Relationship between regional brain metabolism, illness severity and age in depressed subjects

Treatment of Refractory Bipolar Depression With Stereotactic Radiosurgery Targeting the Subgenual Cingulate Cortex

Background The subgenual cingulate cortex (SGC) has been identified as a key structure within multiple neural circuits whose dysfunction is implicated in the neurobiology of depression. Deep brain stimulation in the SGC is thought to reduce and normalize local metabolism, causing normalization of circuit behavior and an improvement in depressive symptoms. We hypothesized that nonablative stereotactic radiosurgery (SRS) to the SGC would reduce local metabolism and reduce the severity of depression in patients with treatment-resistant bipolar depression. Methods Under the FDA's Humanitarian Device Exemption program, patients were screened for inclusion and exclusion criteria. Three volunteers meeting the criteria provided informed consent. Bilateral SGC targets were irradiated to a maximum dose of 75 Gy in one fraction. Subjects were followed for one year following the procedure with mood assessments (Hamilton Depression Rating Scale (HDRS), Clinical Global Impression-Improvement, Clinical Global Impression-Severity, and Young Mania Rating Scale), neurocognitive testing (Delis-Kaplan Executive Function System, Wechsler Adult Intelligence Scale III digit span, and California Verbal Learning Test II), and imaging. Further imaging was completed approximately two years after the procedure. Clinical improvement was defined as a ≥50% reduction in HDRS. Results Two of the three subjects showed clinical improvement in depressive symptoms during the follow-up period, while one subject showed no change in symptom severity. One of three subjects was hospitalized for the emergence of an episode of psychotic mania after discontinuing antipsychotic medications against medical advice but promptly recovered with the reinstitution of an antipsychotic. Sequential assessments did not reveal impairment in any cognitive domain assessed. For one of the three subjects, MRI imaging showed evidence of edema at 12 months post-SRS, which resolved at 22 months post-procedure. In a second of three patients, there was evidence of local edema at the target site at long-term follow-up. All imaging changes were asymptomatic. Conclusion Radiosurgical targeting of the SGC may be a noninvasive strategy for the reduction of severe depression in treatment-resistant bipolar disorder. Two out of three patients showed clinical improvement. While these results are promising, further study, including improvements in target selection and dosing considerations, is needed.

Transcranial Magnetic Stimulation and its Imaging Features in Patients With Depression, Post-traumatic Stress Disorder, and Traumatic Brain Injury

Transcranial magnetic stimulation (TMS) is a type of noninvasive neurostimulation used increasingly often in clinical medicine. While most studies to date have focused on TMS's ability to treat major depressive disorder, it has shown promise in several other conditions including post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI). As different treatment protocols are often used across studies, the ability to predict patient outcomes and evaluate immediate and long-term changes using imaging becomes increasingly important. Several imaging features, such as thickness, connectedness, and baseline activity of a variety of cortical and subcortical areas, have been found to be correlated with a greater response to TMS therapy. Intrastimulation imaging can reveal in real time how TMS applied to superficial areas activates or inhibits activity in deeper brain regions. Functional imaging performed weeks to months after treatment can offer an understanding of how long-term effects on brain activity relate to clinical improvement. Further work should be done to expand our knowledge of imaging features relevant to TMS therapy and how they vary across patients with different neurological and psychiatric conditions.

Lactate in the brain: from metabolic end-product to signalling molecule

Lactate in the brain has long been associated with ischaemia; however, more recent evidence shows that it can be found there under physiological conditions. In the brain, lactate is formed predominantly in astrocytes from glucose or glycogen in response to neuronal activity signals. Thus, neurons and astrocytes show tight metabolic coupling. Lactate is transferred from astrocytes to neurons to match the neuronal energetic needs, and to provide signals that modulate neuronal functions, including excitability, plasticity and memory consolidation. In addition, lactate affects several homeostatic functions. Overall, lactate ensures adequate energy supply, modulates neuronal excitability levels and regulates adaptive functions in order to set the 'homeostatic tone' of the nervous system.

