A receptors, the same receptors that are involved in SS. ECT can transiently increase the permeability of the blood-brain barrier, leading to increased levels of antidepressants in the brain. ECT can, therefore, enhance 5-HT transmission and the likelihood of SS in the presence of serotonergic agents. The effect of ketamine on 5-HT transmission is mediated by the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor. Ketamine increases α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid activity in the medial prefrontal cortex, which leads to downstream 5-HT release through glutamate. Through this mechanism, ketamine can increase 5-HT transmission, leading to SS. To our knowledge, this is the only case report of recurrent SS with concurrent use of ECT and ketamine. As ketamine is frequently used in ECT and many patients undergoing ECT are on serotonergic medications, it is important to recognize ketamine as a potential risk factor for SS. There is no evidence for added efficacy when combining ECT and ketamine. Thus, one should proceed with caution when combining these treatments. The burgeoning use of ketamine in ambulatory settings makes it necessary to elucidate the risks, which we discuss further. More research is needed into the mechanisms of ketamine and ECT, specifically how the combination of these treatments influence 5-HT levels.

Increasing the bioavailability of oral esketamine by a single dose of cobicistat: A case study.

BACKGROUND: Intranasal esketamine is an approved drug for treatment­resistant depression (TRD); however, it is costly and may result in specific adverse effects. In this single case study, we explored if oral esketamine can be a suitable alternative. METHODS: In collaboration with a 39­year­old female with TRD, we compared plasma concentration curves of intranasal (84 mg) and oral (1, 2 and 4 mg/kg) esketamine. Because oral esketamine has a relatively low bioavailability, it results in a different ratio between esketamine and its primary metabolite noresketamine. To increase the bioavailability of oral esketamine, we co­administered a single dose of the cytochrome P­450 (CYP) 3A4 inhibitor cobicistat (150 mg). RESULTS: For all doses administered, oral esketamine resulted in lower esketamine but higher noresketamine peak plasma concentrations compared with intranasal treatment. Using oral esketamine it was not possible to generate a similar esketamine plasma concentration curve as with the intranasal treatment, except when combined with cobicistat (esketamine 2 mg/kg plus cobicistat 150 mg). CONCLUSIONS: Our findings demonstrate that cobicistat effectively increases the bioavailability of oral esketamine. Further research is required in a larger population, especially to investigate the clinical benefit of cobicistat as a booster drug for oral esketamine.

Effects of ebselen addition on emotional processing and brain neurochemistry in depressed patients unresponsive to antidepressant medication.

Lithium is an effective augmenting agent for depressed patients with inadequate response to standard antidepressant therapy, but numerous adverse effects limit its use. We previously reported that a lithium-mimetic agent, ebselen, promoted a positive emotional bias-an indicator of potential antidepressant activity in healthy participants. We therefore aimed to investigate the effects of short-term ebselen treatment on emotional processing and brain neurochemistry in depressed patients with inadequate response to standard antidepressants. We conducted a double-blind, placebo-controlled 7-day experimental medicine study in 51 patients with major depressive disorder who were currently taking antidepressants but had an inadequate response to treatment. Participants received either ebselen 600 mg twice daily for seven days or identical matching placebo. An emotional testing battery, magnetic resonance spectroscopy and depression and anxiety rating scales were conducted at baseline and after seven days of treatment. Ebselen did not increase the recognition of positive facial expressions in the depressed patient group. However, ebselen increased the response bias towards fear emotion in the signal detection measurement. In the anterior cingulate cortex, ebselen significantly reduced the concentrations of inositol and Glx (glutamate+glutamine). We found no significant differences in depression and anxiety rating scales between visits. Our study did not find any positive shift in emotional bias in depressed patients with an inadequate response to antidepressant medication. We confirmed the ability of ebselen to lower inositol and Glx in the anterior cingulate cortex. These latter effects are probably mediated through inhibition of inositol monophosphatase and glutaminase respectively.

Rapid and sustained antidepressant effects of intravenous ketamine in treatment-resistant major depressive disorder and suicidal ideation: a randomized clinical trial.

