Clinical, behavioral, and electrophysiological profiles along a continuum of suicide risk: evidence from an implicit association task.

BACKGROUND: An urgent need exists to identify neural correlates associated with differing levels of suicide risk and develop novel, rapid-acting therapeutics to modulate activity within these neural networks. METHODS: Electrophysiological correlates of suicide were evaluated using magnetoencephalography (MEG) in 75 adults with differing levels of suicide risk. During MEG scanning, participants completed a modified Life-Death Implicit Association Task. MEG data were source-localized in the gamma (30-58 Hz) frequency, a proxy measure of excitation-inhibition balance. Dynamic causal modeling was used to evaluate differences in connectivity estimates between risk groups. A proof-of-concept, open-label, pilot study of five high risk participants examined changes in gamma power after administration of ketamine (0.5 mg/kg), an NMDAR antagonist with rapid anti-suicide ideation effects. RESULTS: Implicit self-associations with death were stronger in the highest suicide risk group relative to all other groups, which did not differ from each other. Higher gamma power for self-death compared to self-life associations was found in the orbitofrontal cortex for the highest risk group and the insula and posterior cingulate cortex for the lowest risk group. Connectivity estimates between these regions differentiated the highest risk group from the full sample. Implicit associations with death were not affected by ketamine, but enhanced gamma power was found for self-death associations in the left insula post-ketamine compared to baseline. CONCLUSIONS: Differential implicit cognitive processing of life and death appears to be linked to suicide risk, highlighting the need for objective measures of suicidal states. Pharmacotherapies that modulate gamma activity, particularly in the insula, may help mitigate risk.Clinicaltrials.gov identifier: NCT02543983, NCT00397111.

International pooled patient-level meta-analysis of ketamine infusion for depression: In search of clinical moderators.

Depression is disabling and highly prevalent. Intravenous (IV) ketamine displays rapid-onset antidepressant properties, but little is known regarding which patients are most likely to benefit, limiting personalized prescriptions. We identified randomized controlled trials of IV ketamine that recruited individuals with a relevant psychiatric diagnosis (e.g., unipolar or bipolar depression; post-traumatic stress disorder), included one or more control arms, did not provide any other study-administered treatment in conjunction with ketamine (although clinically prescribed concurrent treatments were allowable), and assessed outcome using either the Montgomery-Åsberg Depression Rating Scale or the Hamilton Rating Scale for Depression (HRSD-17). Individual patient-level data for at least one outcome was obtained from 17 of 25 eligible trials [pooled n = 809]. Rates of participant-level data availability across 33 moderators that were solicited from these 17 studies ranged from 10.8% to 100% (median = 55.6%). After data harmonization, moderators available in at least 40% of the dataset were tested sequentially, as well as with a data-driven, combined moderator approach. Robust main effects of ketamine on acute [~24-hours; ß*(95% CI) = 0.58 (0.44, 0.72); p < 0.0001] and post-acute [~7 days; ß*(95% CI) = 0.38 (0.23, 0.54); p < 0.0001] depression severity were observed. Two study-level moderators emerged as significant: ketamine effects (relative to placebo) were larger in studies that required a higher degree of previous treatment resistance to federal regulatory agency-approved antidepressant medications (≥2 failed trials) for study entry; and in studies that used a crossover design. A comprehensive data-driven search for combined moderators identified statistically significant, but modest and clinically uninformative, effects (effect size r ≤ 0.29, a small-medium effect). Ketamine robustly reduces depressive symptoms in a heterogeneous range of patients, with benefit relative to placebo even greater in patients more resistant to prior medications. In this largest effort to date to apply precision medicine approaches to ketamine treatment, no clinical or demographic patient-level features were detected that could be used to guide ketamine treatment decisions.Review Registration: PROSPERO Identifier: CRD42021235630.

Suicide Biomarkers to Predict Risk, Classify Diagnostic Subtypes, and Identify Novel Therapeutic Targets: 5 Years of Promising Research.

