Neurofunctional effects of quetiapine in patients with bipolar mania

Effects of short-term quetiapine and lithium therapy for acute manic or mixed episodes on the limbic system and emotion regulation circuitry in youth with bipolar disorder

Disruptions in the limbic system, and in emotion regulation circuitry that supports affect modulation, have been reported during acute manic episodes of bipolar disorder (BD). The impact of pharmacological treatment on these deficits, especially in youth, remains poorly characterized. 107 youths with acute manic or mixed episodes of bipolar I disorder and 60 group-matched healthy controls were recruited. Youth with bipolar disorder were randomized to double-blind treatment with quetiapine or lithium and assessed weekly. Task-based fMRI studies were performed using an identical pairs continuous performance task (CPT-IP) at pre-treatment baseline and post-treatment weeks one and six. Region of interest analyses focused on the limbic system and ventral PFC - basal ganglia - thalamocortical loop structures known to be involved in emotion regulation. Changes in regional activation were compared between the two treatment groups, and pretreatment regional activation was used to predict treatment outcome. Mania treatment scores improved more rapidly in the quetiapine than lithium treated group, as did significant normalization of neural activation toward that of healthy individuals in left amygdala (p = 0.007), right putamen (p < 0.001), and right globus pallidus (p = 0.003). Activation changes in the right putamen were correlated with reduction of mania symptoms. The limbic and emotion regulation system activation at baseline and week one predicted treatment outcome in youth with bipolar disorder with significant accuracy (up to 87.5%). Our findings document more rapid functional brain changes associated with quetiapine than lithium treatment in youth with bipolar disorder, with most notable changes in the limbic system and emotion regulation circuitry. Pretreatment alterations in these regions predicted treatment response. These findings advance understanding of regional brain alterations in youth with bipolar disorder, and show that fMRI data can predict treatment outcome before it can be determined clinically, highlighting the potential utility of fMRI biomarkers for early prediction of treatment outcomes in bipolar disorder.Clinical Trials Registration: Name: Multimodal Neuroimaging of Treatment Effects in Adolescent Mania. URL: https://clinicaltrials.gov/ . Registration number: NCT00893581.

Changes in the structural brain connectome over the course of a nonrandomized clinical trial for acute mania

Disrupted topological organization of brain functional networks has been widely reported in bipolar disorder. However, the potential clinical implications of structural connectome abnormalities have not been systematically investigated. The present study included 109 unmedicated subjects with acute mania who were assigned to 8 weeks of treatment with quetiapine or lithium and 60 healthy controls. High resolution 3D-T1 weighted magnetic resonance images (MRI) were collected from both groups at baseline, week 1 and week 8. Brain networks were constructed based on the similarity of morphological features across brain regions and analyzed using graph theory approaches. At baseline, individuals with bipolar disorder illness showed significantly lower clustering coefficient (Cp) (p = 0.012) and normalized characteristic path length (λ) (p = 0.004) compared to healthy individuals, as well as differences in nodal centralities across multiple brain regions. No baseline or post-treatment differences were identified between drug treatment conditions, so change after treatment were considered in the combined treatment groups. Relative to healthy individuals, differences in Cp, λ and cingulate gyrus nodal centrality were significantly reduced with treatment; changes in these parameters correlated with changes in Young Mania Rating Scale scores. Baseline structural connectome matrices significantly differentiated responder and non-responder groups at 8 weeks with 74% accuracy. Global and nodal network alterations evident at baseline were normalized with treatment and these changes associated with symptomatic improvement. Further, baseline structural connectome matrices predicted treatment response. These findings suggest that structural connectome abnormalities are clinically significant and may be useful for predicting clinical outcome of treatment and tracking drug effects on brain anatomy in bipolar disorder.

CLINICAL TRIALS REGISTRATION

Name: Functional and Neurochemical Brain Changes in First-episode Bipolar Mania Following Successful Treatment with Lithium or Quetiapine. URL: https://clinicaltrials.gov/ .

REGISTRATION NUMBER

NCT00609193. Name: Neurofunctional and Neurochemical Markers of Treatment Response in Bipolar Disorder. URL: https://clinicaltrials.gov/ .

REGISTRATION NUMBER

NCT00608075.