Tobacco Use Decreases Visual Sensitivity in Schizophrenia

Smoking prevalence in patients who are diagnosed with schizophrenia (SCZ) is higher than in the general population. Chronic tobacco use in SCZ patients may reduce the side effects of antipsychotic drugs, thus serving as a self-medication for such side effects. Understanding the ways in which chronic tobacco use influences visual sensitivity has clinical implications, which may serve as a tool for non-invasively diagnosing early-stage visual processing deficits. The present study evaluated the effects of chronic tobacco use on visual sensitivity in SCZ patients. Our purpose was to provide new directions for future research, mainly psychophysical and electrophysiological studies. In the present study, 40 smoker controls (SC), 20 SCZ tobacco users, and 20 SCZ tobacco nonusers were recruited from the Psychosocial Care Center. Visual sensitivity was compared between both SCZ groups and the SC group. Patients with SCZ who were chronic tobacco users presented lower visual sensitivity for chromatic (p < 0.001) and achromatic (p < 0.001) stimuli compared with the other groups. Our findings highlight the need to evaluate possible addictive behavior in patients with SCZ, which may contribute to public policies that seek to improve the quality of life of SCZ patients and their families.

Risk of developing major depressive disorder and anxiety disorders among adolescents and adults with atopic dermatitis: a nationwide longitudinal study

BACKGROUND

Previous cross-sectional studies have suggested a comorbid association between atopic dermatitis (AD) and depressive disorder as well as anxiety disorders, but the temporal relationship was not determined.

METHODS

Using the Taiwan National Health Insurance Research Database, 8208 AD patients aged 12 and older without psychiatric history and age-/sex-matched (1:1) controls between 1998 and 2008 were enrolled in our study and followed to the end of 2011. Subjects who developed major depression, any depressive disorder, and anxiety disorders during the follow-up were identified.

RESULTS

The Cox regression analysis after adjusting for demographic data and atopic comorbidities demonstrated that patients with AD had an elevated risk of developing major depression (hazard ratio [HR]: 6.56, 95% confidence interval [CI]: 3.64-11.84), any depressive disorder (HR: 5.44, 95% CI: 3.99-7.44), and anxiety disorders (HR: 3.57, 95% CI: 2.55-4.98). Stratified by age group, both adolescents and adults with AD were prone to developing major depression (HR: 4.26, 95% CI: 1.39-13.13; HR: 7.56, 95% CI: 3.75-15.23), any depressive disorder (HR: 4.38, 95% CI: 2.09-9.18; HR: 5.66, 95% CI: 4.01-7.99), and anxiety disorders (HR: 5.40, 95% CI: 2.02-14.39; HR: 3.36, 95% CI: 2.38-4.80).

CONCLUSIONS

AD in both adolescence and adulthood increased the risk of developing major depression, any depressive disorder, and anxiety disorders in later life. Further studies would be required to clarify the possible underlying mechanism between AD and depression as well as anxiety disorders.

The neural basis of the abnormal self-referential processing and its impact on cognitive control in depressed patients

Persistent pondering over negative self-related thoughts is a central feature of depressive psychopathology. In this study, we sought to investigate the neural correlates of abnormal negative self-referential processing (SRP) in patients with Major Depressive Disorder and its impact on subsequent cognitive control-related neuronal activation. We hypothesized aberrant activation dynamics during the period of negative and neutral SRP in the rostral anterior cingulate cortex (rACC) and in the amygdala in patients with major depressive disorder. Additionally, we assumed abnormal activation in the fronto-cingulate network during Stroop task execution. 19 depressed patients and 20 healthy controls participated in the study. Using an event-related functional magnetic resonance imaging (fMRI) design, negative, positive and neutral self-referential statements were displayed for 6.5 s and followed by incongruent or congruent Stroop conditions. The data were analyzed with SPM8. In contrast to controls, patients exhibited no significant valence-dependent rACC activation differences during SRP. A novel finding was the significant activation of the amygdala and the reward-processing network during presentation of neutral self-referential stimuli relative to baseline and to affective stimuli in patients. The fMRI analysis of the Stroop task revealed a reduced BOLD activation in the right fronto-parietal network of patients in the incongruent condition after negative SRP only. Thus, the inflexible activation in the rACC may correspond to the inability of depressed patients to shift their attention away from negative self-related stimuli. The accompanying negative affect and task-irrelevant emotional processing may compete for neuronal resources with cognitive control processes and lead thereby to deficient cognitive performance associated with decreased fronto-parietal activation.

