Increased left posterior parietal-temporal cortex activation after D-fenfluramine in women with panic disorder

Abnormal functional connectivity of brain regions associated with fear network model in panic disorder

Background: Patients with panic disorder (PD) have an abnormal function in brain regions related to fear network is well recognised. However, the traditional fear network model (FNM) which was based on animals' horrible behaviours has been found that it's not enough to explain the pathological mechanism of PD. This study aims to explore brain regions' abnormalities in the new advanced FNM, and estimate whether it can better explain PD.Methods: Magnetic resonance imaging resting-state scans were acquired in 40 patients with PD (35 drug-naïve and 5 drug-free) and 40 healthy controls (HCs). Twelve brain regions in the advanced FNM were chosen as regions of interest (ROIs) to examine the group difference in the ROIs and whole-brain resting-state functional connectivity (rsFC).Results: We found significantly increased thalamic rsFC with the insula, compared with HCs. And it was significantly correlated with HAMA-somatic score. We also found increased thalamic rsFC with occipital gyrus, temporal gyrus, and frontal gyrus when compared with HCs.Conclusions: Taken together, PD patients exhibit abnormal rsFC alterations within the advanced FNM, especially the increased rsFC within thalamus-insula loop, suggesting that excessive sensitivity to external information plays an important role in PD. The advanced FNM may provide a fuller explanation about PD.

Common and different neural markers in major depression and anxiety disorders: A pilot structural magnetic resonance imaging study

Although anxiety and depression often co-occur and share some clinical features, it is still unclear if they are neurobiologically distinct or similar processes. In this study, we explored common and specific cortical morphology alterations in depression and anxiety disorders. Magnetic Resonance Imaging data were acquired from 13 Major Depressive Disorder (MDD), 11 Generalized Anxiety Disorder (GAD), 11 Panic Disorder (PD) patients and 21 healthy controls (HC). Regional cortical thickness, surface area (SA), volume and gyrification were measured and compared among groups. We found left orbitofrontal thinning in all patient groups, as well as disease-specific alterations. MDD showed volume deficits in left precentral gyrus compared to all groups, volume and area deficits in right fusiform gyrus compared to GAD and HC. GAD showed lower SA than MDD and PD in right superior parietal cortex, higher gyrification than HC in right frontal gyrus. PD showed higher gyrification in left superior parietal cortex when compared to MDD and higher SA in left postcentral gyrus compared to all groups. Our results suggest that clinical phenotypic similarities between major depression and anxiety disorders might rely on common prefrontal alterations. Frontotemporal and parietal abnormalities may represent unique biological signatures of depression and anxiety.

Fear Network Model in Panic Disorder: The Past and the Future

The core concept for pathophysiology in panic disorder (PD) is the fear network model (FNM). The alterations in FNM might be linked with disturbances in the autonomic nervous system (ANS), which is a common phenomenon in PD. The traditional FNM included the frontal and limbic regions, which were dysregulated in the feedback mechanism for cognitive control of frontal lobe over the primitive response of limbic system. The exaggerated responses of limbic system are also associated with dysregulation in the neurotransmitter system. The neuroimaging studies also corresponded to FNM concept. However, more extended areas of FNM have been discovered in recent imaging studies, such as sensory regions of occipital, parietal cortex and temporal cortex and insula. The insula might integrate the filtered sensory information via thalamus from the visuospatial and other sensory modalities related to occipital, parietal and temporal lobes. In this review article, the traditional and advanced FNM would be discussed. I would also focus on the current evidences of insula, temporal, parietal and occipital lobes in the pathophysiology. In addition, the white matter and functional connectome studies would be reviewed to support the concept of advanced FNM. An emerging dysregulation model of fronto-limbic-insula and temporooccipito-parietal areas might be revealed according to the combined results of recent neuroimaging studies. The future delineation of advanced FNM model can be beneficial from more extensive and advanced studies focusing on the additional sensory regions of occipital, parietal and temporal cortex to confirm the role of advanced FNM in the pathophysiology of PD.

