Neural functional connectivity changes to psychosocial stress in young adults with bipolar disorder and preliminary associations with clinical trajectories.

BACKGROUND: Stress-related mechanisms are implicated in the pathophysiology of bipolar disorder and may contribute to heterogeneity in illness course. Yet, there is a lack of study investigating the neural mechanisms underlying the stress response in this condition. This study investigated changes in amygdala activation and functional connectivity in response to acute psychosocial stress in young adults with bipolar disorder and explored relations with clinical phenotype and prospective mood symptoms. METHODS: 42 young adults [19 with bipolar disorder, agemean  ± SD =21.4 ± 2.2 years] completed a modified version of the Montreal Imaging Stress Task. Amygdala activation and functional connectivity with prefrontal cortex (PFC) regions of interest was calculated for control and stress conditions. Main effects of group, condition, and group by condition interaction on amygdala activation and connectivity were modeled. A subset of bipolar participants completed 1-year follow-up assessments. Relations between neural responses to stress with concurrent substance use and prospective mood symptoms were explored. RESULTS: There were no between-group differences in amygdala activation or functional connectivity during the control condition. Increased right amygdala-right rostral PFC (rPFC) functional connectivity to stress was observed in bipolar disorder, compared to typically developing controls. In bipolar disorder, greater increase in right amygdala-right rPFC functional connectivity to stress was associated with less frequent cannabis use, and prospectively with shorter duration and lower severity of depression symptoms over follow-up. CONCLUSION: Results from this preliminary study suggest differences in frontolimbic functional connectivity responses to stress in young adults with bipolar disorder and associations with cannabis use and prospective mood symptoms.

Variation in rostral anterior cingulate functional connectivity with amygdala and caudate during first manic episode distinguish bipolar young adults who do not remit following treatment.

OBJECTIVES: Altered activity in the ventrolateral prefrontal and anterior cingulate cortices, as well as subcortical and amygdala projection sites, was previously reported during a first manic episode in youth with bipolar disorder and observed to be associated with treatment response. To extend these findings, we investigated functional connectivity among these regions in first-episode manic participants who remitted after 8 weeks of treatment compared to those who did not. METHODS: Forty-two participants with bipolar disorder (60% female) during their first manic episode were recruited and received 8 weeks of treatment. Twenty-one remitted following treatment. Participants completed fMRI scans, at baseline and following 8 weeks of treatment, while performing a continuous performance task with emotional and neutral distractors. A healthy comparison group (n = 41) received fMRI evaluations at the same intervals. Differences in functional connectivity of the amygdala and caudate with the rostral anterior cingulate and ventrolateral prefrontal cortices at baseline (and changes in functional connectivity following treatment) were modeled between groups. RESULTS: At baseline, non-remitters showed an increase in positive connectivity between right anterior cingulate and caudate and a loss of negative connectivity between right anterior cingulate and amygdala, compared to healthy participants. Individuals who remitted following treatment showed an increase in negative connectivity between amygdala and left anterior cingulate 8 weeks following treatment. CONCLUSIONS: Results provide evidence of alterations in anterior cingulate amygdala and caudate functional connectivity in bipolar disorder non-remitters during a first manic episode and changes in anterior cingulate functional connectivity associated with remission suggesting targets to predict treatment response. Registered at ClinicalTrials.Gov; Functional and Neurochemical Brain Changes in First-episode Bipolar Mania. NCT00609193. URL: https://clinicaltrials.gov/ct2/show/NCT00609193?term=strakowskirank=1.

Longitudinal proton spectroscopy study of the prefrontal cortex in youth at risk for bipolar disorder before and after their first mood episode.

