Faculty Bibliography

Objective: Ketamine is a novel and rapidly acting treatment for major depressive disorder (MDD). Benzodiazepines are commonly coprescribed with antidepressants in MDD. This study sought to examine data from a randomized clinical trial that compared a single infusion of intravenous (IV) ketamine to midazolam placebo in treatment-resistant depression (DSM-IV-TR MDD) and to assess whether the use of concomitant oral benzodiazepines differentially affected treatment response to ketamine versus midazolam. Methods: This trial ran from December 2015 to December 2016. Subjects who were taking oral benzodiazepines (n = 44) were compared to those who were not (n = 55). A significant treatment-by-benzodiazepine effect could be interpreted as a possible moderator of differential treatment response to ketamine versus midazolam. Benzodiazepine use was examined as both a binary and a continuous predictor, to assess the impact of dosage. Results: Benzodiazepine users did not differ from non-users on the original study's primary outcome measure, score on the 6-item Hamilton Depression Rating Scale (HDRS-6), at baseline, but the former had more severe anxiety. When oral benzodiazepine use was modeled as a binary predictor, benzodiazepine use did not impact differential treatment response. However, when benzodiazepine dosage was considered, there was a significant impact of benzodiazepine use on differential treatment response. Oral benzodiazepines significantly impacted HDRS-6 (P = .018) and Clinical Global Impressions-Severity of Illness scale (CGI-S; P = .008) scores at day 1 (24 hours post treatment); effects were nonsignificant for all day 3 outcomes. Among ketamine subjects, higher doses of benzodiazepines were associated with less improvement in depression scores at day 1. Conclusions: Concomitant oral benzodiazepines at higher doses may attenuate the antidepressant effects of IV ketamine at day 1 but not day 3 post-infusion.

BACKGROUND:The heterogenous nature of depression continues to stymie efforts to identify biomarkers or predict treatment response. Efforts leveraging large datasets to define more uniform subtypes of depression or subgroups of depressed patients have considered only small subsets of symptoms. We aimed to understand how inclusion of more diverse complaints would impact data-emergent symptom and patient clusters. METHODS:We applied principal components analysis to baseline IDS data from 1491 STAR-D patients with major depressive disorder to derive naturally co-occurring symptom subsets before utilizing k-means clustering to divide patients into groups based on standardized residuals of each symptom subset score. We evaluated the clinical utility of our approach by comparing how cluster membership impacted response to citalopram. RESULTS:PCA identified nine naturally co-occurring symptom clusters: core affective symptoms, appetite/weight loss, anxiety, somatic symptoms, insomnia, negative intrusive thoughts, leaden paralysis/mood quality, diurnal mood variation, and irritability. Cluster analysis identified two patient groups, differing significantly in 7 of 9 clusters. Patients distinguished by the prominence of somatic vs. core affective symptoms exhibited greater reduction in depression severity with citalopram treatment. LIMITATIONS/CONCLUSIONS:Results depend not only on raw data, but also parameter selection, and interpretation. Replication is indicated. CONCLUSIONS:Findings are consistent with previous reports linking somatic symptoms and treatment resistance and demonstrating that SSRIs are most effective in treating affective symptoms. A novel distinction between physical somatic symptoms and psychic anxiety highlights the utility of assessing a broad spectrum of symptoms when exploring heterogeneity in depression and the need for treatments targeting physical somatic symptoms specifically.

BACKGROUND/UNASSIGNED:Previous studies have demonstrated elevated levels of the S100B protein (located in glial cells) in major depressive disorder (MDD) as compared to healthy controls. However, studies reporting correlation between S100B levels and depression severity have been conflicting. METHODS/UNASSIGNED:We investigated, through systematic review and meta-analysis, whether the correlation between S100B levels and depression severity is significant in patients with MDD. Pearson correlation coefficients reported in the individual studies were converted to Fisher's Z scores, then pooled using the random effects model. Meta-regression was used to test modifiers of the effect size. RESULTS/UNASSIGNED:16 studies including 658 patients with MDD met eligibility criteria. No publication bias was observed. There was a significant and positive correlation between serum S100B level and depression severity (r = 0.204, z = 2.297, p = 0.022). A meta-regression determined that onset age of MDD and percentage of female participants are significant modifiers of this correlation. A moderate, but non-significant heterogeneity was observed in serum studies (44%). CONCLUSION/UNASSIGNED:As many studies have reported significantly increased levels of S100B in MDD compared to controls, this meta-analysis supports the assumption that the increase in S100B correlates with the severity of MDD. Additional studies investigating the precise biological connection between S100B and MDD are indicated.