Determinants of brain SPECT perfusion and connectivity in treatment-resistant depression

This study aims to characterize and compare functional brain single photon emission tomography (SPECT) perfusion and connectivity in treatment-resistant depression (TRD) according to distinct demographic or clinical profiles (male vs. female; old vs. young; unipolar vs. bipolar) and to study their relationship to the severity and the duration of episode/illness. We retrospectively included 127 consecutive patients who met DSM-IV criteria for a nonpsychotic major TRD episode. All patients were studied using (99m)Tc-ethyl cysteinate dimer SPECT. Whole-brain, voxel-based, between-groups analyses were performed according to demographic and clinical data and in comparison to 37 healthy subjects. Voxel-wise interregional correlation was also performed to compare functional SPECT connectivity. Finally, relationships were searched for regarding severity and duration of episode/illness. The whole group of patients exhibited significant hypoperfusion within bilateral fronto-temporal, insular, and anterior cingulate cortices, as well as within the left caudate. Functional connectivity between left frontal and left cerebellar regions was higher in patients than in healthy subjects. Gender, age, and type of mood disorder did not influence these SPECT patterns. A significant relationship was found between brain SPECT perfusion and either duration or global severity of illness in particular frontal areas. Our data support the hypothesis of a shared SPECT pattern, whatever the profile of TRD, involving fronto-temporal regions and the cerebellum.

Striatal dopamine D2/3 receptor availability in treatment resistant depression

Several studies demonstrated improvement of depressive symptoms in treatment resistant depression (TRD) after administering dopamine agonists which suggest abnormal dopaminergic neurotransmission in TRD. However, the role of dopaminergic signaling through measurement of striatal dopamine D(2/3) receptor (D2/3R) binding has not been investigated in TRD subjects. We used [(123)I]IBZM single photon emission computed tomography (SPECT) to investigate striatal D2/3R binding in TRD. We included 6 severe TRD patients, 11 severe TRD patients on antipsychotics (TRD AP group) and 15 matched healthy controls. Results showed no significant difference (p = 0.75) in striatal D2/3R availability was found between TRD patients and healthy controls. In the TRD AP group D2/3R availability was significantly decreased (reflecting occupancy of D2/3Rs by antipsychotics) relative to TRD patients and healthy controls (p<0.001) but there were no differences in clinical symptoms between TRD AP and TRD patients. This preliminary study therefore does not provide evidence for large differences in D2/3 availability in severe TRD patients and suggests this TRD subgroup is not characterized by altered dopaminergic transmission. Atypical antipsychotics appear to have no clinical benefit in severe TRD patients who remain depressed, despite their strong occupancy of D2/3Rs.

Allergic rhinitis in adolescence increases the risk of depression in later life: a nationwide population-based prospective cohort study

BACKGROUND

Many cross-sectional studies have suggested an association between allergic rhinitis (AR) and depression, but the timing relationship was not determined. Using a nationwide population-based prospective cohort study (1:4, age-/gender-matched), we hypothesized that AR in adolescence would increase the risk of depression in later life.

METHODS

In all, 1673 adolescents aged 12-15 that had AR between 1996 and 2000 were recruited for our study. Cases of major depressive disorder and any depressive disorder that occurred to the end of follow-up (December 31, 2010) were identified.

RESULT

Adolescents with AR had a higher prevalence of major depression (2.5% vs. 1.2%, p<0.001) and any depressive disorder (4.9% vs. 2.8%, p<0.001) and an earlier onset of major depression (19.31 ± 2.91 vs. 20.43 ± 2.71 years, p=0.038) and any depressive disorder (19.35 ± 2.63 vs. 20.43 ± 2.62 years, p=0.002) compared with the controls. The Cox regression model showed that adolescents with AR had increased HRs of major depression (HR: 1.59, 95% CI: 1.02-2.50) and any depressive disorder (HR: 1.42, 95% CI: 1.04-1.93) after controlling residence location and comorbid allergic diseases.