OBJECTIVES: To investigate neurochemical abnormalities in the left and right ventrolateral prefrontal cortex (VLPFC) and anterior cingulate cortex (ACC) of youth at risk for bipolar disorder using proton magnetic resonance spectroscopy before and after their first mood episode. METHODS: Children and adolescents offspring of parents with bipolar I disorder (at-risk group, n = 117) and matched healthy controls (HC group, n = 61) were recruited at the University of Cincinnati. At-risk subjects had no lifetime major mood and psychotic disorders at baseline, and were followed up every 4 months to monitor for development of a major depressive, manic, hypomanic, or mixed mood episode. Levels of N-acetyl-aspartate (NAA), phosphocreatine plus creatine (PCr + Cr), choline-containing compounds, myo-inositol, and glutamate were determined using LCModel and corrected for partial volume effects. RESULTS: There were no baseline differences in metabolite levels for any of the brain regions between at-risk and HC youth. Nineteen at-risk subjects developed a first mood episode during follow-up. Survival analyses showed that baseline PCr + Cr levels in the left VLPFC significantly predicted a mood episode during follow-up in the at-risk group (HR: 0.47, 95% CI: 0.27-0.82, P = 0.008). There were no longitudinal changes in metabolites levels in the VLPFC and ACC before and after a mood episode in at-risk subjects. CONCLUSIONS: We found no evidence for abnormal proton spectroscopy metabolite levels in the VLPFC and ACC of at-risk youth, prior and after the development of their first mood episode. Preliminary findings of association between baseline PCr + Cr levels in the left VLPFC and risk to develop a mood episode warrant further investigation.

Neurophysiological effects of multiple mood episodes in bipolar disorder.

OBJECTIVES: Bipolar disorder is marked by progressive symptomatic changes, which have been linked with episode-related structural findings-particularly in the prefrontal cortex. However, few studies have examined neurofunctional and neurochemical effects of disease burden. In this study, we compared first- and multi-episode bipolar individuals. We hypothesized that the latter would demonstrate evidence of neurophysiological differences consistent with a model of progressive functional degradation of these networks. METHODS: First- and multi-episode manic bipolar subjects participated in functional magnetic resonance imaging (fMRI) including a continuous performance task with emotional distractors, and in single-voxel (1 H) magnetic resonance spectroscopy (MRS). A priori fMRI regions-of-interest (ROI) included structures comprising prefrontal-striatal-amygdala networks; (1 H)MRS voxels were placed within bilateral ventrolateral prefrontal (VLPFC) and anterior cingulate cortex (ACC). Both ROI and voxel-based brain activation in response to emotional stimuli, and neurochemical concentrations derived from (1 H)MRS were compared across bipolar groups. RESULTS: Multi-episode bipolar subjects showed relatively lower regional activation across prefrontal-striatal-amygdala networks, including bilateral VLPFC, orbitofrontal cortex, ACC, putamen, caudate, and amygdala. Exploratory whole-brain, voxel-based analysis suggested additional areas of lower activation extending into Brodmann area 22, posterior parietal regions, and right thalamus. Glutamate and N-acetylaspartate (NAA) concentrations were also relatively lower in the ACC of multi-episode subjects. CONCLUSIONS: Disease burden, exemplified by multiple affective episodes is associated with evidence of widespread decrements in affective network activity. Lower ACC NAA concentration is similarly consistent with a model of progressive functional deficits. These findings support the functional significance of previously observed progressive structural changes throughout these regions.

MRI Evidence of Neuropathic Changes in Former College Football Players.

OBJECTIVE: To examine effects of participating in collegiate football on neural health several years after retirement. We hypothesized that relative cortical thinning and loss of white matter integrity would be observed in former players. DESIGN: Former NCAA Division I football players were compared with demographically similar track-and-field athletes with regard to cortical thickness and white matter integrity. SETTING: Participants participated in MRI scans at the Center for Imaging Research at the University of Cincinnati. PARTICIPANTS: Eleven former football players and 10 demographically similar track-and-field athletes. MAIN OUTCOME MEASURES: Normalized cortical thickness was compared between groups using 2-tailed Student t test. As a secondary analysis, Spearman correlation coefficient was calculated between cortical thickness and number of concussions. Fractional anisotropy for regions-of-interest placed in frontal white matter tracts and internal capsule were compared between groups using 2-tailed Student t test. RESULTS: Football players showed significantly lower cortical thickness within portions of both the frontal and temporal cortex. Affected frontal regions included left frontal pole and right superior frontal gyrus. Affected temporal regions included portions of the superior temporal gyrus, left inferior temporal gyrus, and right middle and superior temporal gyri. Cortical thickness inversely correlated with number of reported concussions over most of these regions. In addition, fractional anisotropy was lower in the right internal capsule of former football players, relative to controls. CONCLUSIONS: These findings suggest that at least some consequences of high-level collegiate football play persist even after the cessation of regular head blows. Longer-term studies are warranted to examine potential cognitive and functional implications of sustained cortical atrophy.