BACKGROUND: Suicide is a global health crisis. However, no objective biomarkers of suicide risk currently exist, and self-reported data can be unreliable, which limits prediction, diagnostic, and treatment efforts. Reliable biomarkers that can differentiate between diagnostic subgroups, predict worsening symptoms, or suggest novel therapeutic targets would be extremely valuable for patients, researchers, and clinicians. METHODS: MEDLINE was searched for reports published between 2016 and 2021 using search terms (suicid*) AND (biomarker*) OR (indicat*). Reports that compared biomarkers between suicidal ideation, suicide attempt, death from suicide, or any suicide subgroup against other neuropsychiatric disorders were included. Studies exclusively comparing suicidal behavior or death from suicide with healthy controls were not included to ensure that biomarkers were specific to suicide and not other psychopathology. RESULTS: This review summarizes the last 5 years of research into suicide-associated biomarkers and provides a comprehensive guide for promising and novel biomarkers that encompass varying presentations of suicidal ideation, suicide attempt, and death by suicide. The serotonergic system, inflammation, hypothalamic-pituitary-adrenal axis, lipids, and endocannabinoids emerged as the most promising diagnostic, predictive, and therapeutic indicators. CONCLUSIONS: The utility of diagnostic and predictive biomarkers is evident, particularly for suicide prevention. While larger-scale studies and further in-depth research are required, the last 5 years of research has uncovered essential biomarkers that could ultimately improve predictive strategies, aid diagnostics, and help develop future therapeutic targets.

A Participant-Level Integrative Data Analysis of Differential Placebo Response for Suicidal Ideation and Nonsuicidal Depressive Symptoms in Clinical Trials of Intravenous Racemic Ketamine.

BACKGROUND: Clinical trials of intravenous (IV) racemic (R,S)-ketamine (hereafter referred to as IV ketamine) have consistently reported rapid and substantial reductions in overall depressive symptoms compared with saline (inactive placebo) or midazolam (active placebo). The evidence for IV ketamine's specific effects on suicidal ideation is less clear, however. This study sought to examine whether differential placebo (saline or midazolam) response to overall depressive symptoms vs suicidal ideation may help explain these divergent findings. METHODS: Data for this participant-level integrative data analysis were drawn from 151 participants across 10 studies, and linear regression was used to examine the relationship between placebo response for suicidal ideation vs other depressive symptoms indexed from standard rating scales-specifically, depressed mood, anhedonia, anxiety, and guilt-over time. RESULTS: For participants receiving saline placebo (n = 46), greater placebo response was observed for suicidal ideation compared with other symptoms indexed from standard depression rating scales, except for anxiety. For those receiving midazolam placebo (n = 105), greater placebo response was observed for suicidal ideation compared with depressed mood or anhedonia, and no significant differences were observed when comparing suicidal ideation with anxiety or guilt. CONCLUSIONS: Taken together, the results provide preliminary evidence of a differential placebo response for suicidal ideation vs other depressive symptoms, while anxiety and suicidal ideation appear to produce similar placebo response profiles. These findings may help explain the more modest findings in clinical IV ketamine trials for suicidal ideation than overall depression.

The kynurenine pathway and bipolar disorder: intersection of the monoaminergic and glutamatergic systems and immune response.

