Estimating heterogeneity of treatment effect in psychiatric clinical trials.

Currently, placebo-controlled clinical trials report mean change and effect sizes, which masks information about heterogeneity of treatment effects (HTE). Here, we present a method to estimate HTE and evaluate the null hypothesis (H0) that a drug has equal benefit for all participants (HTE=0). We developed measure termed 'estimated heterogeneity of treatment effect' or eHTE, which estimates variability in drug response by comparing distributions between study arms. This approach was tested across numerous large placebo-controlled clinical trials. In contrast with variance-based methods which have not identified heterogeneity in psychiatric trials, reproducible instances of treatment heterogeneity were found. For example, heterogeneous response was found in a trial of venlafaxine for depression (peHTE=0.034), and two trials of dasotraline for binge eating disorder (Phase 2, peHTE=0.002; Phase 3, 4mg peHTE=0.011; Phase 3, 6mg peHTE=0.003). Significant response heterogeneity was detected in other datasets as well, often despite no difference in variance between placebo and drug arms. The implications of eHTE as a clinical trial outcomes independent from central tendency of the group is considered and the important of the eHTE method and results for drug developers, providers, and patients is discussed.

A multicenter, double-blind, placebo-controlled, randomized, Phase 1b crossover trial comparing two doses of ulotaront with placebo in the treatment of narcolepsy-cataplexy.

BACKGROUND: Ulotaront (SEP-363856) is a novel agonist at trace amine-associated receptor 1 and serotonin 5-HT1A receptors in clinical development for the treatment of schizophrenia. Previous studies demonstrated ulotaront suppresses rapid eye movement (REM) sleep in both rodents and healthy volunteers. We assessed acute and sustained treatments of ulotaront on REM sleep and symptoms of cataplexy and alertness in subjects with narcolepsy-cataplexy. METHODS: In a multicenter, double-blind, placebo-controlled, randomized, 3-way crossover study, ulotaront was evaluated in 16 adults with narcolepsy-cataplexy. Two oral doses of ulotaront (25 mg and 50 mg) were administered daily for 2 weeks and compared with matching placebo (6-treatment sequence, 3-period, 3-treatment). RESULTS: Acute treatment with both 25 mg and 50 mg of ulotaront reduced minutes spent in nighttime REM compared to placebo. A sustained 2-week administration of both doses of ulotaront reduced the mean number of short-onset REM periods (SOREMPs) during daytime multiple sleep latency test (MSLT) compared to placebo. Although cataplexy events decreased from the overall mean baseline during the 2-week treatment period, neither dose of ulotaront statistically separated from placebo (p = 0.76, 25 mg; p = 0.82, 50 mg), and no significant improvement in patient and clinician measures of sleepiness from baseline to end of the 2-week treatment period occurred in any treatment group. CONCLUSIONS: Acute and sustained treatment with ulotaront reduced nighttime REM duration and daytime SOREMPs, respectively. The effect of ulotaront on suppression of REM did not demonstrate a statistical or clinically meaningful effect in narcolepsy-cataplexy. REGISTRATION: ClinicalTrials.gov identifier: NCT05015673.

Current status and future directions for a neurotoxicity hazard assessment framework that integrates in silico approaches.

Neurotoxicology is the study of adverse effects on the structure or function of the developing or mature adult nervous system following exposure to chemical, biological, or physical agents. The development of more informative alternative methods to assess developmental (DNT) and adult (NT) neurotoxicity induced by xenobiotics is critically needed. The use of such alternative methods including in silico approaches that predict DNT or NT from chemical structure (e.g., statistical-based and expert rule-based systems) is ideally based on a comprehensive understanding of the relevant biological mechanisms. This paper discusses known mechanisms alongside the current state of the art in DNT/NT testing. In silico approaches available today that support the assessment of neurotoxicity based on knowledge of chemical structure are reviewed, and a conceptual framework for the integration of in silico methods with experimental information is presented. Establishing this framework is essential for the development of protocols, namely standardized approaches, to ensure that assessments of NT and DNT based on chemical structures are generated in a transparent, consistent, and defendable manner.