LIMITATIONS

The prevalence of depressive disorder may be underestimated because only those who had medicine-seeking behaviors were enrolled.

CONCLUSIONS

This first cohort case-control study showed an association between AR in early adolescence and depression in late adolescence and early adulthood. Our results suggested that allergic responses played important roles in the development of depression.

Temporal relationships between depressive symptoms and white matter hyperintensities in older men and women

OBJECTIVE

Associations between vascular disease and depression in late life, including increased white matter hyperintensities (WMHs), have been reported. Whether depression is an etiology or a consequence of vascular disease is still unknown. We investigated the temporal relationship between depressive symptoms and WMHs in older men and women.

METHODS

We utilized data from 90 dementia-free older adults (39 women, 51 men), 57 years of age and older at baseline, from the neuroimaging substudy of the Baltimore Longitudinal Study of Aging. Participants were followed for up to 8 years. Ratings of white matter disease burden were available for the first, last, and at least one interim visit, and participants completed the Center for Epidemiologic Studies Depression Scale (CES-D) annually. Statistical models, performed separately in men and women, examined whether depressive symptoms predicted subsequent WMH ratings or WMHs predicted subsequent depressive symptoms.

RESULTS

The total CES-D score was not associated with WMHs in men or women. In men, the CES-D depressed mood subscale predicted accelerating longitudinal increases in WMHs at older ages, but WMHs did not predict subsequent depressive symptoms. In women, there were no significant associations between the CES-D depressed mood subscale and WMHs.

CONCLUSIONS

White matter disease may be a consequence of depressed mood in men but not in women. Intervention strategies for depression may slow the progression of white matter disease in older men. These results add to previous findings documenting sex differences in the correlates of depressive disorders in late life.

The prefrontal cortex influence over subcortical and limbic regions governs antidepressant response by N=H/(M+R)

We review the evidence for relationships between metabolic activity of cortical, subcortical and limbic brain regions in depression and the efficacy of antidepressant agents. The influence of these regions can be described by an algebraic equation, N=H/(M+R), where N represents a homeostatic level of executive function, H represents prefrontal (Brodmann areas 9, 10, 11, 12; 46) and cingulate cortex activity (24, 25; 32), M represents subcortical (hippocampus, parahippocampal gyrus) influences, and R represents limbic (amygdala) influences. This hypothesis is based on depressed prefrontal cortex and enhanced amygdala and hippocampal metabolism in major depressive disorder, and the remission of these changes by most antidepressant interventions. The therapeutic efficacy of antidepressant strategies may depend less on their presumptive molecular mechanisms of action and more on their ability to restore the predominant metabolic and executive functions of the prefrontal cortex, and dampen excessive subcortical and limbic influences.

Baseline brain metabolism in resistant depression and response to transcranial magnetic stimulation

Neuroimaging studies of patients with treatment-resistant depression (TRD) have reported abnormalities in the frontal and temporal regions. We sought to determine whether metabolism in these regions might be related to response to repetitive transcranial magnetic stimulation (TMS) in patients with TRD. Magnetic resonance images and baseline resting-state cerebral glucose uptake index (gluMI) obtained using (18)F-fluorodeoxyglucose positron emission tomography were analyzed in TRD patients who had participated in a double-blind, randomized, sham-controlled trial of prefrontal 10 Hz TMS. Among the patients randomized to active TMS, 17 responders, defined as having 50% depression score decrease, and 14 nonresponders were investigated for prestimulation glucose metabolism and compared with 39 healthy subjects using a voxel-based analysis. In nonresponders relative to responders, gluMI was lower in left lateral orbitofrontal cortex (OFC), and higher in left amygdala and uncinate fasciculus. OFC and amygdala gluMI negatively correlated in nonresponders, positively correlated in responders, and did not correlate in healthy subjects. Relative to healthy subjects, both responders and nonresponders displayed lower gluMI in right dorsolateral prefrontal (DLPFC), right anterior cingulate (ACC), and left ventrolateral prefrontal cortices. Additionally, nonresponders had lower gluMI in left DLPFC, ACC, left and right insula, and higher gluMI in left amygdala and uncus. Hypometabolisms were partly explained by gray matter reductions, whereas hypermetabolisms were unrelated to structural changes. The findings suggest that different patterns of frontal-temporal-limbic abnormalities may distinguish responders and nonresponders to prefrontal magnetic stimulation. Both preserved OFC volume and amygdala metabolism might precondition response to TMS.