Common and disorder-specific neural responses to emotional faces in generalised anxiety, social anxiety and panic disorders

BACKGROUND

Although evidence exists for abnormal brain function across various anxiety disorders, direct comparison of neural function across diagnoses is needed to elicit abnormalities common across disorders and those distinct to a particular diagnosis.

AIMS

To delineate common and distinct abnormalities within generalised anxiety (GAD), panic and social anxiety disorder (SAD) during affective processing.

METHOD

Fifty-nine adults (15 with GAD, 15 with panic disorder, 14 with SAD, and 15 healthy controls) underwent functional magnetic resonance imaging while completing a facial emotion matching task with fearful, angry and happy faces.

RESULTS

Greater differential right amygdala activation to matching fearful v. happy facial expressions related to greater negative affectivity (i.e. trait anxiety) and was heightened across all anxiety disorder groups compared with controls. Collapsing across emotional face types, participants with panic disorder uniquely displayed greater posterior insula activation.

CONCLUSIONS

These preliminary results highlight a common neural basis for clinical anxiety in these diagnoses and also suggest the presence of disorder-specific dysfunction.

Visuospatial and mathematical dysfunction in major depressive disorder and/or panic disorder: A study of parietal functioning

The parietal cortex is critical for several different cognitive functions, including visuospatial processing and mathematical abilities. There is strong evidence indicating parietal dysfunction in depression. However, it is less clear whether anxiety is associated with parietal dysfunction and whether comorbid depression and anxiety are associated with greater impairment. The present study compared participants with major depression (MDD), panic disorder (PD), comorbid MDD/PD and controls on neuropsychological measures of visuospatial processing, Judgement of Line Orientation (JLO), and mathematical abilities, Wide Range Achievement Test (WRAT) Arithmetic. Only comorbid MDD/PD was associated with decreased performance on JLO, whereas all psychopathological groups exhibited comparably decreased performance on WRAT Arithmetic. Furthermore, the results were not accounted for by other comorbid disorders, medication use or psychopathology severity. The present study suggests comorbid depression and anxious arousal are associated with impairment in visuospatial processing and provides novel evidence indicating mathematical deficits across depression and/or anxiety. Implications for understanding parietal dysfunction in internalising psychopathology are discussed.

Cerebral lateralization of pro- and anti-social tendencies

Mounting evidence suggest that the right-hemisphere (RH) has a relative advantage, over the left-hemisphere (LH), in mediating social intelligence - identifying social stimuli, understanding the intentions of other people, awareness of the dynamics in social relationships, and successful handling of social interactions. Furthermore, a review and synthesis of the literature suggest that pro-social attitudes and behaviors are associated with physiological activity in the RH, whereas unsocial and anti-social tendencies are mediated primarily by the LH. This hemispheric asymmetry is rooted in several neurobiological and functional differences between the two hemispheres. (I) Positive social interactions often require inhibiting one's immediate desires and considering the perspectives and needs of others. Given that self-control is mediated by the RH, pro-social emotions and behaviors are, therefore, inherently associated with the RH as it subserves the brain's self-restraint mechanisms. (II) The RH mediates experiences of vulnerability. It registers the relative clumsiness and motor weakness of the left limbs, and it is involved, more than the LH, in processing threats and mediating fear. Emotional states of vulnerability trigger the need for affiliation and sociality, therefore the RH has a greater role in mediating pro-social attitudes and behaviors. (III) The RH mediates a holistic mode of representing the world. Holistic perception emphasizes similarities rather than differences, takes a long-term perspective, is associated with divergent thinking and seeing other points-of-view, and it mediates a personal mode of relating to people. All these features of holistic perception facilitate a more empathetic attitude toward others and pro-social behaviors.

