Faculty Bibliography

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.

OBJECTIVE: Ketamine has demonstrated rapid antidepressant effects in patients with treatment-resistant depression (TRD); however, the safety and tolerability of ketamine in this population have not been fully described. Herein we report the largest study to date of the safety, tolerability, and acceptability of ketamine in TRD. METHOD: Data from 205 intravenous (IV) ketamine infusions (0.5 mg/kg over 40 minutes) in 97 participants with DSM-IV-defined major depressive disorder (MDD) were pooled from 3 clinical trials conducted between 2006 and 2012 at 2 academic medical centers. Safety and tolerability measures included attrition, adverse events (AEs), hemodynamic changes, and assessments of psychosis and dissociation. RESULTS: The overall antidepressant response rate, defined as a >/= 50% improvement in Montgomery-Asberg Depression Rating Scale score, was 67% (65 of 97 participants). Four of 205 infusions (1.95%) were discontinued due to AEs. The overall attrition rate was 3.1% (3 of 97). In the first 4 hours after the infusion, the most common general AEs were drowsiness, dizziness, poor coordination, blurred vision, and feeling strange or unreal. Approximately one third of individuals experienced protocol-defined hemodynamic changes. Ketamine resulted in small but significant increases in psychotomimetic and dissociative symptoms (all P < .05). There were no cases of persistent psychotomimetic effects, adverse medical effects, or increased substance use in a subgroup of patients with available long-term follow-up information. CONCLUSIONS: In this relatively large group of patients with TRD, ketamine was safe and well tolerated. Further research investigating the safety of ketamine in severe and refractory depression is warranted. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT00419003, NCT00548964, and NCT00768430.

OBJECTIVES: Treatment-resistant depression is a common clinical occurrence among patients with major depressive disorder (MDD), but its neurobiology is poorly understood. We used data collected as part of routine clinical care to study white matter integrity of the brain's limbic system and its association to treatment response. METHODS: Electronic medical records of multiple large New England hospitals were screened for patients with an MDD billing diagnosis, and natural language processing was subsequently applied to find those with concurrent diffusion-weighted images, but without any diagnosed brain pathology. Treatment outcome was determined by review of clinical charts. MDD patients (n = 29 non-remitters, n = 26 partial-remitters, and n = 37 full-remitters), and healthy control subjects (n = 58) were analyzed for fractional anisotropy (FA) of the fornix and cingulum bundle. RESULTS: Failure to achieve remission was associated with lower FA among MDD patients, statistically significant for the medial body of the fornix. Moreover, global and regional-selective age-related FA decline was most pronounced in patients with treatment-refractory, non-remitted depression. CONCLUSIONS: These findings suggest that specific brain microstructural white matter abnormalities underlie persistent, treatment-resistant depression. They also demonstrate the feasibility of investigating white matter integrity in psychiatric populations using legacy data.

OBJECTIVE: This study examined general medical illnesses and their association with clinical features of bipolar disorder. METHOD: Data were cross-sectional and derived from the Lithium Treatment - Moderate Dose Use Study (LiTMUS), which randomized symptomatic adults (n = 264 with available medical comorbidity scores) with bipolar disorder to moderate doses of lithium plus optimized treatment (OPT) or to OPT alone. Clinically significant high and low medical comorbidity burden were defined as a Cumulative Illness Rating Scale (CIRS) score >/=4 and <4 respectively. RESULTS: The baseline prevalence of significant medical comorbidity was 53% (n = 139). Patients with high medical burden were more likely to present in a major depressive episode (P = .04), meet criteria for obsessive-compulsive disorder (P = .02), and experience a greater number of lifetime mood episodes (P = 0.02). They were also more likely to be prescribed a greater number of psychotropic medications (P = .002). Sixty-nine per cent of the sample was overweight or obese as defined by body mass index (BMI), with African Americans representing the racial group with the highest proportion of stage II obesity (BMI >/=35; 31%, n = 14). CONCLUSION: The burden of comorbid medical illnesses was high in this generalizable sample of treatment-seeking patients and appears associated with worsened course of illness and psychotropic medication patterns.