Docosahexaenoic acid biostatus is associated with event-related functional connectivity in cortical attention networks of typically developing children.

OBJECTIVE: Although extant preclinical evidence suggests that the long-chain omega-3 fatty acid docosahexaenoic acid (DHA) is important for neurodevelopment, little is known about its role in human cortical structural and functional maturation. In the present cross-sectional study, we investigated the relationship between DHA biostatus and functional connectivity in cortical attention networks of typically developing children. METHODS: Male children (aged 8-10 years, n = 36) were divided into 'low-DHA' (n = 18) and 'high-DHA' (n = 18) biostatus groups by a median split of erythrocyte DHA levels. Event-related functional connectivity during the performance of a sustained attention task (identical pairs continuous performance task (CPT-IP)) was conducted using functional magnetic resonance imaging. A voxelwise approach used the anterior cingulate cortex (ACC) as the seed-region. RESULTS: Erythrocyte DHA composition in the low-DHA group (2.6 ± 0.9%) was significantly lower than the high-DHA group (4.1 ± 1.1%, P ≤ 0.0001). Fish intake frequency was greater in the high-DHA group (P = 0.003) and was positively correlated with DHA levels among all subjects. The low-DHA group exhibited reduced functional connectivity between the ACC and the ventrolateral prefrontal cortex, insula, precuneus, superior parietal lobule, middle occipital gyrus, inferior temporal gyrus, and lingual gyrus compared with the high-DHA group (P < 0.05; corrected). The low-DHA group did not exhibit greater ACC functional connectivity with any region compared with the high-DHA group. On the CPT-IP task, the low-DHA group had slower reaction time (P = 0.03) which was inversely correlated with erythrocyte DHA among all subjects. DISCUSSION: These data suggest that low-DHA biostatus is associated with reduced event-related functional connectivity in cortical attention networks of typically developing children.

fMRI brain activation changes following treatment of a first bipolar manic episode.

OBJECTIVES: We tested the hypothesis that, with treatment, functional magnetic resonance imaging (fMRI) regional brain activation in first-episode mania would normalize - i.e., that differences from healthy subjects would diminish over time, and would be associated with clinical remission status, potentially identifying neuroanatomic treatment response markers. METHODS: Forty-two participants with bipolar I disorder were recruited during their first manic episode, pseudo-randomized to open-label lithium or quetiapine, and followed for 8 weeks. fMRI scans were obtained at baseline and then after 1 and 8 weeks of treatment, while participants performed a continuous performance task with emotional distracters. Healthy participants received fMRI scans at these same intervals. Specific region-of-interest (ROI) activations within prefrontal emotional networks were assessed as potential measures of treatment response. RESULTS: ROI data were reduced using exploratory factor analysis, which identified five factors that were organizationally consistent with functional anatomic models of human emotion modulation. Half of the participants with bipolar disorder achieved remission by Week 8 and were contrasted with the other half that did not. Analyses demonstrated that, in the bipolar disorder group in general, treatment led to decreases in activation across brain regions toward healthy subject values. However, differences in activation changes were observed between subjects with bipolar disorder who did or did not achieve remission in subcortical and amygdala factors. CONCLUSIONS: These findings provide evidence for potential neuroanatomic treatment response markers in first-episode bipolar disorder.

Effects of fish oil supplementation on prefrontal metabolite concentrations in adolescents with major depressive disorder: a preliminary 1H MRS study.