The effects of Brief Behavioral Activation Therapy for Depression on cognitive control in affective contexts: An fMRI investigation

BACKGROUND

Unipolar major depressive disorder (MDD) is characterized by impaired cognitive control in affective contexts, but the potential for psychotherapy to affect the neural correlates of these functions has not been evaluated.

METHOD

Twelve adults with and 15 adults without MDD participated in two identical functional magnetic resonance imaging (fMRI) scans that utilized a task requiring cognitive control in both sad and neutral contexts. Between scans, MDD outpatients received Behavioral Activation Therapy for Depression, a psychotherapy modality designed to increase engagement with positive stimuli and reduce avoidance behaviors.

RESULTS

Seventy-five percent of adults with MDD were treatment responders, achieving post-treatment Hamilton Rating Scale for Depression score of six or below. Consistent with predictions, psychotherapy resulted in decreased activation in response to cognitive control stimuli presented within a sad context in prefrontal structures, including the paracingulate gyrus, the right orbital frontal cortex, and the right frontal pole. Furthermore, the magnitude of pretreatment activation in the paracingulate gyrus cluster responsive to psychotherapy predicted the magnitude of depressive symptom change after psychotherapy.

LIMITATIONS

Replication with larger samples is needed, as are follow-up studies that involve placebo control groups, wait-list control groups, and alternative forms of antidepressant intervention.

CONCLUSIONS

Behavioral Activation Therapy for Depression improves depressive symptoms and concomitantly influences brain systems mediating cognitive control in affective contexts.

Neurometabolic correlates of depression and disability in episodic cluster headache

A close association between pain, depression and disability has been shown. However, the neurometabolic correlates of this association have been barely investigated in disease states. Episodic cluster headache is a severe headache syndrome and represents a suitable disease model for the investigation of episodic pain. The aim of this study was to explore the relationship between depression and disability as well as pain scores and brain metabolism in patients with cluster headache during the disease period with repetitive pain attacks, but outside an acute attack. Thirteen patients with cluster headache underwent 2-[fluorine-18]-fluoro-2-deoxy-d-glucose positron emission (FDG-PET) and completed questionnaires on depression and disability as well as a pain visual analogue rating scale (VAS). A positive correlation between the depression scores and glucose metabolism was observed in the insular cortex. A positive correlation between the pain disability scores and brain metabolism was detected in the amygdala. The same applied to the pain visual analogue rating scores. Our data underline the association between severe episodic pain, depression and disability. In addition to this clinical observation, our results stress the importance of the insula and amygdala in pain processing and suffering.

Working-memory fMRI reveals cingulate hyperactivation in euthymic major depression

While cognitive impairments are well documented for the acute episode of major depressive disorder (MDD), less is known about cognitive functioning in the euthymic state. For working memory, dysfunctional activation of lateral prefrontal and cingulate cortex has been reported in the acute episode. This study investigates working-memory function and its neurobiological correlate in euthymic MDD patients, particularly whether dysfunctional activation persists when depressive symptoms improve. We investigated 56 subjects with functional magnetic resonance imaging (fMRI) at 3 Tesla. To challenge working-memory function, a classical verbal n-back task (0-, 1-, and 2-back) was used in 28 well-characterized, euthymic, unipolar MDD patients and 28 healthy control subjects matched according to age, sex, and educational level. Data were analyzed using SPM5. In the absence of significant behavioral differences, we observed comparable overall patterns of brain activation in both groups. As expected, both groups showed stronger activation of the typical working-memory network with increasing memory load. However, significant hyperactivation of the cingulate cortex was observed in euthymic patients, while lateral prefrontal activation was comparable between patients and controls. Working-memory challenge in the euthymic state of MDD revealed a dissociation of lateral prefrontal and cingulate brain function. Cingulate function, which is important for both emotional and cognitive processing and their integration, is still abnormal when mood is restored. This could reflect a different speed of normalization in prefrontal and limbic cortices, persistent systematic changes in neuronal networks after an episode of MDD, or a compensatory mechanism to maintain working-memory performance.