Dysfunction in a wide array of systems-including the immune, monoaminergic, and glutamatergic systems-is implicated in the pathophysiology of depression. One potential intersection point for these three systems is the kynurenine (KYN) pathway. This study explored the impact of the prototypic glutamatergic modulator ketamine on the endogenous KYN pathway in individuals with bipolar depression (BD), as well as the relationship between response to ketamine and depression-related behavioral and peripheral inflammatory markers. Thirty-nine participants with treatment-resistant BD (23 F, ages 18-65) received a single ketamine infusion (0.5 mg/kg) over 40 min. KYN pathway analytes-including plasma concentrations of indoleamine 2,3-dioxygenase (IDO), KYN, kynurenic acid (KynA), and quinolinic acid (QA)-were assessed at baseline (pre-infusion), 230 min, day 1, and day 3 post-ketamine. General linear models with restricted maximum likelihood estimation and robust sandwich variance estimators were implemented. A repeated effect of time was used to model the covariance of the residuals with an unstructured matrix. After controlling for age, sex, and body mass index (BMI), post-ketamine IDO levels were significantly lower than baseline at all three time points. Conversely, ketamine treatment significantly increased KYN and KynA levels at days 1 and 3 versus baseline. No change in QA levels was observed post-ketamine. A lower post-ketamine ratio of QA/KYN was observed at day 1. In addition, baseline levels of proinflammatory cytokines and behavioral measures predicted KYN pathway changes post ketamine. The results suggest that, in addition to having rapid and sustained antidepressant effects in BD participants, ketamine also impacts key components of the KYN pathway.

Ketamine has distinct electrophysiological and behavioral effects in depressed and healthy subjects.

Ketamine's mechanism of action was assessed using gamma power from magnetoencephalography (MEG) as a proxy measure for homeostatic balance in 35 unmedicated subjects with major depressive disorder (MDD) and 25 healthy controls enrolled in a double-blind, placebo-controlled, randomized cross-over trial of 0.5 mg/kg ketamine. MDD subjects showed significant improvements in depressive symptoms, and healthy control subjects exhibited modest but significant increases in depressive symptoms for up to 1 day after ketamine administration. Both groups showed increased resting gamma power following ketamine. In MDD subjects, gamma power was not associated with the magnitude of the antidepressant effect. However, baseline gamma power was found to moderate the relationship between post-ketamine gamma power and antidepressant response; specifically, higher post-ketamine gamma power was associated with better response in MDD subjects with lower baseline gamma, with an inverted relationship in MDD subjects with higher baseline gamma. This relationship was observed in multiple regions involved in networks hypothesized to be involved in the pathophysiology of MDD. This finding suggests biological subtypes based on the direction of homeostatic dysregulation and has important implications for inferring ketamine's mechanism of action from studies of healthy controls alone.

Symptom trajectories in the months before and after a suicide attempt in individuals with bipolar disorder: A STEP-BD study.

OBJECTIVES: The suicide crisis is a relatively short-lived psychiatric emergency, with transient symptoms that ebb and flow around the suicide attempt. Understanding the dynamic processes of symptoms before and after suicide attempt may aid future prevention efforts. METHODS: Data were drawn from the NIMH STEP-BD study, which followed 4,360 patients with bipolar disorder; a subset attempted suicide during the trial (245/4100 or 5.97% of the sample eligible for analysis). This analysis focused on change in suicidal ideation (SI) in the 120 days before and 120 days after suicide attempt; similar analyses were conducted for other depressive symptoms. Generalized linear mixed models with a two-piece linear function of time corresponding to pre- and post-suicide attempt trends were used. RESULTS: SI ratings from 216 individuals were analyzed (n = 1,231 total; n = 395 pre-attempt, n = 126 circa-attempt, n = 710 post-attempt) and compared to data from a matched sample of 648 non-attempters. SI worsened in the 120 days pre-attempt but improved afterwards, reaching non-attempter levels by 90 days post-attempt. A similar pattern was found for other depressive symptoms, including depressed mood, loss of interest, guilt, and self-esteem. Pre/post differences in tension/activating symptoms of depression-anxiety, agitation, and irritability-were less pronounced and more time-limited. CONCLUSIONS: The suicide crisis is dynamic, and the days before and after suicide attempt may be particularly critical. The findings extend previous research on proximal symptoms of suicide and underscore that some SI and affective/cognitive symptoms of depression can remain elevated up to 90 days post-attempt in individuals with bipolar disorder.

Research on the pathophysiology, treatment, and prevention of suicide: practical and ethical issues.