OBJECTIVE: To use proton magnetic resonance spectroscopy ((1)H MRS) to investigate the effects of fish oil (FO) supplementation on cortical metabolite concentrations in adolescents with major depressive disorder (MDD). METHODS: Metabolite concentrations were determined by (1)H MRS in the anterior cingulate cortex and bilateral dorsolateral prefrontal cortex (DLPFC) of adolescents with MDD before and following 10-week open-label supplementation with low (2.4 g/day, n = 7) or high (16.2 g/day, n = 7) dose FO. Depressive symptom severity scores and erythrocyte fatty acid levels were also determined. RESULTS: Baseline erythrocyte eicosapentaenoic acid (EPA) composition was positively correlated, and arachidonic acid (AA) and the AA/EPA ratio were inversely correlated, with choline (Cho) concentrations in the right DLPFC. Docosahexaenoic acid (DHA) composition was inversely correlated with myo-inositol (mI) concentrations in the left DLPFC. Erythrocyte EPA and DHA composition increased, and AA decreased, significantly following low-dose and high-dose FO supplementation. In the intent-to-treat sample, depressive symptom severity scores decreased significantly in the high-dose group (-40%, P < 0.0001) and there was a trend in the low-dose group (-20%, P = 0.06). There were no significant baseline-endpoint changes in metabolite levels in each voxel. In the low-dose group there were changes with large effect sizes, including a decrease in mI in the left DLPFC (-12%, P = 0.18, d = 0.8) and increases in glutamate + glutamine (Glx) (+12%, P = 0.19, d = 0.8) and Cho (+15%, P = 0.08, d = 1.2) in the right DLPFC. In the high-dose group, there was a trend for increases in Cho in the right DLPFC (+10%, P = 0.09, d = 1.2). DISCUSSION: These preliminary data suggest that increasing the LCn-3 fatty acid status of adolescent MDD patients is associated with subtle changes in Glx, mI, and Cho concentrations in the DLPFC that warrant further evaluation in a larger controlled trial.

Neurofunctional effects of quetiapine in patients with bipolar mania.

OBJECTIVES: Several lines of evidence suggest that abnormalities within portions of the extended limbic network involved in affective regulation and expression contribute to the neuropathophysiology of bipolar disorder. In particular, portions of the prefrontal cortex have been implicated in the appearance of manic symptomatology. The effect of atypical antipsychotics on activation of these regions, however, remains poorly understood. METHODS: Twenty-two patients diagnosed with bipolar mania and 26 healthy subjects participated in a baseline functional magnetic resonance imaging scan during which they performed a continuous performance task with neutral and emotional distractors. Nineteen patients with bipolar disorder were treated for eight weeks with quetiapine monotherapy and then rescanned. Regional activity in response to emotional stimuli was compared between healthy and manic subjects at baseline; and in the subjects with bipolar disorder between baseline and eight-week scans. RESULTS: At baseline, functional activity did not differ between subjects with bipolar disorder and healthy subjects in any region examined. After eight weeks of treatment, subjects with bipolar disorder showed a significant decrease in ratings on the Young Mania Rating Scale (YMRS) (p < 0.001), and increased activation in the right orbitofrontal cortex (OFC) (p = 0.002); there was a significant association between increased right OFC activity and YMRS improvement (p = 0.003). CONCLUSIONS: These findings are consistent with suggestions that mania involves a loss of emotional modulatory activity in the prefrontal cortex--restoration of the relatively greater elevation in prefrontal activity widely observed in euthymic patients is associated with clinical improvement. It is not clear, however, whether changes are related to quetiapine treatment or represent a non-specific marker of affective change.

N-acetyl aspartate levels in adolescents with bipolar and/or cannabis use disorders.

OBJECTIVE: Bipolar and cannabis use disorders commonly co-occur during adolescence, and neurochemical studies may help clarify the pathophysiology underlying this co-occurrence. This study compared metabolite concentrations in the left ventral lateral prefrontal cortex among adolescents with bipolar disorder (bipolar group; n = 14), adolescents with a cannabis use disorder (cannabis use group; n = 13), adolescents with cannabis use and bipolar disorders (bipolar and cannabis group; n = 25), and healthy adolescents (healthy controls; n = 15). We hypothesized that adolescents with bipolar disorder (with or without cannabis use disorder) would have decreased N-acetyl aspartate levels in the ventral lateral prefrontal cortex compared to the other groups and that the bipolar and cannabis group would have the lowest N-acetyl aspartate levels of all groups. METHODS: N-acetyl aspartate concentrations in the left ventral lateral prefrontal cortex were obtained using proton magnetic resonance spectroscopy. RESULTS: Adolescents with bipolar disorder showed significantly lower left ventral lateral prefrontal cortex N-acetyl aspartate levels, but post hoc analyses indicated that this was primarily due to increased N-acetyl aspartate levels in the cannabis group. The cannabis use disorder group had significantly higher N-acetyl aspartate levels compared to the bipolar disorder and the bipolar and cannabis groups (p = .0002 and p = .0002, respectively). Pearson correlations revealed a significant positive correlation between amount of cannabis used and N-acetyl aspartate concentrations. CONCLUSIONS: Adolescents with cannabis use disorder showed higher levels of N-acetyl aspartate concentrations that were significantly positively associated with the amount of cannabis used; however, this finding was not present in adolescents with comorbid bipolar disorder.