Changes in regional homogeneity of parieto-temporal regions in panic disorder patients who achieved remission with antidepressant treatment

OBJECTIVE

This study was aimed to study the treatment effects of antidepressant for regional homogeneity (ReHo), an indicator of synchronization of brain function, in panic disorder (PD) patients.

METHOD

Twenty-one remitted PD patients with escitalopram treatment and 21 healthy controls all received 3-T magnetic resonance imaging scanning at baseline and sixth week. We utilized REST (Resting State FMRI Data Analysis Toolkit, version 1.4) to calculate regional homogeneity (ReHo) of patients and controls at baseline and sixth week. We compared the ReHo at baseline with the ReHo at sixth week to estimate the treatment effects for the ReHo of remitted patients. Besides, inter-scan effects were evaluated in the control group. The group-related differences between remitted patients and controls were also estimated.

RESULTS

Remitted PD patients had increases in ReHo of right Heschl gyrus (superior temporal lobe) and decreases in ReHo of right angular gyrus (parietal lobe). The improvements in severity of panic symptoms were negatively correlated with the changes of ReHo in right superior parietal lobe. However, remitted patients still had lower ReHo than controls in right Heschl gyrus and left thalamus.

CONCLUSION

The changes in ReHo of temporo-parietal regions might represent treatment-related ReHo changes for remission of PD. The residual alterations in ReHo of temporo-thalamic regions might represent group-related ReHo differences for patients with PD.

The neural basis of optimism and pessimism

Our survival and wellness require a balance between optimism and pessimism. Undue pessimism makes life miserable; however, excessive optimism can lead to dangerously risky behaviors. A review and synthesis of the literature on the neurophysiology subserving these two worldviews suggests that optimism and pessimism are differentially associated with the two cerebral hemispheres. High self-esteem, a cheerful attitude that tends to look at the positive aspects of a given situation, as well as an optimistic belief in a bright future are associated with physiological activity in the left-hemisphere (LH). In contrast, a gloomy viewpoint, an inclination to focus on the negative part and exaggerate its significance, low self-esteem as well as a pessimistic view on what the future holds are interlinked with neurophysiological processes in the right-hemisphere (RH). This hemispheric asymmetry in mediating optimistic and pessimistic outlooks is rooted in several biological and functional differences between the two hemispheres. The RH mediation of a watchful and inhibitive mode weaves a sense of insecurity that generates and supports pessimistic thought patterns. Conversely, the LH mediation of an active mode and the positive feedback it receives through its motor dexterity breed a sense of confidence in one's ability to manage life's challenges, and optimism about the future.

Dipole source analysis of auditory P300 response in depressive and anxiety disorders

This paper is to study auditory event-related potential P300 in patients with anxiety and depressive disorders using dipole source analysis. Auditory P300 using 2-stimulus oddball paradigm was collected from 35 patients with anxiety disorder, 32 patients with depressive disorder, and 30 healthy controls. P300 dipole sources and peak amplitude of dipole activities were analyzed. The source analysis resulted in a 4-dipole configuration, where temporal dipoles displayed greater P300 amplitude than that of frontal dipoles. In addition, a right-greater-than-left hemispheric asymmetry of dipole magnitude was found in patients with anxiety disorder, whereas a left-greater-than-right hemispheric asymmetry of dipole magnitude was observed in depressed patients. Results indicated that the asymmetry was more prominent over the temporal dipole than that of frontal dipoles in patients. Patients with anxiety disorder may increase their efforts to enhance temporal dipole activity to compensate for a deficit in frontal cortex processing, while depressed patients show dominating reduction of right temporal activity. The opposite nature of results observed with hemispheric asymmetry in depressive and anxiety disorders could serve to be valuable information for psychiatric studies.

Temporal and right frontal lobe alterations in panic disorder: a quantitative volumetric and voxel-based morphometric MRI study

BACKGROUND

With regard to current neurobiological theories, the aim of our study was to examine possible alterations of temporal and frontal lobe volume in panic disorder (PD).