BACKGROUND: Despite decades of research, the rate of death from suicide is rising in the United States. Suicide is a complex and multifactorial phenomenon and, to date, no validated biomarkers that predict suicidal behavior have been identified. Only one FDA-approved drug to prevent suicide exists, and it is approved only for patients with schizophrenia. Although anti-suicide psychotherapeutic techniques exist, treatment takes time, and only preliminary data exist for rapid-acting therapies. DISCUSSION: While more research into suicidal ideation and acute suicidal behavior is clearly needed, this research is fraught with both practical and ethical concerns. As a result, many investigators and bioethicists have called for restrictions on the types of research that individuals with suicidal behavior can participate in, despite the fact that the available empirical evidence suggests that this research can be done safely. This manuscript presents background information on the phenomenology of suicide, discusses the current state of treatment and prevention strategies, and reviews the practical and ethical issues surrounding suicide research in the context of available empirical data. Currently, the causes of suicide are poorly understood, in part due to the fact that very few studies have investigated the acute suicidal crisis. Although some biomarkers for predicting risk have been developed, none have been sufficiently validated. The most successful current interventions involve means restriction. However, while numerous hurdles face researchers, these are not insurmountable. The available evidence suggests that research into suicide can be conducted both safely and ethically.

Ketamine-Induced Glutamatergic Mechanisms of Sleep and Wakefulness: Insights for Developing Novel Treatments for Disturbed Sleep and Mood.

Ketamine, a drug with rapid antidepressant effects and well-described effects on slow wave sleep (SWS), is a useful intervention for investigating sleep-wake mechanisms involved in novel therapeutics. The drug rapidly (within minutes to hours) reduces depressive symptoms in individuals with major depressive disorder (MDD) or bipolar disorder (BD), including those with treatment-resistant depression. Ketamine treatment elevates extracellular glutamate in the prefrontal cortex. Glutamate, in turn, plays a critical role as a proximal element in a ketamine-initiated molecular cascade that increases synaptic strength and plasticity, which ultimately results in rapidly improved mood. In MDD, rapid antidepressant response to ketamine is related to decreased waking as well as increased total sleep, SWS, slow wave activity (SWA), and rapid eye movement (REM) sleep. Ketamine also increases brain-derived neurotrophic factor (BDNF) levels. In individuals with MDD, clinical response to ketamine is predicted by low baseline delta sleep ratio, a measure of deficient early night production of SWS. Notably, there are important differences between MDD and BD that may be related to the effects of diagnosis or of mood stabilizers. Consistent with its effects on clock-associated molecules, ketamine alters the timing and amplitude of circadian activity patterns in rapid responders versus non-responders with MDD, suggesting that it affects mood-dependent central neural circuits. Molecular interactions between sleep homeostasis and clock genes may mediate the rapid and durable elements of clinical response to ketamine and its active metabolite.

Clinical Trial of the Potassium Channel Activator Diazoxide for Major Depressive Disorder Halted Due to Intolerability.

BACKGROUND: Some glutamatergic modulators have demonstrated rapid and relatively sustained antidepressant properties in patients with major depressive disorder. Because the potassium channel activator diazoxide increases glutamate uptake via potassium channel activation, we hypothesized that it might exert antidepressant effects by increasing the removal of glutamate from the synaptic cleft, thereby reducing excessive glutamate transmission. METHODS: This randomized, double-blind, placebo-controlled, crossover, single-site inpatient clinical study was conducted at the National Institute of Mental Health to assess the efficacy and safety of a 3-week course of diazoxide (200-400 mg daily, twice a day) versus a 3-week course of placebo in 6 participants with treatment-refractory major depressive disorder. The primary clinical outcome measure was change in Montgomery-Asberg Depression Rating Scale score from baseline to posttreatment. Quantitative insulin sensitivity check index, as well as concomitant imaging measures (electroencephalography, proton magnetic resonance spectroscopy, magnetoencephalography), were used as potential surrogate markers of target (KATP channel) engagement. RESULTS: The study was halted due to severe adverse effects. Given the small sample size, statistical evaluation of the effect of diazoxide on Montgomery-Asberg Depression Rating Scale scores or the imaging measures was not pursued. Visual inspection of the quantitative insulin sensitivity check index test revealed no evidence of target engagement. CONCLUSIONS: Although the results are negative, they are an important addition to the literature in this rapidly changing field.

