Faculty Bibliography

Lasting effects of adversity, such as exposure to childhood adversity (CA) on disease risk, may be embedded via epigenetic mechanisms but findings from human studies investigating the main effects of such exposure on epigenetic measures, including DNA methylation (DNAm), are inconsistent. Studies in perinatal tissues indicate that variability of DNAm at birth is best explained by the joint effects of genotype and prenatal environment. Here, we extend these analyses to postnatal stressors. We investigated the contribution of CA, cis genotype (G), and their additive (G + CA) and interactive (G × CA) effects to DNAm variability in blood or saliva from five independent cohorts with a total sample size of 1074 ranging in age from childhood to late adulthood. Of these, 541 were exposed to CA, which was assessed retrospectively using self-reports or verified through social services and registries. For the majority of sites (over 50%) in the adult cohorts, variability in DNAm was best explained by G + CA or G × CA but almost never by CA alone. Across ages and tissues, 1672 DNAm sites showed consistency of the best model in all five cohorts, with G × CA interactions explaining most variance. The consistent G × CA sites mapped to genes enriched in brain-specific transcripts and Gene Ontology terms related to development and synaptic function. Interaction of CA with genotypes showed the strongest contribution to DNAm variability, with stable effects across cohorts in functionally relevant genes. This underscores the importance of including genotype in studies investigating the impact of environmental factors on epigenetic marks.

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:Bipolar disorder is a heritable disorder, and we aimed to assess the impact of family history of mental disorders in first-degree relatives on the severity and course of bipolar disorder. METHODS:The Bipolar CHOICE (lithium versus quetiapine) and LiTMUS (optimized treatment with versus without lithium) comparative effectiveness studies were similar trials among bipolar disorder outpatients studying four different randomized treatment arms for 24 weeks. Patients self-reported on six severe mental disorders among first-degree relatives. We performed ANOVA and linear regression regarding disease severity measures, sociodemographic and cardiometabolic markers and mixed effects linear regression to evaluate treatment response. RESULTS:Among 757 patients, 644 (85.1%) reported at least one first-degree relative with a severe mental disorder (mean=2.8; standard deviation=2.2; range=0-13). Depression (67.1%), alcohol abuse (51.0%) and bipolar disorder (47.0%) were the most frequently reported disorders. Familial psychiatric history correlated with several disease severity measures (hospitalizations, suicide attempts, and earlier onset) and sociodemographic markers (lower education and household income) but not with cardiometabolic markers (e.g. cholesterol or waist circumference) or cardiovascular risk scores, e.g. the Framingham risk score. Patients with familial psychiatric history tended to require more psychopharmacological treatment (p=0.054) but responded similarly (all p>0.1) to all four treatment arms. CONCLUSIONS:Our findings indicate that familial psychiatric history is common among outpatients with bipolar disorder and correlates with disease severity and sociodemographic measures. Patients with a greater familial psychiatric load required more intense treatment but achieved similar treatment responses compared to patients without familial psychiatric history.

We report on the rationale and design of an ongoing NIMH sponsored R61-R33 project in schizophrenia/schizoaffective disorder. This project studies augmenting the efficacy of auditory neuroplasticity cognitive remediation (AudRem) with d-serine, an N-methyl-d-aspartate-type glutamate receptor (NMDAR) glycine-site agonist. We operationalize improved (smaller) thresholds in pitch (frequency) between successive auditory stimuli after AudRem as improved plasticity, and mismatch negativity (MMN) and auditory θ as measures of functional target engagement of both NMDAR agonism and plasticity. Previous studies showed that AudRem alone produces significant, but small cognitive improvements, while d-serine alone improves symptoms and MMN. However, the strongest results for plasticity outcomes (improved pitch thresholds, auditory MMN and θ) were found when combining d-serine and AudRem. AudRem improvements correlated with reading and other auditory cognitive tasks, suggesting plasticity improvements are predictive of functionally relevant outcomes. While d-serine appears to be efficacious for acute AudRem enhancement, the optimal dose remains an open question, as does the ability of combined d-serine + AudRem to produce sustained improvement. In the ongoing R61, 45 schizophrenia patients will be randomized to receive three placebo-controlled, double-blind d-serine + AudRem sessions across three separate 15 subject dose cohorts (80/100/120 mg/kg). Successful completion of the R61 is defined by ≥moderate effect size changes in target engagement and correlation with function, without safety issues. During the three-year R33, we will assess the sustained effects of d-serine + AudRem. In addition to testing a potentially viable treatment, this project will develop a methodology to assess the efficacy of novel NMDAR modulators, using d-serine as a "gold-standard".