METHOD

Seventeen in-patients with PD and a group of healthy control subjects (HC) matched for age and gender were investigated by quantitative volumetric magnetic resonance imaging (MRI). Structures of interest were: the temporal lobe, the amygdala-hippocampus complex (AHC) and the frontal lobe. In addition, a voxel-based morphometry (VBM) analysis implemented in Statistical Parametric Mapping 5 (SPM5) was used for a more detailed assessment of possible volume alterations. Modulated grey matter (GM) images were used to test our a priori hypotheses and to present the volumetric results.

RESULTS

Quantitative volumetric MRI revealed a bilateral reduction in temporal lobe volume in patients with PD compared to HC subjects. The AHC was normal. The right frontal lobe volume was also decreased. Using VBM we detected a significant GM volume reduction in the right middle temporal gyrus [Brodmann area (BA) 21] in patients with PD. In addition, there was a reduction in GM volume in the medial part of the orbitofrontal cortex (BA 11).

CONCLUSIONS

Our results of reduced temporal and frontal lobe volume in PD are in agreement with prior studies. By using a recent VBM approach we were able to assess the abnormalities more precisely. The location of GM volume reduction in the right middle temporal gyrus and medial orbitofrontal cortex lends further support to recent aetiological models of PD.

Depression and the hyperactive right-hemisphere

Depression is associated with an inter-hemispheric imbalance; a hyperactive right-hemisphere (RH) and a relatively hypoactive left-hemisphere (LH). Nevertheless, the underlying mechanisms which can explain why depression is associated with a RH dominance remain elusive. This article points out the potential links between functional cerebral asymmetries and specific symptoms and features of depression. There is evidence that the RH is selectively involved in processing negative emotions, pessimistic thoughts and unconstructive thinking styles--all which comprise the cognitive phenomenology of depression and in turn contribute to the elevated anxiety, stress and pain associated with the illness. Additionally, the RH mediates vigilance and arousal which may explain the sleep disturbances often reported in depression. The RH had also been linked with self-reflection, accounting for the tendency of depressed individuals to withdraw from their external environments and focus attention inward. Physiologically, RH activation is associated with hyprecortisolemia, which contributes to the deterioration of the immune system functioning and puts depressed patients at a greater risk of developing other illnesses, accounting for depression's high comorbidity with other diseases. Conversely, the LH is specifically involved in processing pleasurable experiences, and its relative attenuation is in line with the symptoms of anhedonia that characterize depression. The LH is also relatively more involved in decision-making processes, accounting for the indecisiveness that is often accompanied with depression.

Line bisection performance in patients with generalized anxiety disorder and treatment-resistant depression

BACKGROUND AND OBJECTIVES

The line bisection error to the left of the true center has been interpreted as a relative right hemisphere activation, which might relate to the subject's emotional state. Considering that patients with generalized anxiety disorder (GAD) or treatment-resistant depression (TRD) often have negative emotions, we hypothesized that these patients would bisect lines significantly leftward.

METHODS

We tried the line bisection task in the right-handed healthy volunteers (n = 56), GAD (n = 47) and TRD outpatients (n = 52). Subjects also completed the Zuckerman - Kuhlman Personality Questionnaire, the Zuckerman Sensation Seeking Scales, and the Plutchik-van Praag Depression Inventory.

RESULTS

GAD patients scored highest on the Neuroticism-Anxiety trait, TRD patients scored highest on depression, and both patients scored lower on the Sociability trait. Patients with GAD also bisected lines significantly leftward compared to the healthy subjects. The Frequency of the bisection error was negatively correlated with Disinhibition-Seeking in the healthy subjects, and with Total sensation-seeking and Experience-Seeking in GAD patients, while the Magnitude of the line bisection error was negatively correlated with depression in TRD patients.

CONCLUSIONS

The study suggests a stronger right hemispheric activation, a weaker left activation, or both in the GAD, instead of TRD patients.