BACKGROUND: Major depressive disorder (MDD) is the most disabling and burdensome mental disorder, negatively affecting an individual's quality of life and daily functioning. the current study was conducted with the aim of investigating the clinical effects of intravenous ketamine on symptoms of MDD and suicidal ideation. METHODS: The current randomized clinical trial was carried out on 64 patients diagnosed with treatment-resistant major depressive disorder between April and August 2022. The participants were randomly assigned to two groups: the intervention group received a dose of 0.5 mg/kg of ketamine, while the control group received normal saline. The Montgomery-Asberg Depression Scale and Beck's Suicidal Ideation Scale were utilized to assess depression and suicidal ideation, respectively. RESULTS: One hour after the administration of ketamine treatment, there was a notable and significant improvement in both depression symptoms (35.16 ± 8.13 vs. 14.90 ± 10.09) and suicidal ideation (6.74 ± 6.67 vs. 0.42 ± 1.52). Moreover, there were statistically significant differences in depression scores between the two groups at one hour, four hours, one day, three days, one week, one month, and two months after the administration of ketamine (p-value < 0.001). However, ketamine recipients frequently experienced side effects such as increased heart rate, headache, dizziness, and dissociative syndrome symptoms. CONCLUSION: The observed rapid onset of action and sustained effect demonstrate the potential of ketamine to provide relief from depressive symptoms in a shorter timeframe compared to traditional treatment approaches. These findings contribute to the growing body of evidence supporting the use of ketamine as a valuable therapeutic option for patients with treatment-resistant depression. IRCT REGISTRATION: IRCT registration number: IRCT20210806052096N1; IRCT URL: https://www.irct.ir/trial/62243 ; Ethical code: IR.ZUMS.REC.1400.150; Registration date: 2022-04-09.

Efficacy of addition of the anti-inflammatory, IV glutathione to standard ketamine IV therapy in major depressive disorder.

Ketamine, a N-methyl-D-aspartate (NMDA) antagonist, is used for treatment-resistant depression (TRD). Recent studies have shown that there are increased levels of pro-inflammatory cytokines in individuals with major depressive disorder (MDD) and those with higher levels of oxidative stress markers have a decreased or null response to conventional antidepressants. Glutathione (GSH) as an antioxidant adjuvant to ketamine has not been well studied. This double-blind study with 30 patients divided into 2 groups of 15 each, aimed to determine if GSH, added to standard ketamine infusion (GSH+K), rendered better outcomes in MDD patients versus patients receiving ketamine infusions with a normal saline placebo (K+NS). There were significant drops in BDI-II scores from day 1 to day 14, PHQ- scores from day 1 to day 14 and PHQ-9 scores day 14 to day 28, suggesting the overall treatment was effective. There were no statistically significant differences between the groups over time. However, a sustained improvement in depressive symptoms was observed for 14 days post-infusion in both groups.

Investigating Resistance to Antidepressants in Animal Models.

Major depressive disorder is one of the most prevalent psychiatric diseases, and up to 30-40% of patients remain symptomatic despite treatment. Novel therapies are sorely needed, and animal models may be used to elucidate fundamental neurobiological processes that contribute to human disease states. We conducted a systematic review of current preclinical approaches to investigating treatment resistance with the goal of describing a path forward for improving our understanding of treatment resistant depression. We conducted a broad literature search to identify studies relevant to the preclinical investigation of treatment resistant depression. We followed PRISMA (Preferred Reporting Items for Systemic Reviews and Meta-Analyses) guidelines and included all relevant studies. We identified 467 studies in our initial search. Of these studies, we included 69 in our systematic review after applying our inclusion/exclusion criteria. We identified 10 broad strategies for investigating treatment resistance in animal models. Stress hormone administration was the most commonly used model, and the most common behavioral test was the forced swim test. We systematically identified and reviewed current approaches for gaining insight into the neurobiology underlying treatment resistant depression using animal models. Each approach has its advantages and disadvantages, but all require careful consideration of their potential limitations regarding therapeutic translation. An enhanced understanding of treatment resistant depression is sorely needed given the burden of disease and lack of effective therapies.