BACKGROUND:False suffocation alarm hypothesis has been widely used to explain carbon dioxide hypersensitivity in panic disorder (PD). However, hypersensitivity to carbon dioxide has been observed in other psychiatric disorders. We explored the specificity of carbon dioxide inhalation as a panic provocation test among psychiatric disorders via network meta-analysis. METHODS:A systematic literature search on PubMed, EMBASE, and PsycNET was performed to acquire the studies using the carbon dioxide provocation test in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and checklists. Odds ratios (OR) for a panic attack (PA) induced by the carbon dioxide inhalation tests were extracted from each of the original studies and were pooled using the random-effects model. RESULTS:Network meta-analysis on a pool of 2181 participants from 41 studies was used to compare the efficacy of carbon dioxide provocation tests among psychiatric disorders. The network meta-analysis showed that the odds for PA in response to carbon dioxide inhalation are higher in patients with PD, premenstrual dysphoric syndrome (PMDD), and social anxiety disorder (SAD) than healthy controls (HC). The odds for PA were not significantly different among patients with generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), major depressive disorder (MDD), and healthy controls (HC). CONCLUSIONS:The vulnerability to the carbon dioxide provocation test is not limited to PD. The specificity of the test for PD is questionable, as individuals suffering from PMDD and SAD are also significantly more responsive to carbon dioxide inhalation compared to HC, OCD, MDD, and GAD. There may be shared underpinning biological mechanisms between PD, PMDD, and SAD.

BACKGROUND:We aimed to study the probability of bipolar depression response at 24 weeks given initial non-response. METHODS:We combined two multi-site, 24-week trials including similar populations following the same evidence-based guidelines randomizing patients to lithium or quetiapine. Additional mood-stabilizing treatment was possible if clinically indicated. We report cumulative proportions of response (>50% improvement in MADRS) and remission (MADRS<10). RESULTS:We included 592 participants with bipolar depression (mean 39 years, 59% female, mean MADRS 25). Among 393 (66%) participants without response after 2 weeks, 46% responded by 24 weeks; for 291 (49%) without response at 4 weeks, 40% responded and 33% remitted by 24 weeks; for 222 (38%) without a response at 6 weeks, 36% responded and 29% remitted by 24 weeks; for 185 (31%) without a response at 8 weeks, 29% responded and 24% remitted by 24 weeks. Rates were similar for participants who had started an additional mood-stabilizing drug during the first 6 or 8 weeks. CONCLUSIONS:Among patients with bipolar depression and non-response after 6 weeks treatment, representing an adequate bipolar depression trial, only one-third responded by 24 weeks. These results highlight the need for better treatment alternatives for non-responders to evidence-based treatments for bipolar depression.

Reports an error in "Selective kappa-opioid antagonism ameliorates anhedonic behavior: Evidence from the fast-fail Trial in Mood and Anxiety Spectrum Disorders (FAST-MAS)" by Diego A. Pizzagalli, Moria Smoski, Yuen-Siang Ang, Alexis E. Whitton, Gerard Sanacora, Sanjay J. Mathew, John Nurnberger Jr., Sarah H. Lisanby, Dan V. Iosifescu, James W. Murrough, Hongqiu Yang, Richard D. Weiner, Joseph R. Calabrese, Wayne Goodman, William Z. Potter and Andrew D. Krystal (Neuropsychopharmacology, 2020[Sep], Vol 45[10], 1656-1663). In the original article, conflict of interest was missing. The co-author Sanjay J. Mathew served as a consultant to Alkermes. The original article has been corrected. (The following abstract of the original article appeared in record 2020-45589-001). Anhedonia remains a major clinical issue for which there is few effective interventions. Untreated or poorly controlled anhedonia has been linked to worse disease course and increased suicidal behavior across disorders. Taking a proof-of-mechanism approach under the auspices of the National Institute of Mental Health FAST-FAIL initiative, we were the first to show that, in a transdiagnostic sample screened for elevated self-reported anhedonia, 8 weeks of treatment with a kappa-opioid receptor (KOR) antagonist resulted in significantly higher reward-related activation in one of the core hubs of the brain reward system (the ventral striatum), better reward learning in the Probabilistic Reward Task (PRT), and lower anhedonic symptoms, relative to 8 weeks of placebo. Here, we performed secondary analyses of the PRT data to investigate the putative effects of KOR antagonism on anhedonic behavior with more precision by using trial-level model-based Bayesian computational modeling and probability analyses. We found that, relative to placebo, KOR antagonism resulted in significantly higher learning rate (i.e., ability to learn from reward feedback) and a more sustained preference toward the more frequently rewarded stimulus, but unaltered reward sensitivity (i.e., the hedonic response to reward feedback). Collectively, these findings provide novel evidence that in a transdiagnostic sample characterized by elevated anhedonia, KOR antagonism improved the ability to modulate behavior as a function of prior rewards. Together with confirmation of target engagement in the primary report (Krystal et al., Nat Med, 2020), the current findings suggest that further transdiagnostic investigation of KOR antagonism for anhedonia is warranted. (PsycInfo Database Record (c) 2021 APA, all rights reserved)