Anxiety disorders are the most prevalent psychiatric disorders and a leading cause of disability. While there continues to be expansive research in posttraumatic stress disorder (PTSD), depression and schizophrenia, there is a relative dearth of novel medications under investigation for anxiety disorders. This review's first aim is to summarize current pharmacological treatments (both approved and off-label) for panic disorder (PD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and specific phobias (SP), including selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), azapirones (e.g., buspirone), mixed antidepressants (e.g., mirtazapine), antipsychotics, antihistamines (e.g., hydroxyzine), alpha- and beta-adrenergic medications (e.g., propranolol, clonidine), and GABAergic medications (benzodiazepines, pregabalin, and gabapentin). Posttraumatic stress disorder and obsessive-compulsive disorder are excluded from this review. Second, we will review novel pharmacotherapeutic agents under investigation for the treatment of anxiety disorders in adults. The pathways and neurotransmitters reviewed include serotonergic agents, glutamate modulators, GABAergic medications, neuropeptides, neurosteroids, alpha- and beta-adrenergic agents, cannabinoids, and natural remedies. The outcome of the review reveals a lack of randomized double-blind placebo- controlled trials for anxiety disorders and few studies comparing novel treatments to existing anxiolytic agents. Although there are some recent randomized controlled trials for novel agents including neuropeptides, glutamatergic agents (such as ketamine and d-cycloserine), and cannabinoids (including cannabidiol) primarily in GAD or SAD, these trials have largely been negative, with only some promise for kava and PH94B (an inhaled neurosteroid). Overall, the progression of current and future psychopharmacology research in anxiety disorders suggests that there needs to be further expansion in research of these novel pathways and larger-scale studies of promising agents with positive results from smaller trials.

Background: Major depressive disorder (MDD) is a debilitating and prevalent condition. Nearly two-thirds of treated patients with MDD do not experience an adequate response to first-line therapy, and most of these inadequate responders also fail second-line treatment. Time to clinically meaningful response with currently available antidepressants (up to 6-8 weeks) is also suboptimal. There is an urgent need for new, more effective, mechanistically novel, and faster-acting MDD treatments. AXS-05 (dextromethorphan/bupropion modulated delivery tablet) is a novel, oral, investigational NMDA receptor antagonist with multimodal activity, including sigma-1 receptor agonism. AXS-05 is being developed for the treatment of MDD.
Objective(s): To evaluate the efficacy and safety of AXS-05 versus placebo in MDD.
Method(s): The GEMINI study is a Phase 3, randomized, double-blind, placebo-controlled, multi-center, which enrolled subjects with a confirmed diagnosis of moderate to severe MDD. Three hundred twenty-seven (327) subjects were randomised (1:1) to receive AXS-05 (45 mg DM/105 mg bupropion) or placebo, twice daily for 6 weeks. The primary efficacy endpoint was the change in the Montgomery-Asberg Depression Rating Scale (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=0.002) after 6 weeks of treatment. AXS-05 rapidly, substantially and durably reduced depressive symptoms, demonstrating a statistically significant improvement compared to placebo on the key secondary endpoint of change from baseline in the MADRS total score at Week 1, the earliest time point measured (p=0.007), and at all timepoints thereafter. Rates of response (>= 50% MADRS improvement) were statistically significantly greater for AXS-05 compared to placebo at Week 1 (p=0.035) and at every time point thereafter, being achieved by 54% of AXS-05 patients versus 34% of placebo patients at Week 6 (p<0.001). Rates of remission (MADRS <=10) were statistically significantly greater for AXS-05 compared to placebo at Week 2 (p=0.013) and at every time point thereafter, being achieved by 40% of AXS-05 patients versus 17% of placebo patients at Week 6 (p<0.001). The observed rapid and durable antidepressant effects translated into early and statistically significant improvements in daily functioning as measured by the Sheehan Disability Scale, and in quality of life as measured by the Quality of Life Enjoyment and Satisfaction Questionnaire. AXS-05 was safe and well tolerated with the most commonly reported adverse events being dizziness, nausea, headache, diarrhea, somnolence and dry mouth. Treatment with AXS-05 was not associated with psychotomimetic effects. Rates of discontinuation due to adverse events in the trial were low (6.2% for AXS-05 and 0.6% for placebo).
Conclusion(s): Treatment with AXS-05 resulted in rapid, substantial, durable and statistically significant improvements in depressive symptomatology across multiple efficacy endpoints as compared to placebo in patients with MDD. Symptomatic benefits translated into statistically significant improvements on validated measures of daily functioning and quality of life. AXS-05 was safe and well tolerated in this trial and was not associated with psychotomimetic effects. Disclosure statement: Employee and shareholder of Axsome Therapeutics Inc.
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Interoceptive sensibility (IS) refers to the subjective experience of perceiving and being aware of one's internal body sensations, and is typically evaluated using self-report questionnaires or confidence ratings. Here we evaluated IS in 81 patients with OCD and 76 controls using the Multidimensional Scale of Interoceptive Awareness (MAIA), which contains 8 subscales assessing adaptive and maladaptive responses to sensation. Compared to controls, OCD patients showed hyperawareness of body sensations. Patients also demonstrated a more maladaptive profile of IS characterized by greater distraction from and worry about unpleasant sensations, and reduced tendency to experience the body as safe and trustworthy. These findings were independent of medication status and comorbidities in the patient group. Correlational analyses showed that subscales of the MAIA were differentially associated with OCD symptom dimensions. These findings indicate that patients with OCD show abnormality of IS that is independent of confounding factors related to medication and comorbidities and associated with different OCD symptom dimensions. Future work would benefit from examining neural correlates of these effects and evaluating whether dimensions of IS are impacted by treatments for the disorder.