Sexually dimorphic gray matter volume reduction in patients with panic disorder

While clinical features of panic disorder show significant sexual dimorphism, previous structural MRI studies have not sufficiently controlled for sex when looking at regional brain abnormalities in panic disorder. Using optimized voxel-based morphometry (VBM), regional gray matter volume was compared between 24 patients (male/female: 9/15) with panic disorder and 24 healthy subjects matched for age and sex. Significant gray matter volume reductions were found in the bilateral dorsomedial and right ventromedial prefrontal cortices, right amygdala, anterior cingulate cortex, bilateral insular cortex, occipitotemporal gyrus and left cerebellar vermis in the patients compared with the controls. Among these regions, the VBM revealed significant sexual dimorphism: volume reduction in the right amygdala and the bilateral insular cortex was significantly greater in the males, while reduction in the right superior temporal gyrus was greater in females. Furthermore, a significant reduction in the dorsolateral and ventrolateral prefrontal cortices, thalamus, and parietal cortex was specific to the female patients. The present study demonstrated the morphological changes in extensive brain regions of patients with panic disorder compared with the sex-matched controls. The current results further suggested that the sexually dimorphic clinical phenotypes of panic disorder might have a neurobiological background even at the structural level of the brain.

Panic disorder: is the PAG involved?

Data from studies with humans have suggested that abnormalities of midbrain structures, including the periaqueductal gray matter (PAG), could be involved in the neurobiology of panic disorder (PD). The electrical stimulation of the PAG in neurosurgical patients induces panic-like symptoms and the effect of drugs that are effective in the treatment of PD in the simulation of public speaking model of anxiety is in agreement with data from animal models of PD. Structural neuroimaging studies have shown increases in gray matter volume of midbrain and pons of PD patients. There is also evidence of lower serotonin transporter and receptor binding, and increases of metabolism in the midbrain of PD patients. Nevertheless, these midbrain abnormalities can not be considered as specific findings, since neuroimaging data indicate that PD patients have abnormalities in other brain structures that process fear and anxiety.

Pharmacological models in healthy volunteers: their use in the clinical development of psychotropic drugs

Animal models of diseases are widely used in the preclinical phase of drug development. They have a place in early human clinical psychopharmacology as well, in order to get early clues that contribute to establish the proof of concept (POC) already in healthy volunteers (HV). Different types of models are available (pharmacological or non-pharmacological provocation, models based on age-related characteristics). This review is focused on pharmacological models in HV, with the aim to identify the main issues raised by their use in pharmaceutical trials. The available models unevenly fulfil the requirements of face validity, sufficient response rate, test-retest consistence and responsiveness to reference drugs. Most of them have been developed in the purpose of pathophysiology studies, using rating instruments validated for clinical practice. Substantial progress could be made by adapting models to the specific requirements of pharmaceutical trials, including wider use of biomarkers. Characteristics that make models, as well as biomarkers, suitabLe for use in drug development are proposed. Despite obvious limitations, human models can significantly enhance the way phase I studies contribute to establish the POC, provided they are integrated into adapted phase I development plans. Their use as industrial tools for drug evaluation requires specific, dedicated development.

Challenge studies in anxiety disorders

In psychiatry, the use of pharmacological challenges in panic disorder is unique in that the clinical phenomenon of central interest (i.e., the panic attack) can be provoked readily and assessed in the clinical laboratory setting. During the past 20 years pharmacological challenge studies have increased our knowledge concerning the neurobiology of panic disorder remarkably and may ultimately result in novel and more causal treatment strategies. Moreover, the differences in sensitivity to certain panicogens such as serotonergic agents, lactate, carbon dioxide and cholecystokinin tetrapeptide are likely to be fruitful in serving as biological markers of subtypes of panic disorders and should be a major focus of research, as the identification of reliable endophenotypes is currently one of the major rate-limiting steps in psychiatric genetic studies.

