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Background Our lab has previously found that structural integrity in tracts from the raphe nucleus (RN) to the amygdala, measured by fractional anisotropy (FA), predicts remission to selective serotonin reuptake inhibitors (SSRIs) in major depressive disorder (MDD). This could potentially serve as a biomarker for remission that can guide clinical decision-making. To enhance repeatability and reproducibility, we replicated our study in a larger, more representative multi-site sample. Methods 64 direction DTI was collected in 144 medication-free patients with MDD from the Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care (EMBARC) study. We performed probabilistic tractography between the RN and bilateral amygdala and hippocampus and calculated weighted FA in these tracts. Patients were treated with either sertraline or placebo, and their change in Hamilton Depression Rating Scale (HDRS) score reported. Pretreatment weighted FA was compared between remitters and nonremitters, and correlation between FA and percent change in HDRS score was assessed. Exploratory moderator and voxel analyses were also performed. Results Contrary to our hypotheses, FA was greater in nonremitters than in remitters in RN-left and right amygdala tracts (p = 0.02 and 0.01, respectively). Pretreatment FA between the raphe and left amygdala correlated with greater, not reduced, HDRS (r = 0.18, p = 0.04). This finding was found to be greater in the placebo group. Moderator and voxel analyses yielded no significant findings. Conclusions We found greater FA in nonremitters between the RN and amygdala than in remitters, and a correlation between FA and symptom worsening, particularly with placebo. These findings may help reveal more about the nature of MDD, as well as guide research methods involving placebo response.

BACKGROUND: Despite the fact that higher levels of anxiety and anhedonia in Major Depressive Disorder (MDD) are linked to poorer treatment outcomes, mechanisms contributing to these clinical presentations remain unclear. Neuroticism, impaired cognitive control, and blunted reward learning may be critical processes involved in MDD and may help to explain symptoms of anxiety and anhedonia. METHODS: Using baseline data from patients with early-onset MDD (N=296) in the Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC) trial, we conducted a path analysis to model relationships between neuroticism, cognitive control, and reward learning to levels of anxiety and anhedonia. RESULTS: Neuroticism was positively associated with both anhedonia (standardized coefficient = 0.26, p < .001) and anxiety (standardized coefficient = 0.40, p < .001). Cognitive control was negatively associated with anxiety (standardized coefficient = −0.18, p < .05). Reward learning was not significantly associated with either anxiety or anhedonia. LIMITATIONS: Extraneous variables not included in the model may have even more influence in explaining symptoms of anxiety and anhedonia. Restricted range in these variables may have attenuated some of the hypothesized relationships. Most important, because this was a cross-sectional analysis in a currently depressed sample, we cannot draw any causal conclusions without experimental and longitudinal data. CONCLUSIONS: These cross-sectional findings suggest that neuroticism may contribute to anxiety and anhedonia in patients with early onset and either chronic or recurrent MDD, while enhanced cognitive control may protect against anxiety.

Background The lower-expressing (S′) alleles of the serotonin transporter (5-HTT) gene promoter polymorphism (5-HTTLPR) are linked to mood and anxiety related psychopathology. However, the specific neural mechanism through which these alleles may influence emotional and cognitive processing remains unknown. We examined the relationship between both 5-HTTLPR genotype and in vivo 5-HTT binding quantified via PET with amygdala reactivity to emotionally negative stimuli. We hypothesized that 5-HTT binding in both raphe nuclei (RN) and amygdala would be inversely correlated with amygdala reactivity, and that number of S′ alleles would correlate positively with amygdala reactivity. Methods In medication-free patients with current major depressive disorder (MDD; N =21), we determined 5-HTTLPR genotype, employed functional magnetic resonance imaging (fMRI) to examine amygdala responses to negative emotional stimuli, and used positron emission tomography with [ 11 C]DASB to examine 5-HTT binding. Results [ 11 C]DASB binding in RN and amygdala was inversely correlated with amygdala response to negative stimuli. 5-HTTLPR S′ alleles were not associated with amygdala response to negative emotional stimuli. Limitations Primary limitations are small sample size and lack of control group. Conclusions Consistent with findings in healthy volunteers, 5-HTT binding is associated with amygdala reactivity to emotional stimuli in MDD. 5-HTT binding may be a stronger predictor of emotional processing in MDD as compared with 5-HTTLPR genotype.