Identification of At-Risk Youth by Suicide Screening in a Pediatric Emergency Department.

The pediatric emergency department (ED) is a critical location for the identification of children and adolescents at risk for suicide. Screening instruments that can be easily incorporated into clinical practice in EDs to identify and intervene with patients at increased suicide risk is a promising suicide prevention strategy and patient safety objective. This study is a retrospective review of the implementation of a brief suicide screen for pediatric psychiatric ED patients as standard of care. The Ask Suicide Screening Questions (ASQ) was implemented in an urban pediatric ED for patients with psychiatric presenting complaints. Nursing compliance rates, identification of at-risk patients, and sensitivity for repeated ED visits were evaluated using medical records from 970 patients. The ASQ was implemented with a compliance rate of 79 %. Fifty-three percent of the patients who screened positive (237/448) did not present to the ED with suicide-related complaints. These identified patients were more likely to be male, African American, and have externalizing behavior diagnoses. The ASQ demonstrated a sensitivity of 93 % and specificity of 43 % to predict return ED visits with suicide-related presenting complaints within 6 months of the index visit. Brief suicide screening instruments can be incorporated into standard of care in pediatric ED settings. Such screens can identify patients who do not directly report suicide-related presenting complaints at triage and who may be at particular risk for future suicidal behavior. Results have the potential to inform suicide prevention strategies in pediatric EDs.

Acute risk factors for suicide attempts and death: prospective findings from the STEP-BD study.

OBJECTIVES: Suicide is unfortunately common in psychiatric practice, but difficult to predict. The present study sought to assess which clinical symptoms increase in the months before suicidal behavior in a sample of psychiatric outpatients with bipolar disorder. METHODS: Data from the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) trial were used. A total of 103 participants who attempted suicide or died by suicide during the trial were included; a 15% random sample of the remaining participants (n = 427) was used as a comparison sample. Linear mixed models in the six months before suicidal behavior were conducted for each of five proposed acute risk factors for suicidal behavior. Participants were assessed using the Clinical Monitoring Form (CMF) at each visit for the following potential acute risk factors for suicidal behavior: suicidal ideation, loss of interest, anxiety, psychomotor agitation, and high-risk behavior. RESULTS: Each of the five symptoms was elevated overall in individuals who engaged in suicidal behavior (p < 0.05). The severity of both suicidal ideation and loss of interest significantly increased in the months before suicidal behavior (p < 0.001). Anxiety demonstrated comparable effect sizes across multiple models. Psychomotor agitation and high-risk behavior were not significantly elevated before suicidal behavior. CONCLUSIONS: Suicidal ideation, loss of interest and, to a lesser extent, anxiety may represent acute suicide risk factors up to four months before suicidal behavior in outpatients with bipolar disorder. Further investigation of these potential acute risk factors in prospective analyses is warranted.

Quantifying the influence of child abuse history on the cardinal symptoms of fibromyalgia.

OBJECTIVES: To quantify the influence of abuse, particularly in childhood, with pain sensitivity and other adverse symptoms experienced by women with fibromyalgia (FM). METHODS: Subjects with FM completed a detailed abuse interview, dolorimetry, and questionnaire-based assessments of fatigue, cognitive self-appraisal, and depression. Student's t- and chi-square tests were used to analyse differences in FM symptoms between those with and without a history of childhood abuse. Linear regression was used to evaluate the relationship between abuse and symptom severity, adjusting for possible confounders. RESULTS: In 111 women with FM, physical abuse during childhood demonstrated a clinically modest, yet statistically significant, association with increased tenderness as measured by pain pressure thresholds (ß=-0.25, p=0.011) and tender points (ß=0.23, p=.022). Physical child abuse was also associated with cognitive language impairment after adjusting for depression (ß=0.27, p=0.001). While emotional child abuse was associated with fatigue, the association did not persist after adjustment for depressive symptoms. CONCLUSIONS: Group differences are of small magnitude and might not directly impact clinical practice, however, the experience of child abuse is associated with FM symptom severity and may shape the biological development of interoception in ways that predispose to pain and polysymptomatic distress.