Evaluation of New Approaches to Depression Treatment Using an Animal Model of Pharmacoresistant Depression.

Depression is emerging as the predominant psychiatric disorder globally. Despite the wide availability of antidepressants, up to 30% of patients exhibit poor response to treatment, falling into the category of treatment-resistant depression (TRD). This underscores the need for the exploration of novel therapeutic options. Our work aims to study the effect of chronic administration of the pyridoindole derivative SMe1EC2M3, a triple reuptake inhibitor, and the combination of zoletil and venlafaxine under conditions of stress induced by a 4-week chronic mild stress (CMS) procedure in Wistar-Kyoto male rats as an animal model of TRD. Therefore, we investigated the possible effect of the selected compounds in four experimental groups, i.e., stress + vehicle, stress + venlafaxine, stress + zoletil + venlafaxine and stress + SMe1EC2M3. The following variables were assessed: anhedonia in sucrose preference test (SPT), spontaneous locomotion and exploration in open field test (OF), anxiety-like behavior in elevated plus maze test (EPM), motivation and depressive-like behavior in forced swim test (FST) and nociception in tail flick test. We also evaluated cognition, particularly recognition memory, in the novel object recognition test (NOR). Sucrose preference was significantly increased in the SMe1EC2M3 group (p < 0.05) in comparison with the venlafaxine animals. In the OF, we observed a significantly higher number of entries into both the central and peripheral zones in the venlafaxine (p < 0.05 central zone; p ≤ 0.05 periphery zone) and SMe1EC2M3 (p < 0.05 central zone; p < 0.05 periphery zone) groups compared to the venlafaxine + zoletil group. SMe1EC2M3 was able to significantly increase the time of climbing in FST (p < 0.05) in comparison with the venlafaxine and control groups. The NOR test revealed a significantly higher discrimination ratio in the SMe1EC2M3 group (p < 0.05) compared to the control and venlafaxine groups. Analyses of the tail flick test showed a significant increase in reaction time to painful stimuli in the SMe1EC2M3 group (p < 0.05) in comparison to both the control and venlafaxine groups. Our findings suggest that SMe1EC2M3 has the potential to ameliorate some behavioral changes associated with TRD, and the venlafaxine + zoletil combination treatment was not a promising treatment alternative in the animal model of TRD.

Optimally combining transcranial magnetic stimulation with antidepressants in major depressive disorder: A systematic review and Meta-analysis.

There is a critical knowledge gap in optimally combining transcranial magnetic stimulation (TMS) and antidepressants to treat patients with major depressive disorder (MDD). TMS is effective in treating MDD in patients who have failed at least one antidepressant trial, with accelerated protocols showing faster remission in treatment-resistant depression (TRD). Although clinicians routinely augment antidepressants with TMS, there is a knowledge gap in stopping versus continuing antidepressants or the dosing strategies when starting or tapering TMS. These considerations are important when considering maintenance TMS (delivered alone or in combination with suitable antidepressants) to maintain remission in MDD after the index course of TMS. As the first step towards filling this knowledge gap, we reviewed randomized controlled trials (RCTs) and open-label trials from 2 databases (PubMed/Medline and EMBASE) that compared active TMS combined with a pre-specified antidepressant dosed in the same manner for adults with MDD versus sham TMS combined with the same antidepressant as in the active arm. All studies were published between January 1, 2000, and December 31, 2023. We excluded case reports, case series, and clinical studies that augmented TMS with antidepressants and vice versa. We found 10 RCTs (n = 654 participants) and performed a meta-analysis. This showed active TMS combined with pre-specified antidepressants had greater efficacy for MDD treatment than sham TMS combined with the same antidepressants as in the active arm (Hedge's g = 1; 95 % CI [0.27, 1.73]). The review and meta-analysis indicate greater short-term efficacy in combining antidepressants with TMS from the get-go in MDD. Given the increasing role of accelerated TMS protocols in expediting remission in MDD and the results of our meta-analysis, we advocate for RCTs examining the short-term and long-term effects of various antidepressant classes on these TMS protocols in MDD. This can also optimize and individualize maintenance TMS protocols to prevent relapse in MDD.