Ketamine for treatment of mood disorders and suicidality: A narrative review of recent progress.

BACKGROUND: Mood disorders are a leading cause of morbidity. Many patients experience treatment-resistant depression (TRD), and suicide rates are rising. Faster-acting and more effective antidepressant medications are needed. Four decades of research has transformed the use of ketamine from an anesthetic to an outpatient treatment for major depressive disorder (MDD). Ketamine is a N-methyl-d-aspartate (NMDA) receptor antagonist and has been shown to rapidly improve mood symptoms and suicidal ideation by targeting the glutamate system directly. METHODS: We used the PubMed database to identify relevant articles published until September 1, 2020. We focused on meta-analyses, randomized controlled trials, and original observational studies. We included relevant studies for depression, MDD, TRD, bipolar disorder, anxiety, posttraumatic stress disorder (PTSD), suicide, ketamine, and esketamine. RESULTS: Both racemic ketamine and esketamine have been shown to rapidly treat depression and suicidality. There is evidence that ketamine can be helpful for anxiety and PTSD; however, more research is needed. Intranasal esketamine has been FDA approved to treat depression. CONCLUSIONS: This narrative review describes the evolution of ketamine to treat mood disorders and suicidality. We provide the evidence supporting recent developments using esketamine as well as unresolved issues in the field, such as dosing and safety.

Enhancing cognitive restructuring with concurrent fMRI-guided neurostimulation for emotional dysregulation-A randomized controlled trial.

BACKGROUND: Transdiagnostic clinical emotional dysregulation is a key component of many mental health disorders and offers an avenue to address multiple disorders with one transdiagnostic treatment. In the current study, we pilot an intervention that combines a one-time teaching and practice of cognitive restructuring (CR) with repetitive transcranial magnetic stimulation (rTMS), targeted based on functional magnetic resonance imaging (fMRI). METHODS: Thirty-seven clinical adults who self-reported high emotional dysregulation were enrolled in this randomized, double-blind, placebo-controlled trial. fMRI was collected as participants were reminded of lifetime stressors and asked to downregulate their distress using CR tactics. fMRI BOLD data were analyzed to identify the cluster of voxels within the left dorsolateral prefrontal cortex (dlPFC) with the highest activation when participants attempted to downregulate, versus passively remember, distressing memories. Participants underwent active or sham rTMS (10 Hz) over the left dlPFC target while practicing CR following emotional induction using recent autobiographical stressors. RESULTS: Receiving active versus sham rTMS led to significantly higher high frequency heart rate variability during regulation, lower regulation duration during the intervention, and higher likelihood to use CR during the week following the intervention. There were no differences between conditions when administering neurostimulation alone without the CR skill and compared to sham. Participants in the sham versus active condition experienced less distress the week after the intervention. There were no differences between conditions at the one-month follow up. CONCLUSION: This study demonstrated that combining active rTMS with emotion regulation training for one session significantly enhances emotion regulation and augments the impact of training for as long as a week. These findings are a promising step towards a combined intervention for transdiagnostic emotion dysregulation.

Enhancing Cognitive Restructuring with Concurrent Repetitive Transcranial Magnetic Stimulation: A Transdiagnostic Randomized Controlled Trial.