Reduced brain serotonin transporter binding in patients with panic disorder

There is strong evidence for the importance of the serotonin (5-HT) system in the neurobiology of panic disorder (PD); however, the exact role of this system remains unclear. The 5-HT transporter (5-HTT) is a key element in 5-HT neurotransmission. The current study aimed to investigate the binding of 5-HTT in the brain of patients with PD. We used single-photon emission computed tomography with a radioligand that specifically labels the 5-HTT, [(123)I]nor-beta-CIT. Subjects comprised eight patients with current PD, eight patients with PD in remission, and eight healthy control subjects. The patients with current PD showed a significant decrease in 5-HTT binding in the midbrain, in the temporal lobes and in the thalamus in comparison to the controls. The binding of 5-HTT in patients with PD in remission was similar to findings in the control group in the midbrain and in the temporal lobes, but lower in the thalamus. Regional 5-HTT binding significantly and negatively correlated with the severity of panic symptoms. These findings point to a dysregulation of the 5-HT system in PD patients. Altered function of 5-HTT appears to be related to the clinical status of patients. Clinical improvement in the patients in remission is associated with normalization of 5-HTT binding.

Neuroanatomical circuits modulating fear and anxiety behaviors

OBJECTIVE

Our understanding of the neurobiology of anxiety disorders, although not complete, has advanced significantly with the development and application of genetic, neuroimaging and neurochemical approaches.

METHOD

The neuroanatomical basis of anxiety disorders is reviewed with particular focus on the amygdala and the temporal and prefrontal cortex. The functional anatomical correlates of anxiety disorders such as panic disorder, specific phobias and post-traumatic stress disorder are also discussed.

RESULTS

Functional neuroimaging studies in patients with anxiety disorders have shown neurophysiological abnormalities during symptom provocation tests, implicating the limbic, paralimbic and sensory association regions. The involvement of neurotransmitters such as serotonin and norepinephrine in depressive disorders is well established. Antidepressants that affect these neurotransmitter systems have also been shown to be useful in the treatment and management of patients with anxiety disorders. The role of serotonin and norepinephrine in the pathophysiology of anxiety disorders is reviewed. In addition, the involvement of the stress hormone corticotropin-releasing hormone, the peptide cholecystokinin and the amino acid transmitter gamma-amino butyric acid in anxiety disorders is reviewed.

CONCLUSION

The inconsistency in the results of biologic investigations of anxiety disorders highlights the importance of addressing the neurobiologic heterogeneity inherent within criteria-based, psychiatric diagnoses. Understanding of this heterogeneity will be facilitated by the continued development and application of genetic, neuroimaging and neurochemical approaches that can refine anxiety disorder phenotypes and elucidate the genotypes associated with these disorders. Application of these experimental approaches will also facilitate research aimed at clarifying the mechanisms of anti-anxiety therapies.

Cortical neurophysiology of anticipatory anxiety: an investigation utilizing steady state probe topography (SSPT)

The precise role of the cortex in human anxiety is not well characterised. Previous imaging research among healthy controls has reported alterations in regional cerebral blood flow (rCBF) within the prefrontal and temporal cortices during periods of anxious anticipation; however, the temporal dynamics of this activity has yet to be examined in detail. The present study examined cortical Steady State Probe Topography (SSPT) changes associated with anticipatory anxiety (AA), allowing examination of the temporal continuity and the excitatory or inhibitory nature of AA activations. We recorded Steady State Visually Evoked Potentials (SSVEPs) at 64 scalp locations, skin conductance, and self reported anxiety among 26 right-handed males while relaxed and during the anticipation of an electric shock. Relative to the baseline condition, the AA condition was associated with significantly higher levels of self-reported anxiety and increased phasic skin conductance levels. Across the seven second imaging window, AA was associated with increased SSVEP latency within medial anterior frontal, left dorsolateral prefrontal and bilateral temporal regions. In contrast, increased SSVEP amplitude and decreased SSVEP latency were observed within occipital regions. The observed SSVEP latency increases within frontal and temporal cortical regions are suggestive of increased localised inhibitory processes within regions reciprocally connected to subcortical limbic structures. Occipital SSVEP latency decreases are suggestive of increased excitatory activity. SSVEP amplitude increases within occipital regions may be associated with an attentional shift from external to internal environment. The current findings provide further support for the involvement of frontal, anterior temporal, and occipital cortical regions during anticipatory anxiety, and suggest that both excitatory and inhibitory processes are associated with AA alterations.