The association between ketamine and esketamine with alcohol and substance misuse: Reports to the Food and Drug Administration adverse event reporting system (FAERS).

INTRODUCTION: Ketamine and esketamine have been proven to be effective in treating adults with treatment resistant depression (TRD). Preliminary evidence indicates that, when combined with behavioral and psychological interventions, both agents may offer benefits for individuals with substance use disorder (SUD) and alcohol use disorder (AUD). Notwithstanding, concerns have been raised as to whether either or both agents are associated with abuse and/or gateway activity. METHODS: Herein, we evaluate disproportionate reporting expressed as reporting odds ratios (ROR) for esketamine and ketamine. The outcomes of interest include alcohol problem, alcoholism, alcohol abuse, substance dependence, SUD, substance abuse, drug dependence, drug use disorder and drug abuse as codified by the Medical Dictionary for Regulatory Activities (MedDRA) within the FAERS. The IC025 values were significant for ketamine in cases of alcohol abuse (0.28), substance dependence (1.88), substance use disorder (0.996), substance abuse (0.61), drug dependence (0.56), drug use disorder (1.17) and drug abuse (1.22). Additionally, oxycontin showed significant IC025 values for substance dependence (0.067), substance use disorder (0.094), substance abuse (0.035), and drug dependence (0.27). RESULTS: We observed significant increases in the reporting odds ratios (RORs) for ketamine with respect to various outcomes: alcohol abuse (ROR 2.84, 95 % CI 1.53-5.28; p = 0.0010), substance dependence (ROR 18.72, 95 % CI 8.49-41.30; p ≤ 0.0001), SUD (ROR 11.40, 95 % CI 4.24-30.65; p ≤ 0.0001), substance abuse (ROR 2.29, 95 % CI 1.73-3.04; p ≤ 0.0001), drug dependence (ROR 1.99, 95 % CI 1.64-2.42; p ≤ 0.0001), drug use disorder (ROR 4.50, 2.94-6.88; p ≤ 0.0001) and drug abuse (ROR 3.72, 3.36-4.12; p ≤ 0.0001). For esketamine, we observed that the ROR was significantly reduced for substance abuse (ROR 0.37, 95 % CI 0.22-0.63; p = 0.0003), drug dependence (ROR 0.13, 95 % CI 0.076-0.23; p ≤ 0.0001) and drug abuse (ROR 0.048, 95 % CI 0.030-0.078; p ≤ 0.0001). To our knowledge, this is the first report of spontaneous adverse events related to these outcomes of interest in the FAERS. CONCLUSION: Mixed RORs were observed across aspects of SUD and AUD for both ketamine and esketamine. Due to limitations in the FAERS, establishing causal links between new onset alcohol and substance misuse with either agent remains inconclusive. Possible beneficial effects on measures of SUD and AUD were observed. It is currently unclear, but possible, whether both agents have differential ameliorative effects across dimensions of SUD and AUD, which is a focus of ongoing research.

National trends and correlates of treatment resistance in major depressive episode and associated suicidal ideation and behaviors among adults in the United States.