INTRODUCTION: Emotional dysregulation constitutes a serious public health problem in need of novel transdiagnostic treatments. OBJECTIVE: To this aim, we developed and tested a one-time intervention that integrates behavioral skills training with concurrent repetitive transcranial magnetic stimulation (rTMS). METHODS: Forty-six adults who met criteria for at least one DSM-5 disorder and self-reported low use of cognitive restructuring (CR) were enrolled in a randomized, double-blind, sham-controlled trial that used a between-subjects design. Participants were taught CR and underwent active rTMS applied at 10 Hz over the right (n = 17) or left (n = 14) dorsolateral prefrontal cortex (dlPFC) or sham rTMS (n = 15) while practicing reframing and emotional distancing in response to autobiographical stressors. RESULTS: Those who received active left or active right as opposed to sham rTMS exhibited enhanced regulation (ds = 0.21-0.62) as measured by psychophysiological indices during the intervention (higher high-frequency heart rate variability, lower regulation duration). Those who received active rTMS over the left dlPFC also self-reported reduced distress throughout the intervention (d = 0.30), higher likelihood to use CR, and lower daily distress during the week following the intervention. The procedures were acceptable and feasible with few side effects. CONCLUSIONS: These findings show that engaging frontal circuits simultaneously with cognitive skills training and rTMS may be clinically feasible, well-tolerated and may show promise for the treatment of transdiagnostic emotional dysregulation. Larger follow-up studies are needed to confirm the efficacy of this novel therapeutic approach.

Mental Health and COVID-19: Challenges and Multimodal Clinical Solutions.

The Coronavirus Disease 2019 (COVID-19) pandemic has led to an exponential rise in mental health issues. Studies have shown that, in times of increased unemployment rates and economic downturn, rates of mental health issues, suicide, substance use, and domestic violence tend to increase. Barriers to care, including stigma and decreased access to providers, contribute to morbidity and mortality. Telehealth services are being utilized to help increase access to care, and economic stimulus packages have been created to help with the financial burden that is often associated with increased mental health stressors. Efforts to prevent burnout and other policy recommendations can help decrease mental health issues in first responders and health care professionals, who are at an increased risk for these problems. Increasing the ability to provide wellness screenings to the general population, to educate the public about preventive measures and practices, and to provide mental health and substance use treatment, such as medication management and therapy services, are among top priorities to further reduce the socioeconomic impact of COVID-19 on mental illness.

Switching to Intranasal Esketamine Maintains the Antidepressant Response to Intravenous Racemic Ketamine Administration: A Case Series of 10 Patients.

PURPOSE: This study aims to assess the efficacy and safety of intranasal (IN) esketamine as maintenance antidepressant therapy in patients who have demonstrated clinical improvement with off-label intravenous (IV) racemic ketamine for treatment-resistant depression (TRD). METHODS: This is a retrospective case series of 10 consecutive outpatients with TRD who all had a clinically meaningful response when treated with IV racemic ketamine and were then switched to IN esketamine for maintenance therapy. Patient outcomes were assessed with the Montgomery-Åsberg Depression Rating Scale, Patient Health Questionnaire 9, and Clinical Global Impression of Improvement scale at each visit. Adverse effects were assessed at each treatment. FINDINGS: Results indicated that 9 patients either maintained the benefit or showed greater improvement when transitioned to IN esketamine for antidepressant maintenance therapy. One patient had worsening of depression due to an acute psychosocial stressor but still improved from baseline IV racemic ketamine treatment. Six patients returned to work or pursued employment, and 4 patients with suicidal ideation remitted during IV racemic ketamine treatment and had no recurrence of suicidality with IN esketamine. No serious adverse reactions or tolerability issues were observed. IMPLICATIONS: This case series reports the outcomes of 10 severely ill patients with TRD who had a clinically meaningful response to IV racemic ketamine and demonstrated a maintenance of effect or continued improvement when transitioned to IN esketamine. Although this finding needs to be replicated in larger, controlled studies, this report provides promising results for patients who have safely and effectively switched to Food and Drug Administration-approved IN esketamine after receiving acute or maintenance depression treatment with off-label IV racemic ketamine.

Practical telehealth to improve control and engagement for patients with clinic-refractory diabetes mellitus (PRACTICE-DM): Protocol and baseline data for a randomized trial.