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method increasingly used to treat psychiatric disorders, primarily depression. Initial studies suggest that rTMS may help to treat addictions, but evaluation in multicenter randomized controlled trials (RCTs) is needed. We conducted a multicenter double-blind RCT in 262 chronic smokers meeting DSM-5 criteria for tobacco use disorder, who had made at least one prior failed attempt to quit, with 68% having made at least three failed attempts. They received three weeks of daily bilat-eral active or sham rTMS to the lateral prefrontal and insular cortices, followed by once weekly rTMS for three weeks. Each rTMS session was administered following a cue-induced craving procedure, and participants were monitored for a total of six weeks. Those in abstinence were monitored for additional 12 weeks. The primary outcome measure was the four-week continuous quit rate (CQR) until Week 18 in the intent-to-treat efficacy set, as determined by daily smoking diaries and verified by urine cotinine measures. The trial was registered at ClinicalTrials.gov (NCT02126124). In the intent-to-treat analysis set (N=234), the CQR until Week 18 was 19.4% following active and 8.7% following sham rTMS (X² =5.655, p=0.017). Among completers (N=169), the CQR until Week 18 was 28.0% and 11.7%, respectively (X² =7.219, p=0.007). The reduction in cigarette consumption and craving was significantly greater in the active than the sham group as early as two weeks into treatment. This study establishes a safe treatment protocol that promotes smoking cessation by stimulating relevant brain circuits. It represents the first large multicenter RCT of brain stimulation in addiction medicine, and has led to the first clearance by the US Food and Drug Administration for rTMS as an aid in smok-ing cessation for adults.

Major depressive disorder (MDD) is characterized by behavioral and neural abnormalities in processing both rewarding and aversive stimuli, which may impact motivational and affective symptoms. Learning paradigms have been used to assess reinforcement encoding abnormalities in MDD and their association with dysfunctional incentive-based behavior, but how the valence and context of information modulate this learning is not well understood. To address these gaps, we examined responses to positive and negative reinforcement across multiple temporal phases of information processing. While undergoing functional magnetic resonance imaging (fMRI), 47 participants (23 unmedicated, predominantly medication-naïve participants with MDD and 24 demographically-matched HC participants) completed a probabilistic, feedback-based reinforcement learning task that allowed us to separate neural activation during motor response (choice) from reinforcement feedback and monetary outcome across two independent conditions: pursuing gains and avoiding losses. In the gain condition, MDD participants showed overall blunted learning responses (prediction error) in the dorsal striatum when receiving monetary outcome, and reduced responses in ventral striatum for positive, but not negative, prediction error. The MDD group showed enhanced sensitivity to negative information, and symptom severity was associated with better behavioral performance in the loss condition. These findings suggest that striatal responses during learning are abnormal in individuals with MDD but vary with the valence of information.

BACKGROUND: Major depressive disorder (MDD) is a debilitating, chronic, biologically based condition. Current oral antidepressants act mainly via monoamine mechanisms and are associated with high rates of inadequate response and suboptimal time to response (Rush AJ et al. Am J Psychiatry 2006). There is an urgent need for faster-acting, more effective, and mechanistically novel treatments. AXS-05 (dextromethorphan-bupropion) is a novel, oral, investigational NMDA receptor antagonist with multimodal activity. AXS-05 utilizes a proprietary formulation and dose of dextromethorphan and bupropion, and metabolic inhibition technology, to modulate the delivery of the components. The dextromethorphan component of AXS-05 is an uncompetitive NMDA receptor antagonist and sigma-1 receptor agonist, and the bupropion component serves to increase the bioavailability of dextromethorphan.
OBJECTIVE(S): To evaluate the efficacy and safety of AXS-05 versus placebo in MDD.
METHOD(S): GEMINI was a phase 3, randomized, double-blind, placebo-controlled, multicenter, U.S. trial that enrolled subjects with a confirmed diagnosis of moderate-severe MDD. Subjects (N=327) were randomized (1:1) to receive AXS-05 (dextromethorphan 45 mg-bupropion 105 mg) or placebo, twice daily for 6 weeks. The primary efficacy endpoint was the change in the MADRS total score from baseline to week 6.
RESULT(S): On the primary endpoint, AXS-05 demonstrated a statistically significant mean reduction from baseline in the MADRS total score of 16.6 points versus 11.9 for placebo (P = .002). AXS-05 demonstrated rapid, statistically significant improvement versus placebo on the key secondary endpoint of change from baseline in the MADRS total score at week 1, the earliest time point measured (P = .007), and all time points thereafter. Rates of response were statistically significantly greater for AXS-05 versus placebo at week 1 (P = .035) and at all time points thereafter, being achieved by 54% of AXS-05 patients versus 34% of placebo patients at week 6 (P < .001). Remission rates were statistically significantly greater for AXS-05 versus placebo at week 2 (P = .013) and at all time points thereafter, being achieved by 40% of AXS-05 patients versus 17% of placebo patients at week 6 (P < .001). Antidepressant effects translated into early and statistically significant improvements in daily functioning and quality of life. AXS-05 was safe and well tolerated, with the most common adverse events being dizziness, nausea, and headache. AXS-05 was not associated with psychotomimetic effects, weight gain, or increased sexual dysfunction.
CONCLUSION(S): Treatment with AXS-05 resulted in rapid, substantial, durable, and statistically significant improvements in depressive symptoms across multiple efficacy endpoints versus placebo in patients with MDD. Symptomatic benefits translated into statistically significant improvements in daily functioning and quality of life. AXS-05 was safe and well tolerated