OBJECTIVE: To examine recent 12-year trends in prevalence of suicidal ideation and behaviors (SIBs) among US adults experiencing a past-year treatment-resistant depression (TRD). METHODS: Using data from the National Survey of Drug Use and Health, we estimated the annual percentage of individuals aged ≥18 with TRD who reported past-year SIBs, and estimated linear trends adjusting for potentially confounding factors from 2009 to 2020. RESULTS: Of estimated 237.5 million US adults, 7.1 % met diagnostic criteria for a past-year major depressive episode (MDE) between 2009 and 2020. Of these, 9.7 % met criteria for TRD. The proportion reporting past-year suicidal ideation in TRD ranged from 39.5 % (95 % confidence interval [CI], 32.1-47.3 %) in 2009-2010 to 43.4 % (95 % CI, 36.7-503 %) in 2019-2020, with an average annual percent change (AAPC) of 1.3 % (95 % CI, -0.7 % to 3.3 %). The prevalence of past-year suicide attempts in TRD was 7.3 % across the study period (AAPC, 0.1 %; 95 % CI, -4.3 % to 4.7 %). Past-year SIBs were significantly associated with an increased likelihood of meeting criteria for TRD among adults with MDE (adjusted odds ratio [AOR], 1.53; 95 % CI, 1.35-1.75 for suicidal ideation; AOR, 2.17; 95 % CI, 1.79-2.62 for suicide attempts). No significant differences were observed between 2019 and 2020, reflecting the COVID-19 pandemic. CONCLUSION: Among individuals with TRD, proportions of SIBs are high. These findings underscore an urgent need for suicide prevention efforts in this high-risk population, including preventive services across diverse settings and accessibility to evidence-based pharmacological and non-pharmacological interventions.

Propofol enhancement of slow wave sleep to target the nexus of geriatric depression and cognitive dysfunction: protocol for a phase I open label trial.

INTRODUCTION: Late-life treatment-resistant depression (LL-TRD) is common and increases risk for accelerated ageing and cognitive decline. Impaired sleep is common in LL-TRD and is a risk factor for cognitive decline. Slow wave sleep (SWS) has been implicated in key processes including synaptic plasticity and memory. A deficiency in SWS may be a core component of depression pathophysiology. The anaesthetic propofol can induce electroencephalographic (EEG) slow waves that resemble SWS. Propofol may enhance SWS and oral antidepressant therapy, but relationships are unclear. We hypothesise that propofol infusions will enhance SWS and improve depression in older adults with LL-TRD. This hypothesis has been supported by a recent small case series. METHODS AND ANALYSIS: SWIPED (Slow Wave Induction by Propofol to Eliminate Depression) phase I is an ongoing open-label, single-arm trial that assesses the safety and feasibility of using propofol to enhance SWS in older adults with LL-TRD. The study is enrolling 15 English-speaking adults over age 60 with LL-TRD. Participants will receive two propofol infusions 2-6 days apart. Propofol infusions are individually titrated to maximise the expression of EEG slow waves. Preinfusion and postinfusion sleep architecture are evaluated through at-home overnight EEG recordings acquired using a wireless headband equipped with dry electrodes. Sleep EEG recordings are scored manually. Key EEG measures include sleep slow wave activity, SWS duration and delta sleep ratio. Longitudinal changes in depression, suicidality and anhedonia are assessed. Assessments are performed prior to the first infusion and up to 10 weeks after the second infusion. Cognitive ability is assessed at enrolment and approximately 3 weeks after the second infusion. ETHICS AND DISSEMINATION: The study was approved by the Washington University Human Research Protection Office. Recruitment began in November 2022. Dissemination plans include presentations at scientific conferences, peer-reviewed publications and mass media. Positive results will lead to a larger phase II randomised placebo-controlled trial. TRIAL REGISTRATION NUMBER: NCT04680910.

Depression: Managing Resistance and Partial Response to Treatment.

Treatment-resistant depression is defined as absence of remission despite trials of two or more antidepressant medications and can occur in up to 31% of patients with major depressive disorder. Partial response to treatment is defined as less than 50% reduction in depression-rating scores. Before diagnosing treatment-resistant depression or partial response to treatment, adherence to adequate doses and duration of medications should be confirmed. Management strategies include adding psychotherapy, switching antidepressant medication class, or augmenting with additional medications. Current guidelines recommend augmentation with a second-generation antidepressant, an atypical antipsychotic, tricyclic antidepressants, lithium, or a triiodothyronine medication as pharmacologic options. Ketamine and esketamine can also be used as augmentation for treatment-resistant depression and may help reduce suicidal ideation. Electroconvulsive therapy and repetitive transcranial magnetic stimulation may be effective. Pharmacogenetic testing has limited evidence and is not recommended. Nonpharmacologic therapies include psychotherapy, exercise, and focused dietary changes.