BACKGROUND: Persistent poorly-controlled type 2 diabetes mellitus (PPDM), or maintenance of a hemoglobin A1c (HbA1c) ≥8.5% despite receiving clinic-based diabetes care, contributes disproportionately to the national diabetes burden. Comprehensive telehealth interventions may help ameliorate PPDM, but existing approaches have rarely been designed with clinical implementation in mind, limiting use in routine practice. We describe a study testing a novel telehealth intervention that comprehensively targets clinic-refractory PPDM, and was explicitly developed for practical delivery using existing Veterans Health Administration (VHA) clinical infrastructure. METHODS: Practical Telehealth to Improve Control and Engagement for Patients with Clinic-Refractory Diabetes Mellitus (PRACTICE-DM) is an ongoing randomized controlled trial comparing two 12-month interventions: 1) standard VHA Home Telehealth (HT) telemonitoring/care coordination; or 2) the PRACTICE-DM intervention, a comprehensive HT-delivered intervention combining telemonitoring, self-management support, diet/activity support, medication management, and depression management. The primary outcome is HbA1c. Secondary outcomes include diabetes distress, self-care, self-efficacy, weight, depressive symptoms, implementation barriers/facilitators, and costs. We hypothesize that the PRACTICE-DM intervention will reduce HbA1c by >0.6% versus standard HT over 12 months. RESULTS: Enrollment for this ongoing trial concluded in January 2020; 200 patients were randomized (99 to standard HT and 101 to the PRACTICE-DM intervention). The cohort has a mean age of 58 and is 23% female and 72% African American. Mean baseline HbA1c and BMI were 10.2% and 34.8 kg/m2. CONCLUSIONS: Because it comprehensively targets factors underlying PPDM using existing clinical infrastructure, the PRACTICE-DM intervention may be well suited to lower the complications and costs of PPDM in routine practice.

A randomized proof-of-mechanism trial applying the 'fast-fail' approach to evaluating κ-opioid antagonism as a treatment for anhedonia.

The National Institute of Mental Health (NIMH) 'fast-fail' approach seeks to improve too-often-misleading early-phase drug development methods by incorporating biomarker-based proof-of-mechanism (POM) testing in phase 2a. This first comprehensive application of the fast-fail approach evaluated the potential of κ-opioid receptor (KOR) antagonism for treating anhedonia with a POM study determining whether robust target engagement favorably impacts the brain circuitry hypothesized to mediate clinical effects. Here we report the results from a multicenter, 8-week, double-blind, placebo-controlled, randomized trial in patients with anhedonia and a mood or anxiety disorder (selective KOR antagonist (JNJ-67953964, 10 mg; n = 45) and placebo (n = 44)). JNJ-67953964 significantly increased functional magnetic resonance imaging (fMRI) ventral striatum activation during reward anticipation (primary outcome) as compared to placebo (baseline-adjusted mean: JNJ-67953964, 0.72 (s.d. = 0.67); placebo, 0.33 (s.d. = 0.68); F(1,86) = 5.58, P < 0.01; effect size = 0.58 (95% confidence interval, 0.13-0.99)). JNJ-67953964, generally well tolerated, was not associated with any serious adverse events. This study supports proceeding with assessment of the clinical impact of target engagement and serves as a model for implementing the 'fast-fail' approach.

Effect of Pregnenolone vs Placebo on Self-reported Chronic Low Back Pain Among US Military Veterans: A Randomized Clinical Trial.