The effects of psychotherapy on neural responses to rewards in major depression

BACKGROUND

Unipolar major depressive disorder (MDD) is characterized by anomalous neurobiological responses to pleasant stimuli, a pattern that may be linked to symptoms of anhedonia. However, the potential for psychotherapy to normalize neurobiological responses to pleasant stimuli has not been evaluated.

METHODS

Twelve adults with and 15 adults without MDD participated in two identical functional magnetic resonance imaging scans that used a Wheel of Fortune task. Between scans, MDD outpatients received Behavioral Activation Therapy for Depression, a psychotherapy modality designed to increase engagement with rewarding stimuli and reduce avoidance behaviors.

RESULTS

Seventy-five percent of adults with MDD were treatment responders, achieving post-treatment Hamilton Rating Scale for Depression score of six or below. Relative to changes in brain function in the matched nondepressed group, psychotherapy resulted in functional changes in structures that mediate responses to rewards, including the paracingulate gyrus during reward selection, the right caudate nucleus (i.e., the dorsal striatum), during reward anticipation, and the paracingulate and orbital frontal gyri during reward feedback. There was no effect of diagnostic status or psychotherapy on in-scanner task-related behavioral responses.

CONCLUSIONS

Behavioral Activation Therapy for Depression, a psychotherapy modality designed to increase engagement with rewarding stimuli and reduce avoidance behaviors, results in improved functioning of unique reward structures during different temporal phases of responses to pleasurable stimuli, including the dorsal striatum during reward anticipation.

Frontal Atrophy and Attention Deficits in Older Adults with a History of Elevated Depressive Symptoms

Studies of older adults with depressive disorders indicate greater cognitive deficits and brain alterations than would be expected for their age. There is some evidence that these findings are present after a single episode of depression, but this work has been cross-sectional in nature. We investigated both cross-sectional and longitudinal associations between a history of elevated depressive symptoms (HDS), frontal lobe volumes, and cognitive performance within the context of normal age-related changes over time in the Baltimore Longitudinal Study of Aging. After controlling for age, HDS was associated with smaller total frontal gray matter volumes and with smaller regional volumes in the cingulate gyrus and orbitofrontal cortex. Men, but not women, with HDS showed deficits in auditory attention span at older ages. Results confirm previous reports that even a single episode of depression is associated with adverse outcomes in older adults but suggest that HDS does not affect longitudinal trajectories of cognitive and brain volume change.

Aging and alexithymia: association with reduced right rostral cingulate volume

OBJECTIVES

Previous studies have linked alexithymia to an inability to process emotions appropriately. Older persons show changes in emotion processing and have higher alexithymia scores. Because the anterior cingulate cortex (ACC) is one of the regions showing earlier decline in late-life, and alexithymia seems to be related to a dysfunction in right hemisphere regions including the ACC subserving affective processes, the present study sought to test the hypothesis that reduced ACC volume accounts for the association between older age and alexithymia.

DESIGN

Correlation analyses between functionally distinct ACC subregions, age and alexithymia features.

SETTING

University of Iowa.

PARTICIPANTS

Twenty-four healthy volunteers aged between 24 and 79 years.

MEASUREMENTS

Psychiatric and neuropsychological assessment and assessment of alexithymia using the 20-item Toronto Alexithymia Scale. High-resolution magnetic resonance imaging, and in-house developed methods for ACC parcellation.

RESULTS

Older age directly correlated with higher overall alexithymia and reduced bilateral rostral and right dorsal ACC gray matter volume. Furthermore, higher alexithymia scores correlated with reduced right rostral ACC volume. This correlation seems to be influenced primarily by Factor 3 of the alexithymia scale measuring diversion of attention to external details in place of internal feelings.

CONCLUSIONS

These results suggest that alexithymia in older age may be a result of structural changes in the right rostral ACC.