Barriers to Esketamine Nasal Spray Treatment Among Adults With Treatment-Resistant Depression.

Background: Under a risk evaluation and mitigation strategy program, esketamine nasal spray CIII requires self administration at a certified treatment center. Our objective was to identify factors associated with esketamine initiation and continuation.Methods: A retrospective observational cohort study was conducted among US adults who met treatment-resistant depression (TRD) criteria. Cases (n = 966) initiated esketamine between October 11, 2019, and February 28, 2022, and were compared to controls (n = 39,219) with TRD but no esketamine use. Outcomes included initiation, induction (8 administrations within 45 days), and interruptions (30-day treatment gap). Comorbid psychiatric conditions were identified using International Classification of Diseases, Tenth Revision, Clinical Modification, codes.Results: Cases resided significantly closer to treatment centers (8.9 vs 20.3 miles). Compared to 0-9 miles, initiation rate decreased by 11.9%, 50.8%, 68.1%, 75.9%, and 92.8% for individuals residing 10-19, 20-29, 30-39, 40-49, and 50+ miles from a center. After adjustment, factors associated with increased likelihood of initiation were posttraumatic stress disorder, major depressive disorder with suicidal ideation, and male sex, while increasing distance, substance use disorder, Medicaid, Charlson Comorbidity Index (CCI), and older age were associated with lower likelihood. Factors associated with lower likelihood of completing induction were Medicaid, low socioeconomic status (SES), CCI, and Hispanic communities. Factors associated with increased likelihood of interruption were alcohol use disorder, distance, and minority communities, while generalized anxiety disorder and Medicaid were associated with lower likelihood.Conclusions: Travel distance, insurance, low SES, and minority communities are potential barriers to treatment. Alternative care models may be needed to ensure adequate access to care.J Clin Psychiatry 2024;85(2):23m15102.

Protocol for a randomised controlled trial of ketamine versus ketamine and behavioural activation therapy for adults with treatment-resistant depression in the community.

INTRODUCTION: Although short-term benefits follow parenteral ketamine for treatment-resistant major depressive disorder (TR-MDD), there are challenges that prevent routine use of ketamine by clinicians. These include acute dissociative effects of parenteral ketamine, high relapse rates following ketamine dosing and the uncertain role of psychotherapy. This randomised controlled trial (RCT) seeks to establish the feasibility of evaluating repeated oral doses of ketamine and behavioural activation therapy (BAT), compared with ketamine treatment alone, for TR-MDD. We also aim to compare relapse rates between treatment arms to determine the effect size of adding BAT to oral ketamine. METHODS AND ANALYSIS: This is a prospectively registered, two-centre, single-blind RCT. We aim to recruit 60 participants with TR-MDD aged between 18 and 65 years. Participants will be randomised to 8 weeks of oral ketamine and BAT, or 8 weeks of oral ketamine alone. Feasibility will be assessed by tracking attendance for ketamine and BAT, acceptability of treatment measures and retention to the study follow-up protocol. The primary efficacy outcome measure is the Montgomery-Asberg Depression Rating Scale (MADRS) measured weekly during treatment and fortnightly during 12 weeks of follow-up. Other outcome measures will assess the tolerability of ketamine and BAT, cognition and activity (using actigraphy). Participants will be categorised as non-responders, responders, remitters and relapsed during follow-up. MADRS scores will be analysed using a linear mixed model. For a definitive follow-up RCT study to be recommended, the recruitment expectations will be met and efficacy outcomes consistent with a >20% reduction in relapse rates favouring the BAT and ketamine arm will be achieved. ETHICS AND DISSEMINATION: Ethics approval was granted by the New Zealand Central Health and Disability Ethics Committee (reference: 2023 FULL18176). Study findings will be reported to participants, stakeholder groups, conferences and peer-reviewed publications. TRIAL REGISTRATION NUMBER: UTN: U1111-1294-9310, ACTRN12623000817640p.