Importance: In response to the national opioid public health crisis, there is an urgent need to develop nonopioid solutions for effective pain management. Neurosteroids are endogenous molecules with pleotropic actions that show promise for safe and effective treatment of chronic low back pain. Objective: To determine whether adjunctive pregnenolone has therapeutic utility for the treatment of chronic low back pain in Iraq- and Afghanistan-era US military veterans. Design, Setting, and Participants: Randomized, double-blind, placebo-controlled clinical trial that enrolled for 42 months, from September 2013 to April 2017. Participants were Iraq- and Afghanistan-era veterans aged 18 to 65 years with chronic low back pain who received treatment in the Durham VA Health Care System in Durham, North Carolina, over 6 weeks. Data analysis began in 2018 and was finalized in March, 2019. Interventions: Following a 1-week placebo lead-in, participants were randomized to pregnenolone or placebo for 4 weeks. Pregnenolone and placebo were administered at fixed, escalating doses of 100 mg for 1 week, 300 mg for 1 week, and 500 mg for 2 weeks. Main Outcomes and Measures: The primary outcome measure was the change in mean pain intensity ratings from a daily pain diary (numerical rating scale, 0-10) between visit 3 (baseline) and visit 6. Secondary outcomes included pain interference scores (Brief Pain Inventory, Short Form). Preintervention and postintervention neurosteroid levels were quantified by gas chromatography with tandem mass spectrometry. Hypotheses tested were formulated prior to data collection. Results: A total of 94 participants (84 [89.4%] male; mean [SD] age, 37.5 [9.8] years; 53 [56.4%] of self-reported Caucasian race and 31 [33.0%] of self-reported African American race) were included. Forty-eight participants were randomized to pregnenolone and 52 to placebo, of whom 45 and 49, respectively, were included in baseline demographic characteristics secondary to noncompliance with medications as per protocol. Veterans randomized to pregnenolone reported significant reductions in low back pain relative to those randomized to placebo. Baseline unadjusted mean (SE) pain diary ratings were 4.83 (0.23) and 5.24 (0.22) for the placebo- and pregnenolone-treated groups, respectively (baseline unadjusted mean [SE] ratings for pain recall were 4.78 [0.24] and 5.15 [0.23], respectively). Unadjusted mean (SE) ratings following treatment (visit 6) were 4.74 (0.26) in the placebo group and 4.19 (0.30) in the pregnenolone-treated group. Unadjusted mean (SE) ratings for pain recall following treatment were 4.86 (0.27) for placebo and 4.18 (0.29) for pregnenolone. Least-square mean (LSM) analysis showed that pain scores significantly improved in the pregnenolone-treated group compared with placebo (LSM [SE] change in pain diary rating, -0.56 [0.25]; P = .02; LSM [SE] change in pain recall, -0.70 [0.27]; P = .01). Pain interference scores for work (LSM [SE] change, 0.71 [0.12]; P = .04) and activity (LSM [SE] change, 0.71 [0.11]; P = .03) were also improved in veterans randomized to pregnenolone compared with placebo. Pregnenolone was well tolerated. Conclusions and Relevance: Participants receiving pregnenolone reported a clinically meaningful reduction in low back pain and 2 pain interference domains compared with those receiving placebo. Pregnenolone may represent a novel, safe, and potentially efficacious treatment for the alleviation of chronic low back pain in Iraq- and Afghanistan-era veterans. Trial Registration: ClinicalTrials.gov Identifier: NCT01898013.

Beyond the looking glass: recent advances in understanding the impact of environmental exposures on neuropsychiatric disease.

The etiologic pathways leading to neuropsychiatric diseases remain poorly defined. As genomic technologies have advanced over the past several decades, considerable progress has been made linking neuropsychiatric disorders to genetic underpinnings. Interest and consideration of nongenetic risk factors (e.g., lead exposure and schizophrenia) have, in contrast, lagged behind heritable frameworks of explanation. Thus, the association of neuropsychiatric illness to environmental chemical exposure, and their potential interactions with genetic susceptibility, are largely unexplored. In this review, we describe emerging approaches for considering the impact of chemical risk factors acting alone and in concert with genetic risk, and point to the potential role of epigenetics in mediating exposure effects on transcription of genes implicated in mental disorders. We highlight recent examples of research in nongenetic risk factors in psychiatric disorders that point to potential shared biological mechanisms-synaptic dysfunction, immune alterations, and gut-brain interactions. We outline new tools and resources that can be harnessed for the study of environmental factors in psychiatric disorders. These tools, combined with emerging experimental evidence, suggest that there is a need to broadly incorporate environmental exposures in psychiatric research, with the ultimate goal of identifying modifiable risk factors and informing new treatment strategies for neuropsychiatric disease.

Efficacy and safety of ketamine in the management of anxiety and anxiety spectrum disorders: a review of the literature.