Recognition of emotional facial expressions in anxious and nonanxious depression.

BACKGROUND: Anxiety and depression have each been independently associated with impairments in emotional face recognition. However, little is known about the nature of these impairments when anxiety and depression co-occur. METHODS: This post-hoc analysis evaluated the relationship between anxiety status and performance on the Emotional Expression Multimorph Task within a clinical sample of individuals with major depressive disorder (MDD). RESULTS: Participants with anxious depression (n=14) and nonanxious depression (n=14) completed the Emotional Expression Multimorph Task. Those with anxious depression required greater intensity of emotion to identify both happy (p=.01) and sad (p=.04) facial expressions than those with nonanxious depression. Severity of anxiety also correlated with greater intensity of emotion required to detect sad faces. Contrary to prediction, hypervigilance to angry and fearful facial expressions was not observed in anxious depression. LIMITATIONS: The present study did not include an anxiety-only group for comparison, and did not assess state anxiety at time of administration. In addition, the extent to which the experimental task correlates with social functioning is not fully understood. CONCLUSIONS: These findings suggest a diminished sensitivity to happy and sad facial expressions specific to anxious depression, but not a hypervigilance toward threatening facial expressions. Further research on the nature of emotion recognition in anxiety and depression may inform improved clinical interventions.

Depressive Symptoms and Suicidal Ideation in College Students: The Mediating and Moderating Roles of Hopelessness, Alcohol Problems, and Social Support.

OBJECTIVE: Mixed evidence for the associations among depression, hopelessness, alcohol problems, and suicidal ideation in college students may be due to the influence of social support. METHOD: A moderated-mediation analysis was conducted to examine relationships among suicide risk factors in 2,034 college students. RESULTS: Social support moderated the relation between depressive symptoms and hopelessness in predicting suicidal thoughts; specifically, the association between depressive symptoms and hopelessness was diminished among those students with high levels of social support. This resulted in attenuated indirect associations between depressive symptoms and suicidal ideation via hopelessness. Alcohol problems were associated with likelihood of experiencing suicidal ideation, but not severity. CONCLUSION: Social support may be a key variable for suicide prevention among college students.

Lithium and Valproate Levels Do Not Correlate with Ketamine's Antidepressant Efficacy in Treatment-Resistant Bipolar Depression.

Ketamine and lithium both inhibit glycogen synthase kinase 3. In addition, lithium and ketamine have synergistic antidepressant-like effects at individually subeffective doses in rodents. We hypothesized that ketamine's antidepressant effects would be improved by therapeutic doses of lithium versus valproate and that serum lithium levels would positively correlate with ketamine's antidepressant efficacy. Thirty-six patients with treatment-resistant bipolar depression maintained on therapeutic-dose lithium (n = 23, 0.79 ± 0.15 mEq/L) or valproate (n = 13, 79.6 ± 12.4 mg/mL) received 0.5 mg/kg ketamine infusion in a randomized, double-blind, placebo-controlled, crossover trial. The primary depression outcome measure-the Montgomery-Åsberg Depression Rating Scale (MADRS)-was assessed before infusion and at numerous postinfusion time points. Both lithium (F 1,118 = 152.08, p < 0.001, and d = 2.27) and valproate (F 1,128 = 20.12, p < 0.001, and d = 0.79) significantly improved depressive symptoms, but no statistically significant difference was observed between mood stabilizer groups (F 1,28 = 2.51, p = 0.12, and d = 0.60). Serum lithium and valproate levels did not correlate with ketamine's antidepressant efficacy. Although the study was potentially underpowered, our results suggest that lithium may not potentiate ketamine's antidepressant efficacy in treatment-resistant bipolar depression.