We compared brain-map correlations of relative cerebral glucose metabolism (rCMRglu) with psychopathologic factors derived from the self-rated Beck Depression Inventory (BDI) and factors from the clinician-rated Hamilton Depression Rating Scale (HDRS) factors, seeking an anatomic basis for differences in self and clinician ratings.[(18)F]-FDG Positron Emission Tomography generated rCMRglu, SPM-estimated, voxel-level, brain correlation maps with BDI factor scores and HDRS factor scores in medication-free major depressive disorder.Regional brain correlates of BDI are more extensive than HDRS, even when adjusting for variance accounted for by the HDRS. Factors comprising the BDI were associated with distinct cortical and subcortical regions. The degree of overlap in factor correlation brain maps is explained by the variance shared by BDI and HDRS factor scores.Self and clinician-rated aspects of depression have common and distinct neuroanatomic correlates that reflect correlations between rating scales, but correlations between glucose metabolism and self-rated depression were anatomically more extensive in this sample. Findings highlight the importance and biological underpinnings of these subjective features of major depression.

Background Bipolar disorder (BD) is associated with a high prevalence of suicide attempt and completion. Family history of suicidal behavior and personal history of childhood abuse are reported risk factors for suicide among BD subjects. Methods BD individuals with family history of suicidal behavior and personal history of childhood abuse (BD-BOTH), BD individuals with family history of suicidal behavior or personal history of childhood abuse (BD-ONE), and BD individuals with neither of these two risk factors (BD-NONE) were compared with regard to demographic variables and clinical measures. Results Almost 70% of the sample had a history of a previous suicide attempt. There were significantly higher rates of previous suicide attempts in the BD-BOTH and BD-ONE relative to the BD-NONE group. BD-BOTH were significantly younger at the time of their first suicide attempt and had higher number of suicide attempts compared with BD-NONE. BD-BOTH were significantly younger at the time of their first episode of mood disorder and first psychiatric hospitalization and had significantly higher rates of substance use and borderline personality disorders compared to BD-NONE. Limitations Retrospective study. Use of semi-structured interview for the assessment of risk factors. Conclusions BD individuals with a familial liability for suicidal behavior and exposed to physical and/or sexual abuse during childhood are at a greater risk to have a more impaired course of bipolar illness and greater suicidality compared to those subjects with either only one or none of these risk factors. Prospective studies are needed to confirm these findings.

Background Defining bipolar disorder (BD) subtypes with increased risk of suicidal behavior may help clinical management. We tested the hypothesis that the polarity of a patient's first mood episode would be a marker for BD subtypes with differential risk for suicidality. Methods One hundred thirteen subjects with DSM-IV defined BD were classified based on whether their first reported episode was manic/hypomanic (FM) or depressed (FD). They were compared on demographic and clinical variables. Logistic regression adjusting for potential confounds tested the association between first episode polarity and history of suicide attempt. Results Multiple logistic regression analysis showed that FD group membership was associated with eightfold odds of a past suicide attempt, adjusting for years ill and total number of lifetime major depressive episodes. Limitations Sample size, retrospective design, recall bias, assessment during a mood episode, and imprecise recall of hypomania. Conclusions Polarity of patients' first reported mood episode suggested a depression-prone subtype with a greater probability of past suicide attempt. The FM group had more alcoholism and psychosis, but less likelihood of past suicide attempt. Validation of these putative subtypes requires prospective study.

Background : Positron Emission Tomography (PET) studies have reported altered resting regional brain glucose metabolism in mood disorders. This study examines the relationship of such changes to serotonin system abnormalities associated with depression. Methods : Thirteen male medication free subjects who were inpatients with a DSM-IIIR major depressive disorder and seven healthy male subjects underwent an [ 18 F]-fluorodeoxyglucose ( 18 FDG) PET scan on consecutive days. Three hours prior to 18 FDG subjects received single blind placebo or fenfluramine. Comparisons of voxel level regional glucose metabolic rate responses (rCMRglu) between groups in the two states were performed with SPM99. Results : Unlike healthy male subjects who have significant increases in rCMRglu in prefrontal and parietal cortical regions after receiving fenfluramine, depressed male subjects have no significant increases in rCMRglu. Conclusions : Blunted increases in rCMRglu in response to fenfluramine in prefrontal and parietal cortex are consistent with our previous pilot study and the indoleamine hypothesis of depression. Differences in specific brain regions affected between this study and previous studies may be attributable to gender differences.