Cognitive ERPs in depressive and anxiety disorders during tonal and phonetic oddball tasks

This report compares event-related brain potentials (ERPs) of patients having a depressive disorder alone (n = 58), an anxiety disorder alone (n = 22), comorbidity of these disorders (n = 18), and healthy controls (n = 49). ERPs were recorded from 30 electrode sites during auditory oddball tasks using consonant-vowel syllables (phonetic) or complex tones (tonal). Overlapping ERP components were identified and measured using covariance-based principal components analysis. An early P3 subcomponent (P315) was larger in patients having an anxiety disorder alone when compared to depressed patients with or without an anxiety disorder and healthy controls, whereas a late P3 subcomponent (P400) was larger in patients having comorbidity of anxiety and depressive disorders than in the other groups. Also, the N2-P3 complex showed task-dependent hemispheric asymmetries, including larger N2-P3 amplitude over left than right temporoparietal sites during the phonetic oddball task. This hemispheric asymmetry was greatest in patients having a depressive disorder alone and smallest in patients having an anxiety disorder alone. The opposite nature of the alterations of hemispheric asymmetry and early P3 amplitude in depressive and anxiety disorders underscores the importance of taking comorbidity with anxiety into account in studies of cognitive ERPs in depressive disorders.

Functional MRI changes during panic anticipation and imagery exposure

While undergoing fMRI, six patients with DSM IV diagnosis of panic disorder and six normal controls performed directed imagery of neutral, moderate and high anxiety situations based on an individually determined behavioral hierarchy. Brain activity was compared during high vs neutral anxiety blocks for each group of subjects using SPM99b. Panic patients showed increased activity in inferior frontal cortex, hippocampus and throughout the cingulate both anterior and posterior, extending into the orbitofrontal cortex and encompassing both hemispheres. These areas may constitute the important circuit in the psychopathology of panic disorder. We propose that this pattern of activity may enhance the encoding and retrieval of strong emotional events, facilitating the recapitulation of traumatic experiences and leading to panic disorder in vulnerable individuals.

Brain metabolic changes associated with symptom factor improvement in major depressive disorder

BACKGROUND

Symptoms of major depressive disorder (MDD) have been linked to regional brain function through imaging studies of symptom provocation in normal control subjects and baseline studies of subjects with MDD. We examined associations between change in depressive symptom factors and change in regional brain metabolism from before to after treatment of MDD.

METHODS

Thirty-nine outpatients with MDD underwent 18F-fluorodeoxyglucose positron emission tomography scanning before and after treatment with either paroxetine or interpersonal psychotherapy. Associations were determined between changes in regional brain metabolism and changes in four Hamilton Depression Rating Scale factors (anxiety/somatization [ANX], psychomotor retardation [PR], cognitive disturbance [COGN], and sleep disturbance) and two corresponding Profile of Mood States subscales (tension [TENS] and fatigue [FATIG]).

RESULTS

Improvement in ANX, PR, TENS, and FATIG factors was associated with decreasing ventral frontal lobe metabolism. Improvement in ANX and TENS was also associated with decreasing ventral anterior cingulate gyrus (AC) and anterior insula activity, whereas improvement in PR was associated with increasing dorsal AC activity. COGN improvement was associated with increasing dorsolateral prefrontal cortex metabolism.

CONCLUSIONS

Brain regions that show significant relationships with symptom provocation in normal control subjects have similar relationships with MDD symptoms as they improve with treatment.