Parent-child conflict and drug use in college women: a moderated mediation model of self-control and mindfulness.

This cross-sectional study examined the association between parent-child conflict and illicit drug use in a sample of female college students (N = 928). The mediating roles of self-control and mindfulness, as well as an interaction between self-control and mindfulness, were examined in a moderated mediation model for the purposes of expanding etiological theory and introducing targets for the prevention and treatment of drug abuse. Whereas deficits in self-control were found to facilitate the positive relation observed between parent-child conflict and the likelihood of experiencing drug-related problems, an interaction between mindfulness and self-control helped explain the association between parent-child conflict and intensity of drug-related problems. Parent-child conflict was related to low mindfulness when self-control was low, and low mindfulness in turn was related to a higher intensity of drug-related problems. This association did not exist for women with high self-control. Findings are consistent with developmental research on the etiology of drug use and the protective properties of mindfulness and self-control. Mindfulness as a potential target of intervention for drug users with low self-control to prevent drug-related problems is explored.

Self-harm, Assault, and Undetermined Intent Injuries Among Pediatric Emergency Department Visits.

OBJECTIVES: Although injuries are a known cause of morbidity and mortality among children and adolescents, little is known about the epidemiology of injury-related emergency department (ED) visits in the United States by injury intent. The objective of this analysis was to examine ED outcomes, defined as death in the ED, inpatient admission, and visit cost, among ED visits stratified by injury intent (i.e., self-harm, assault, and injury with undetermined intent, as compared with unintentional injuries). METHODS: All injury-related ED visits in the United States for children and adolescents, ages 8 to 17 years, were identified using the 2008 Nationwide Emergency Department Sample. Multivariate survey weighted logistic and linear regression analyses were then used to estimate the likelihood of death on ED visit, inpatient admission, and cost across the 4 injury types. RESULTS: In 2008, with the use of weighted estimates, there were 66,895 self-harm, 176,125 assault, 24,144 undetermined injury, and 4,244,589 unintentional injury ED visits among children 8 to 17 years. Visits due to self-harm, assault and undetermined injuries were more likely to result in death during the ED visit compared with visits due to unintentional injuries. Self-harm and undetermined intent were also associated with greater odds of inpatient admission as well as 90% and 60% higher ED visit costs, respectively. CONCLUSIONS: Data from this nationwide sample of pediatric ED visits highlight the resource burden of self-harm, undetermined intent, and assault injury visits. Pediatric EDs may provide a window of opportunity for better case identification and intervention with children experiencing violence and injury.

Neural correlates of suicidal ideation and its reduction in depression.

BACKGROUND: The neural correlates of suicidal ideation and its reduction after treatment are unknown. We hypothesized that increased regional cerebral glucose metabolism in the infralimbic cortex (Brodmann area 25), amygdala, and subgenual anterior cingulate cortex would be associated with suicidal ideation and its reduction after ketamine infusion. METHODS: Medication-free patients (n=19) with treatment-resistant major depressive disorder underwent positron emission tomography imaging at baseline and 230 minutes after an open-label ketamine infusion (0.5 mg/kg for 40 minutes). RESULTS: Baseline suicidal ideation and regional cerebral glucose metabolism in the infralimbic cortex were significantly correlated (r=.59, P=.007); but not overall mood scores (r=-.07, P=.79). Reductions in suicidal ideation after ketamine infusion were correlated with decreased regional cerebral glucose metabolism in the infralimbic cortex (r=.54, P=.02). Metabolism in other areas of interest was not significantly correlated with suicidal ideation or depression. CONCLUSION: The infralimbic cortex may be implicated in suicidal ideation.