Neurofunctional Correlates of Response to Quetiapine in Adolescents with Bipolar Depression

OBJECTIVES

Prior studies have shown that youth with bipolar disorder demonstrate neurofunctional changes in key prefrontal and subcortical brain regions implicated in emotional regulation following treatment with pharmacological agents. We recently reported a large response rate (>60%) to quetiapine (QUET) for treating depressive symptoms in adolescents with bipolar depression. This study investigates the neurofunctional effects of QUET using functional magnetic resonance imaging (fMRI).

METHODS

Thirty-three unmedicated subjects, 10-17 years of age, with a current depressive episode (Children's Depression Rating Scale-Revised [CDRS-R] > 40) associated with bipolar I or II disorder were recruited in a two-site randomized, placebo (PBO)-controlled trial of QUET monotherapy for treatment of bipolar depression in adolescents. Twenty-three of these participants (nine male) underwent an MRI scan at baseline, then were randomized to QUET or PBO, followed for 8 weeks, and at the end of their study participation underwent another MRI scan. During the fMRI scan, subjects viewed negative and neutral pictures and rated the valence of each picture.

RESULTS

Sixteen subjects had usable data at both time points: 10 subjects randomized to QUET, and 6 randomized to PBO. For QUET subjects, lower baseline activation in the left dorsolateral prefrontal cortex (p < 0.005) and higher baseline activation in the left ventrolateral prefrontal cortex (p = 0.0024) predicted greater improvement in CDRS-R scores from baseline to follow-up. When QUET and PBO groups were combined (n = 16), region-of-interest activation did not significantly predict change in CDRS-R.

CONCLUSIONS

Baseline activation patterns in dorsal and ventral portions of the prefrontal cortex that are critical for the regulation of emotion-predicted response, but only within the QUET group. Thus, specific medications may be more effective in the context of specific prefrontal activation patterns in youth with bipolar depression. Larger studies of these youth would help to clarify the effects of QUET on brain activation.

A Brain on a Roller Coaster: Can the Dopamine Reward System Act as a Protagonist to Subdue the Ups and Downs of Bipolar Disorder?

One of the most interesting but tenebrous parts of the bipolar disorder (BD) story is the switch between (hypo)mania and depression, which can give bipolar patients a thrilling, but somewhat perilous, ‘ride’. Numerous studies have pointed out that there are some recognizable differences (either state-dependent or state-independent) in several brain regions of people with BD, including components of the brain’s reward system. Understanding the underpinning mechanisms of high and low mood statuses in BD has potential, not only for the development of highly specific and selective pharmaceutical agents, but also for better treatment approaches and psychological interventions to manage BD and, thus, give patients a safer ride. Herein, we review evidence that supports involvement of the reward system in the pathophysiology of mood swings, with the main focus on the mesocorticolimbic dopaminergic neural circuitry. Principally using findings from neuroimaging studies, we aim to signpost readers as to how mood alterations may affect different areas of the reward system and how antipsychotic drugs can influence the activity of these brain areas. Finally, we critically evaluate the hypothesis that the mesocorticolimbic dopamine reward system may act as a functional rheostat for different mood states.

Brain functional effects of psychopharmacological treatments in bipolar disorder

Functional magnetic resonance imaging (fMRI) studies have contributed to the understanding of bipolar disorder. However the effect of medication on brain activation remains poorly understood. We conducted an extensive literature review on PubMed and ScienceDirect to investigate the influence of medication in fMRI studies, including both longitudinal and cross-sectional studies, which aimed at assessing this influence. Although we reported all reviewed studies, we gave greater emphasis to studies with the most robust methodology. One hundred and forty studies matched our inclusion criteria and forty-seven studies demonstrated an effect of pharmacological treatment on fMRI blood oxygen level dependent (BOLD) signal in adults and children with bipolar disorder. Out of these studies, nineteen were longitudinal. Most of cross-sectional studies suffered from methodological bias, due to post-hoc analyses performed on a limited number of patients and did not find any effect of medication. However, both longitudinal and cross-sectional studies showing an impact of treatment tend to suggest that medication prescribed to patients with bipolar disorder mostly influenced brain activation in prefrontal regions, when measured by tasks involving emotional regulation and processing as well as non-emotional cognitive tasks. FMRI promises to elucidate potential new biomarkers in bipolar disorder and could be used to evaluate the effect of new therapeutic compounds. Further research is needed to disentangle the effect of medication and the influence of the changes in mood state on brain activation in patients with bipolar disorder.

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.