Neurochemical effects of quetiapine in patients with bipolar mania: a proton magnetic resonance spectroscopy study.

Although the neurophysiology underlying pharmacotherapy for bipolar disorder remains poorly understood, recent studies suggest that therapeutic mechanisms may be reflected in changes in concentrations of N-acetylaspartate (NAA), a putative measure of neuronal integrity and metabolism. In this study, we used magnetic resonance spectroscopy (MRS) to examine prefrontal NAA in patients receiving quetiapine for bipolar mania. On the basis of previous findings, we hypothesized that remission would be associated with increased NAA concentrations in the prefrontal cortex. Thirty-one manic bipolar patients and 13 healthy subjects were recruited to participate in this prospective study. All subjects participated in MRS at baseline and after 8 weeks of treatment. Bipolar subjects received open-label quetiapine monotherapy (mean dose [SD], 584 [191] mg). Fourteen patients remitted (Young Mania Rating Scale ≤ 12) ("remitters"), 11 patients did not ("nonremitters"), and 6 patients were lost to follow-up. Bipolar and healthy subjects did not significantly differ in baseline NAA or degree of change during the 8 weeks. Remitters showed greater mean baseline NAA concentrations in the right ventrolateral prefrontal cortex compared with nonremitters (P < 0.05). In the anterior cingulate, remitters showed near significantly decreased baseline NAA concentrations at baseline (P < 0.06), and significant differences in NAA change during the 8 weeks of treatment (P < 0.03). Manic patients who remitted with quetiapine treatment in the course of this study exhibited distinct patterns of baseline prefrontal NAA concentration, coupled with decreased NAA in the anterior cingulate with treatment; the latter possibly reflecting disparate effects of quetiapine on neuronal metabolism. These data support suggestions that therapeutic effects of quetiapine involve metabolic effects on specific prefrontal regions.

A pilot study of anterior cingulate cortex neurochemistry in adolescents with generalized anxiety disorder.

BACKGROUND/AIMS: This study used proton magnetic resonance spectroscopy (¹H MRS) to evaluate the neurochemistry of the anterior cingulate cortex (ACC) in adolescents with generalized anxiety disorder (GAD). METHODS: Adolescents with GAD (n = 10) and healthy subjects (n = 10) underwent a ¹H MRS scan at 4 T. Glutamate (Glu), N-acetyl aspartate, creatine (Cr) and myo-inositol concentrations were measured in the ACC and were compared between untreated adolescents with GAD and age- and sex-matched healthy subjects. RESULTS: Glu/Cr ratios in the ACC correlated with the severity of both generalized anxiety symptoms on the Pediatric Anxiety Rating Scale and with total anxiety symptom severity as measured by the Hamilton Anxiety Rating Scale, but did not differ between adolescents with GAD and healthy subjects. In addition, no differences in N-acetyl aspartate, Cr, or myo-inositol were detected between groups. CONCLUSION: These findings suggest that Glu/Cr in untreated adolescents with GAD may relate to the severity of anxiety symptoms and raise the possibility that dysregulation of Glu within the ACC may be linked to the pathophysiology of pediatric GAD.

Low docosahexaenoic acid status is associated with reduced indices in cortical integrity in the anterior cingulate of healthy male children: a 1H MRS Study.