Anxiety disorders are among the most prevalent psychiatric conditions. Despite many proven pharmacological and non-pharmacological treatments available, high rates of partial response and low rates of long-term remission remain. Ketamine has been receiving increasing attention as an interventional treatment modality in psychiatry, especially among refractory conditions, including major depressive disorder. There is limited yet growing evidence to support the use of ketamine in anxiety disorders. In this review of the literature, we present case reports, case series, and controlled trials demonstrating proof-of-concept for its potential role in the treatment of anxiety and anxiety spectrum disorders. Its unique mechanism of action, rapid onset, and high rate of response have driven its use in clinical practice. Ketamine is generally well tolerated by patients and has a limited side effect profile; however, the effects of long-term use are unknown. While there is a growing body of research and increasing clinical experience to suggest ketamine may have clinical applications in the treatment of refractory anxiety disorders, further research to determine long-term safety and tolerability is indicated.

Widespread Cortical Thickness Is Associated With Neuroactive Steroid Levels.

BACKGROUND: Neuroactive steroids are endogenous molecules with regenerative and neuroprotective actions. Both cortical thickness and many neuroactive steroid levels decline with age and are decreased in several neuropsychiatric disorders. However, a systematic examination of the relationship between serum neuroactive steroid levels and in vivo measures of cortical thickness in humans is lacking. METHODS: Peripheral serum levels of seven neuroactive steroids were assayed in United States military veterans. All (n = 143) subsequently underwent high-resolution structural MRI, followed by parcellelation of the cortical surface into 148 anatomically defined regions. Regression modeling was applied to test the association between neuroactive steroid levels and hemispheric total gray matter volume as well as region-specific cortical thickness. False discovery rate (FDR) correction was used to control for Type 1 error from multiple testing. RESULTS: Neuroactive steroid levels of allopregnanolone and pregnenolone were positively correlated with gray matter thickness in multiple regions of cingulate, parietal, and occipital association cortices (r = 0.20-0.47; p < 0.05; FDR-corrected). CONCLUSION: Positive associations between serum neuroactive steroid levels and gray matter cortical thickness are found in multiple brain regions. If these results are confirmed, neuroactive steroid levels and cortical thickness may help in monitoring the clinical response in future intervention studies of neuroregenerative therapies.

Updates on Preclinical and Translational Neuroscience of Mood Disorders: A Brief Historical Focus on Ketamine for the Clinician.

BACKGROUND: The development of new-generation antidepressants comes at a time of great clinical need when the global burden of depression, suicide, and other psychiatric conditions continues to increase. Our current treatment armamentarium is limited by the time delay needed for antidepressant effects and the significant number of patients who do not show an adequate response to antidepressants. The past 2 decades of psychiatric research has revealed that ketamine, known to be used only as an anesthetic and drug of abuse and to produce experimental models of psychosis, is effective at subanesthetic doses to ameliorate clinical depression. METHODS: We performed a systematic search of PubMed/MEDLINE indexed reports to identify clinical and translational research done with ketamine for purposes of treating depression. RESULTS: We will first present the rationale for investigating ketamine and other N-methyl-D-aspartate receptor antagonists as a novel class of glutamate system targeting antidepressants. We will summarize putative molecular pathways underlying mood disorders and outline a brief history of investigation into ketamine as a treatment for depression. Recent clinical/translational evidence of ketamine's rapid-acting antidepressant mechanism will be critically reviewed in detail. CONCLUSIONS: At the end of this review, we will opine on the role of ketamine and derivatives in clinical practice.

Reducing Suicidal Ideation Through Insomnia Treatment (REST-IT): A Randomized Clinical Trial.