OBJECTIVE: Late-life depression has been hypothesized to have a neurodegenerative component that leads to impaired executive function and increases in subcortical white matter hyperintensities. Phosphorus magnetic resonance spectroscopy (MRS) can quantify several important phosphorus metabolites in the brain, particularly the anabolic precursors and catabolic metabolites of the constituents of cell membranes, which could be altered by neurodegenerative activity. METHODS: Ten patients with late-life major depression who were medication free at time of study and 11 aged normal comparison subjects were studied using (31)P MRS three-dimensional chemical shift imaging at 4 Tesla. Phosphatidylcholine and phosphatidylethanolamine comprise 90% of cell membranes in brain but cannot be quantified precisely with (31)P MRS. We measured phosphocholine and phosphoethanolamine, which are anabolic precursors, as well as glycerophosphocholine and glycerophosphoethanolamine, which are catabolic metabolites of phosphatidylcholine and phosphatidylethanolamine. RESULTS: In accordance with our hypotheses, glycerophosphoethanolamine was elevated in white matter of depressed subjects, suggesting enhanced breakdown of cell membranes in these subjects. Glycerophosphocholine did not show any significant difference between comparison and depressed subjects but both showed an enhancement in white matter compared with gray matter. Contrary to our hypotheses, neither phosphocholine nor phosphoethanolamine showed evidence for reduction in late-life depression. CONCLUSION: These findings support the hypothesis that neurodegenerative processes occur in white matter in patients with late-life depression more than in the normal elderly population.

This study was designed to identify genes whose expression in peripheral blood may serve as early markers for treatment response to lithium (Li) in patients with bipolar disorder. Although changes in peripheral blood gene-expression may not relate directly to mood symptoms, differences in treatment response at the biochemical level may underlie some of the heterogeneity in clinical response to Li. Subjects were randomized to treatment with (n=28) or without (n=32) Li. Peripheral blood gene-expression was measured before and 1 month after treatment initiation, and treatment response was assessed after 6 months. In subjects treated with Li, 62 genes were differentially regulated in treatment responders and non-responders. Of these, BCL2L1 showed the greatest difference between Li responders and non-responders. These changes were specific to Li responders (n=9), and were not seen in Li non-responders or patients treated without Li, suggesting that they may have specific roles in treatment response to Li.

BACKGROUND: Efficacy-based double-blind placebo controlled trials were conducted to establish efficacy and safety for FDA approval. Such designs allowed and encouraged the use of exclusion criteria to improve assay sensitivity and internal validity. The LiTMUS trial increased the representation of real-world individuals with bipolar disorder despite the acknowledgment that this compromises assay sensitivity. METHOD: To maximize generalizability, LiTMUS used broad inclusion and narrow exclusion criteria: participants experiencing mood symptoms of sufficient intensity (at least with a CGI-BP >/= 3) that would warrant a change in treatment, and that lithium treatment would be a reasonable therapeutic option if they were randomized to it. At baseline demographic, illness, clinical, and treatment characteristics were collected. The LiTMUS study design and baseline sociodemographic data were compared to previous efficacy studies. RESULTS: As compared to the previous bipolar disorder efficacy studies, LiTMUS participants were of similar age, gender, weight and illness severity; however LiTMUS participants were more racially and ethnically representative of the general population, had a greater number of mood episodes in the past 12 months, more Axis I/II comorbidity, a greater number of prior suicide attempts, and higher functional capacity. CONCLUSIONS: LiTMUS was a comparative effectiveness trial that had broad inclusion and minimal exclusion criteria that produced a more representative sample comprised of real-world participants. This design enables the results of the LiTMUS study to be a more representative of real world pharmacotherapuetic outcomes. LIMITATIONS: Limitations include possible selection bias, paucity of sociodemographic data in efficacy trials, and lack of a placebo.