Docosahexaenoic acid (DHA, 22:6n-3) is the principal omega-3 fatty acid in mammalian brain gray matter, and emerging preclinical evidence suggests that DHA has neurotrophic and neuroprotective properties. This study investigated relationships among DHA status, neurocognitive performance, and cortical metabolism measured with proton magnetic resonance spectroscopy (1H MRS) in healthy developing male children (aged 8-10 years, n = 38). Subjects were segregated into low-DHA (n = 19) and high-DHA (n = 19) status groups by a median split of erythrocyte DHA levels. Group differences in 1H MRS indices of cortical metabolism, including choline (Cho), creatine (Cr), glutamine + glutamate + γ-aminobutyric acid (Glx), myo-inositol (mI), and n-acetyl aspartate (NAA), were determined in the right and left dorsolateral prefrontal cortex (R/L-DLPFC, BA9) and bilateral anterior cingulate cortex (ACC, BA32/33). Group differences in neurocognitive performance were evaluated with the Kaufman Brief Intelligence Test and identical-pairs version of the continuous performance task (CPT-IP). Subjects in the low-DHA group consumed fish less frequently (P = 0.02), had slower reaction times on the CPT-IP (P = 0.007), and exhibited lower mI (P = 0.007), NAA (P = 0.007), Cho (P = 0.009), and Cr (P = 0.01) concentrations in the ACC compared with the high-DHA group. There were no group differences in ACC Glx or any metabolite in the L-DLPFC and R-DLPFC. These data indicate that low-DHA status is associated with reduced indices of metabolic function in the ACC and slower reaction time during sustained attention in developing male children.

Establishing a training plan and estimating inter-rater reliability across the multi-site Texas childhood trauma research network.

OBJECTIVE: Minimal guidance is available in the literature to develop protocols for training non-clinician raters to administer semi-structured psychiatric interviews in large, multi-site studies. Previous work has not produced standardized methods for maintaining rater quality control or estimating interrater reliability (IRR) in such studies. Our objective is to describe the multi-site Texas Childhood Trauma Research Network (TX-CTRN) rater training protocol and activities used to maintain rater calibration and evaluate protocol effectiveness. METHODS: Rater training utilized synchronous and asynchronous didactic learning modules, and certification involved critique of videotaped mock scale administration. Certified raters attended monthly review meetings and completed ongoing scoring exercises for quality assurance purposes. Training protocol effectiveness was evaluated using individual measure and pooled estimated IRRs for three key study measures (TESI-C, CAPS-CA-5, MINI-KID [Major Depressive Episodes - MDE & Posttraumatic Stress Disorder - PTSD modules]). A random selection of video-recorded administrations of these measures was evaluated by three certified raters to estimate agreement statistics, with jackknife (on the videos) used for confidence interval estimation. Kappa, weighted kappa and intraclass correlations were calculated for study measure ratings. RESULTS: IRR agreement across all measures was strong (TESI-C median kappa 0.79, lower 95% CB 0.66; CAPS-CA-5 median weighted kappa 0.71 (0.62), MINI-MDE median kappa 0.71 (0.62), MINI-PTSD median kappa 0.91 (0.9). The combined estimated ICC was ≥0.86 (lower CBs ≥0.69). CONCLUSIONS: The protocol developed by TX-CTRN may serve as a model for other multi-site studies that require comprehensive non-clinician rater training, quality assurance guidelines, and a system for assessing and estimating IRR.

Brain functional activation and first mood episode in youth at risk for bipolar disorder.

BACKGROUND: In order to identify biomarkers of prodromal mood disorders, we examined functional brain activation in children and adolescent at familial risk for bipolar disorder. METHODS: Offspring of parents with bipolar I disorder (at-risk youth; N = 115, mean ± SD age: 13.6 ± 2.7; 54 % girls) and group-matched offspring of healthy parents (healthy controls; N = 58, mean ± SD age: 14.2 ± 3.0; 53 % girls) underwent functional magnetic resonance imaging while performing a continuous performance task with emotional and neutral distracters. At baseline, at-risk youth had no history of mood episodes or psychotic disorders. Subjects were followed longitudinally until developing their first mood episode or being lost to follow-up. Standard event-related region-of-interest (ROI) analyses were performed to compare brain activation at baseline between groups and in survival analyses. RESULTS: At baseline, at-risk youth exhibited reduced activation to emotional distracters in the right ventrolateral prefrontal cortex (VLPFC) (p = 0.04). Activation was not significantly altered in additional ROIs, including left VLPFC, bilateral amygdala, caudate, or putamen. In those at-risk youth who developed their first mood episode during follow-up (n = 17), baseline increased activation in right VLPFC, right caudate, and right putamen activation predicted the development of a mood episode. LIMITATIONS: Sample size of converters, loss to follow-up, and number of statistical comparisons. CONCLUSIONS: We found preliminary evidence that a reduced activation in right VLPFC might be a marker of risk for or resilience to mood disorders in at-risk youth. Conversely, an increased activation in the right VLPFC, caudate, and putamen might indicate an increased risk for the later development of their first mood episode.

