The glutamate N-methyl-D-aspartate receptor antagonist ketamine has demonstrated antidepressant effects in individuals with treatment-resistant major depressive disorder (TRD) within 24 h of a single dose. The current study utilized functional magnetic resonance imaging (fMRI) and two separate emotion perception tasks to examine the neural effects of ketamine in patients with TRD. One task used happy and neutral facial expressions; the other used sad and neutral facial expressions. Twenty patients with TRD free of concomitant antidepressant medication underwent fMRI at baseline and 24 h following administration of a single intravenous dose of ketamine (0.5 mg kg−1). Adequate data were available for 18 patients for each task. Twenty age- and sex-matched healthy volunteers were scanned at one time point for baseline comparison. Whole-brain, voxel-wise analyses were conducted controlling for a family-wise error rate (FWE) of P<0.05. Compared with healthy volunteers, TRD patients showed reduced neural responses to positive faces within the right caudate. Following ketamine, neural responses to positive faces were selectively increased within a similar region of right caudate. Connectivity analyses showed that greater connectivity of the right caudate during positive emotion perception was associated with improvement in depression severity following ketamine. No main effect of group was observed for the sad faces task. Our results indicate that ketamine specifically enhances neural responses to positive emotion within the right caudate in depressed individuals in a pattern that appears to reverse baseline deficits and that connectivity of this region may be important for the antidepressant effects of ketamine.

ObjectiveTo quantify the type, prevalence, and cost of imaging following inpatient falls, identify factors associated with post-fall imaging, and determine correlates of positive versus negative imaging.DesignSingle-center retrospective cohort study of inpatient falls. Data were collected from the hospital’s adverse event reporting system, DrQuality. Age, sex, date, time, and location of fall, clinical service, Morse Fall Scale/fall protocol, admitting diagnosis, and fall-related imaging studies were reviewed. Cost included professional and facilities fees for each study.SettingFour hundred and fifteen bed urban academic hospital over 3 years (2008–2010).PatientsAll adult inpatient falls during the study period were included. Falls experienced by patients aged <18 years, outpatient and emergency patients, visitors to the hospital, and staff were excluded.Measurements and main resultsFive hundred and thirty inpatient falls occurred during the study period, average patient age 60.7 years (range 20–98). More than half of falls were men (55%) and patients considered at risk of falls (56%). Falls were evenly distributed across morning (33%), evening (34%), and night (33%) shifts. Of 530 falls, 178 (34%) patients were imaged with 262 studies. Twenty percent of patients imaged had at least one positive imaging study attributed to the fall and 82% of studies were negative. Total cost of imaging was $160,897, 63% ($100,700) from head computed tomography (CT).ConclusionInpatient falls affect patients of both sexes, all ages, occur at any time of day and lead to expensive imaging, mainly from head CTs. Further study should be targeted toward clarifying the indications for head CT after inpatient falls and validating risk models for positive and negative imaging, in order to decrease unnecessary imaging and thereby limit unnecessary cost and radiation exposure.

Further investigation will be needed to determine whether naltrexone is efficacious among depressed alcohol dependent patients and whether naltrexone and antidepressant medications show interactive efficacy for treating alcohol dependence.

No abstract

Limited knowledge exists regarding the neurobiology of suicidal thoughts, given that there are currently no direct probes of the suicidal state. This pilot study used magnetoencephalography (MEG) to evaluate correlates of the implicit association between the self and death compared to the self and life as objective markers of suicide risk. Healthy volunteers (HVs; n=21) completed a modified version of the Suicide Implicit Association Task (S-IAT) during MEG scanning. Gamma power-which is considered a proxy measure of excitation-inhibition balance-was directly compared in the self-death/self-life contrast. As a proof-of-concept, the ability of dynamic causal modeling to categorize HVs versus four individuals with recent suicide crisis (SC) was evaluated. In HVs, enhanced gamma power in both amygdala and anterior insula were found for the self-death compared with self-life contrast. In addition, connectivity estimates between early visual cortex, anterior insula, and amygdala correctly categorized SC participants with 77% to 82% sensitivity and 80% to 85% specificity. These findings, which implicate network-level changes in salience network and amygdala connectivity in mediating suicidal associations, require further replication in larger samples. Direct probing of suicidal thoughts with the S-IAT may provide foundational markers of neural circuits associated with suicide risk.