OBJECTIVE: The authors sought to determine whether targeted treatment of insomnia with controlled-release zolpidem (zolpidem-CR) in suicidal adults with insomnia would provide a reduction in suicidal ideation superior to placebo. METHODS: Reducing Suicidal Ideation Through Insomnia Treatment was an 8-week three-site double-blind placebo-controlled parallel-group randomized controlled trial of zolpidem-CR hypnotic therapy compared with placebo, in conjunction with an open-label selective serotonin reuptake inhibitor. Participants were medication-free 18- to 65-year-olds with major depressive disorder, insomnia, and suicidal ideation. Suicidal ideation was the main outcome, measured first by the Scale for Suicide Ideation and second by the Columbia-Suicide Severity Rating Scale (C-SSRS). RESULTS: A total of 103 participants were randomly assigned to receive zolpidem-CR (N=51) or placebo (N=52) (64 women and 39 men; mean age=40.5 years). Zolpidem-CR had a robust anti-insomnia effect, especially in patients with the most severe insomnia symptoms. No significant treatment effect was observed on the Scale for Suicide Ideation (least squares mean estimate=-0.56, SE=0.83, 95% CI=-2.19, 1.08), but the reduction in scores was significantly positively related to improvement in insomnia after accounting for the effect of other depression symptoms. The C-SSRS indicated that zolpidem-CR had a significant treatment effect (least squares mean estimate=-0.26, SE=0.12, 95% CI=-0.50, -0.02). The advantage for zolpidem-CR in reducing suicidal ideation on the C-SSRS was greater in patients with more severe insomnia. No deaths or suicide attempts occurred. CONCLUSIONS: Although the results do not support the routine prescription of hypnotic medication for mitigating suicidal ideation in all depressed outpatients with insomnia, they suggest that coprescription of a hypnotic during initiation of an antidepressant may be beneficial in suicidal outpatients, especially in patients with severe insomnia.

Resilience as a translational endpoint in the treatment of PTSD.

Resilience is a neurobiological entity that shapes an individual's response to trauma. Resilience has been implicated as the principal mediator in the development of mental illness following exposure to trauma. Although animal models have traditionally defined resilience as molecular and behavioral changes in stress responsive circuits following trauma, this concept needs to be further clarified for both research and clinical use. Here, we analyze the construct of resilience from a translational perspective and review optimal measurement methods and models. We also seek to distinguish between resilience, stress vulnerability, and posttraumatic growth. We propose that resilience can be quantified as a multifactorial determinant of physiological parameters, epigenetic modulators, and neurobiological candidate markers. This multifactorial definition can determine PTSD risk before and after trauma exposure. From this perspective, we propose the use of an 'R Factor' analogous to Spearman's g factor for intelligence to denote these multifactorial determinants. In addition, we also propose a novel concept called 'resilience reserve', analogous to Stern's cognitive reserve, to summarize the sum total of physiological processes that protect and compensate for the effect of trauma. We propose the development and application of challenge tasks to measure 'resilience reserve' and guide the assessment and monitoring of 'R Factor' as a biomarker for PTSD.

Neurobiological and immunogenetic aspects of narcolepsy: Implications for pharmacotherapy.

Excessive daytime sleepiness (EDS) and cataplexy are common symptoms of narcolepsy, a sleep disorder associated with the loss of hypocretin/orexin (Hcrt) neurons. Although only a few drugs have received regulatory approval for narcolepsy to date, treatment involves diverse medications that affect multiple biochemical targets and neural circuits. Clinical trials have demonstrated efficacy for the following classes of drugs as narcolepsy treatments: alerting medications (amphetamine, methylphenidate, modafinil/armodafinil, solriamfetol [JZP-110]), antidepressants (tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors), sodium oxybate, and the H3-receptor inverse agonist/antagonist pitolisant. Enhanced catecholamine availability and regulation of locus coeruleus (LC) norepinephrine (NE) neuron activity is likely central to the therapeutic activity of most of these compounds. LC NE neurons are integral to sleep/wake regulation and muscle tone; reduced excitatory input to the LC due to compromise of Hcrt/orexin neurons (likely due to autoimmune factors) results in LC NE dysregulation and contributes to narcolepsy/cataplexy symptoms. Agents that increase catecholamines and/or LC activity may mitigate EDS and cataplexy by elevating NE regulation of GABAergic inputs from the amygdala. Consequently, novel medications and treatment strategies aimed at preserving and/or modulating Hcrt/orexin-LC circuit integrity are warranted in narcolepsy/cataplexy.