Neurocircuitry of generalized anxiety disorder in adolescents: a pilot functional neuroimaging and functional connectivity study.

BACKGROUND: Dysfunction of neural systems responsible for the processing of emotional stimuli is hypothesized to be involved in the pathophysiology of generalized anxiety disorder (GAD) in adolescents. We used standard fMRI and functional connectivity analyses to examine the functional neurocircuitry of GAD in adolescents. METHODS: Ten adolescents with GAD and 10 healthy comparison subjects underwent fMRI while performing a continuous performance task with emotional and neutral distractors. Standard event-related voxel-wise fMRI and steady-state functional connectivity analyses were performed. RESULTS: Increased activation was observed in the left medial prefrontal cortex and right ventrolateral prefrontal cortex (VLPFC) in response to emotional images compared to neutral imagines in youth with GAD. Connectivity analyses using the right VLPFC seed region suggested decreased connectivity between this region and the bilateral medial prefrontal cortex. Connectivity analyses using the right amygdala seed region revealed decreased correlation with the posterior cingulate cortex in adolescents with GAD. The left amygdala seed region demonstrated increased connectivity with the ipsilateral precuneus in youth with GAD compared to healthy subjects. CONCLUSIONS: In addition to increased activation of the medial prefrontal cortex and right VLPFC, we observed altered connectivity between the amygdala or VLPFC and regions, which subserve mentalization (e.g. posterior cingulate cortex, precuneus, and medial prefrontal cortex). This suggests that structures that regulate emotion and affect interact abnormally with key structures that are involved in mentalization, a process known to be disrupted in GAD.

Progressive neurostructural changes in adolescent and adult patients with bipolar disorder.

OBJECTIVES: Several lines of evidence suggest that bipolar disorder is associated with progressive changes in gray matter volume (GMV), particularly in brain structures involved in emotional regulation and expression. The majority of these studies however, have been cross-sectional in nature. In this study we compared baseline and follow-up scans in groups of bipolar disorder and healthy subjects. We hypothesized bipolar disorder subjects would demonstrate significant GMV changes over time. METHODS: A total of 58 bipolar disorder and 48 healthy subjects participated in structural magnetic resonance imaging (MRI). Subjects were rescanned 3-34 months after their baseline MRI. MRI images were segmented, normalized to standard stereotactic space, and compared voxel-by-voxel using statistical parametrical mapping software (SPM2). A model was developed to investigate differences in GMV at baseline, and associated with time and episodes, as well as in comparison to healthy subjects. RESULTS: We observed increases in GMV in bipolar disorder subjects across several brain regions at baseline and over time, including portions of the prefrontal cortex as well as limbic and subcortical structures. Time-related changes differed to some degree between adolescent and adult bipolar disorder subjects. The interval between scans positively correlated with GMV increases in bipolar disorder subjects in portions of the prefrontal cortex, and both illness duration and number of depressive episodes were associated with increased GMV in subcortical and limbic structures. CONCLUSIONS: Our findings support suggestions that widely observed progressive neurofunctional changes in bipolar disorder patients may be related to structural brain abnormalities in anterior limbic structures. Abnormalities largely involve regions previously noted to be integral to emotional expression and regulation, and appear to vary by age.

Recent Perceived Stress, Amygdala Reactivity to Acute Psychosocial Stress, and Alcohol and Cannabis Use in Adolescents and Young Adults With Bipolar Disorder.

Background: Psychosocial stress negatively affects the clinical course of bipolar disorder. Studies primarily focused on adults with bipolar disorder suggest the impact of stress is progressive, i.e., stress response sensitizes with age. Neural mechanisms underlying stress sensitization are unknown. As stress-related mechanisms contribute to alcohol/substance use disorders, variation in stress response in youth with bipolar disorder may contribute to development of co-occurring alcohol/substance use disorders. This study investigated relations between psychosocial stress, amygdala reactivity, and alcohol and cannabis use in youth with bipolar disorder, compared to typically developing youth. Methods: Forty-two adolescents/young adults [19 with bipolar disorder, 23 typically developing, 71% female, agemean ± SD = 21 ± 2 years] completed the Perceived Stress Scale (PSS), Daily Drinking Questionnaire modified for heaviest drinking week, and a modified Montreal Imaging Stress functional MRI Task. Amygdala activation was measured for both the control and stress conditions. Main effects of group, condition, total PSS, and their interactions on amygdala activation were modeled. Relationships between amygdala response to acute stress with recent alcohol/cannabis use were investigated. Results: Greater perceived stress related to increased right amygdala activation in response to the stress, compared to control, condition in bipolar disorder, but not in typically developing youth (group × condition × PSS interaction, p = 0.02). Greater amygdala reactivity to acute stress correlated with greater quantity and frequency of alcohol use and frequency of cannabis use in bipolar disorder. Conclusion: Recent perceived stress is associated with changes in amygdala activation during acute stress with amygdala reactivity related to alcohol/cannabis use in youth with bipolar disorder.