OBJECTIVE: Psychopharmacology remains the foundation of treatment for bipolar disorder, but medication adherence in this population is low (range 20-64%). We examined medication adherence in a multisite, comparative effectiveness study of lithium. METHOD: The Lithium Moderate Dose Use Study (LiTMUS) was a 6-month, six-site, randomized effectiveness trial of adjunctive moderate dose lithium therapy compared with optimized treatment in adult out-patients with bipolar I or II disorder (N=283). Medication adherence was measured at each study visit with the Tablet Routine Questionnaire. RESULTS: We found that 4.50% of participants reported missing at least 30% of their medications in the past week at baseline and non-adherence remained low throughout the trial (<7%). Poor medication adherence was associated with more manic symptoms and side-effects as well as lower lithium serum levels at mid- and post-treatment, but not with poor quality of life, overall severity of illness, or depressive symptoms. CONCLUSION: Participants in LiTMUS were highly adherent with taking their medications. The lack of association with possible predictors of adherence, such as depression and quality of life, could be explained by the limited variance or other factors as well as by not using an objective measure of adherence.

OBJECTIVES: Motivated by genetic association data implicating L-type calcium channels in bipolar disorder liability, we sought to estimate the tolerability, safety, and efficacy of isradipine in the adjunctive treatment of bipolar depression. METHODS: A total of 12 patients with bipolar I or II depression entered this pilot, proof-of-concept eight-week investigation and 10 returned for at least one post-baseline visit. They were initiated on isradipine at 2.5 mg and titrated up to 10 mg daily, with blinded assessments of depression using the Montgomery-Asberg Depression Rating Scale (MADRS) as well as adverse effects. RESULTS: Among the 10 patients, three had bipolar II disorder; all but two reported current episode duration longer than six months. In all, four of 10 completed the study; no significant adverse events were observed, although one subject discontinued treatment per protocol because of possible hypomanic symptoms which had resolved prior to study visit. In a mixed-effects model, mean improvement in depression severity, assessed by MADRS, was 2.1 (standard error = 0.36) points/week (p < 0.001). Two of the 10 subjects remitted and four of the 10 subjects experienced 50% or greater symptomatic improvement with treatment. CONCLUSIONS: Isradipine merits further investigation for the treatment of bipolar depression. This preliminary trial illustrates the potential utility of genetic investigation in identifying psychiatric treatment targets.

BACKGROUND: While antidepressant treatment response appears to be partially heritable, no consistent genetic associations have been identified. Large, rare copy number variants (CNVs) play a role in other neuropsychiatric diseases, so we assessed their association with treatment-resistant depression (TRD). METHODS: We analyzed data from two genome-wide association studies comprising 1263 Caucasian patients with major depressive disorder. One was drawn from a large health system by applying natural language processing to electronic health records (i2b2 cohort). The second consisted of a multicenter study of sequential antidepressant treatments, Sequenced Treatment Alternatives to Relieve Depression. The Birdsuite package was used to identify rare deletions and duplications. Individuals without symptomatic remission, despite two antidepressant treatment trials, were contrasted with those who remitted with a first treatment trial. RESULTS: CNV data were derived for 778 subjects in the i2b2 cohort, including 300 subjects (37%) with TRD, and 485 subjects in Sequenced Treatment Alternatives to Relieve Depression cohort, including 152 (31%) with TRD. CNV burden analyses identified modest enrichment of duplications in cases (empirical p = .04 for duplications of 100-200 kilobase) and a particular deletion region spanning gene PABPC4L (empirical p = .02, 6 cases: 0 controls). Pathway analysis suggested enrichment of CNVs intersecting genes regulating actin cytoskeleton. However, none of these associations survived genome-wide correction. CONCLUSIONS: Contribution of rare CNVs to TRD appears to be modest, individually or in aggregate. The electronic health record-based methodology demonstrated here should facilitate collection of larger TRD cohorts necessary to further characterize these effects.