Childhood maltreatment, prefrontal-paralimbic gray matter volume, and substance use in young adults and interactions with risk for bipolar disorder.

Childhood maltreatment is associated with adverse effects on the brain, and an increased risk for psychopathology, including mood and substance use disorders. Individuals vary on the degree to which they exhibit neurobiological and clinical differences following maltreatment. Individuals with bipolar disorder exhibit greater magnitude of maltreatment-related prefrontal-paralimbic gray matter volume (GMV) deficits compared to typically developing individuals. It is unclear if greater structural differences stem from greater neural vulnerability to maltreatment in bipolar disorder, or if they relate to presence of other clinical features associated with childhood maltreatment, e.g., elevated prevalence of comorbid substance use disorders. To investigate this, we compared young adults with a family history of bipolar disorder (n = 21), but who did not fulfill diagnostic criteria for bipolar disorder, with typically developing young adults without a family history of bipolar disorder (n = 26). Participants completed structural neuroimaging, clinical and family history interviews, and assessment of childhood maltreatment and recent alcohol and cannabis use patterns. We examined relations between childhood maltreatment and prefrontal-paralimbic GMV by modeling main effects of maltreatment and family history group by maltreatment interactions on prefrontal-paralimbic GMV. We also examined relations between maltreatment and associated GMV changes with recent alcohol and cannabis use. Childhood maltreatment correlated with lower ventral, rostral and dorsolateral prefrontal and insular cortical GMV across all participants regardless of the presence or absence of familial history of bipolar disorder. However, exploratory analyses did reveal greater maltreatment-related GMV differences in individuals with prodromal symptoms of depression. Lower insula GMV was associated with greater frequency of cannabis use across all participants and greater quantity of alcohol use only in those with familial risk for bipolar disorder. Results suggest familial risk for bipolar disorder, and presumably genetic risk, may relate to outcomes following childhood maltreatment and should be considered in prevention/early intervention strategies.

Subjective response to alcohol: Associated alcohol use and orbitofrontal gray matter volume in bipolar disorder.

BACKGROUND: Alcohol use disorders (AUDs) are highly prevalent in bipolar disorder, however the developmental etiology of this comorbidity remains unknown. Structural differences in the orbitofrontal cortex (OFC) have been linked to problematic drinking in bipolar disorder and typically developing youth, with evidence implicating variations in OFC in differential subjective response to alcohol in typical development. METHODS: Subjective response to alcohol, recent alcohol use, impulsivity, and variation in OFC gray matter volume were investigated in 48 emerging adults (24 with bipolar disorder, 24 typically developing). On average 1.5 years later, drinking patterns were reassessed and relations between subjective response and changes in alcohol use were explored. RESULTS: Groups did not differ in baseline alcohol use or subjective response. At baseline, decreased subjective response to alcohol was associated with increased alcohol use in both groups. Lower gray matter volume in medial OFC in bipolar disorder was associated with increased subjective response to alcohol, whereas lower gray matter volume in OFC in typically developing participants was associated with decreased subjective response to alcohol. Increase in alcohol use (baseline to follow-up) was associated with increased baseline subjective response to alcohol in bipolar disorder, and decreased baseline subjective response in the typically developing group. LIMITATIONS: Preliminary study with a small sample size. CONCLUSION: Underlying OFC biology may contribute to differences in alcohol sensitivity in bipolar disorder which may also relate to prospective changes in alcohol use patterns. Future studies are needed to examine how these factors prospectively relate to development of AUDs in bipolar disorder.