The anatomy of melancholia: does frontal-subcortical pathophysiology underpin its psychomotor and cognitive manifestations?

Clinical Characteristics of Melancholic and Nonmelancholic Depressions

ABSTRACT

This study aimed to compare clinical-demographic features of melancholic and nonmelancholic depressions. We included 141 depressed inpatients classified as melancholic and nonmelancholic by the Sydney Melancholia Prototype Index (SMPI) and Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) criteria. Results were controlled for confounders, including severity measures. Melancholic patients by both diagnostic systems were more severely depressed and presented more psychotic symptoms, neurological soft signs, and psychomotor disturbances. Melancholic patients classified by the SMPI were also older at illness onset and had fewer suicide attempts. After controlling for confounders, although all differences remained significant for SMPI diagnosis, the DSM-5 diagnosis of melancholia was only associated with further impaired motor sequencing. The results obtained with the SMPI support the hypothesis that melancholia has clinical features qualitatively different from those of nonmelancholic depressions. Contrarily, the DSM-5 specifier seems to reflect the severity of depressive episodes rather than core clinical features of melancholia.

Reduced tract length of the medial forebrain bundle and the anterior thalamic radiation in bipolar disorder with melancholic depression

BACKGROUND

The supero-lateral medial forebrain bundle (slMFB) and the anterior thalamic radiation (ATR) play a core role in reward anticipation and motivational processes. In this study, the slMFB and the ATR were investigated in a group of depressed bipolar disorder (BD) and in healthy controls (HC) using tract length as a measure of fibre geometry and fractional anisotropy (FA) as a measure of white matter microstructure. We hypothesized reduced tract length and FA of the slMFB and the ATR in BD. We expect alterations to be driven by the melancholic subtype.

METHODS

Nineteen depressed patients with BD and 19 HC matched for age and gender underwent diffusion-weighted magnetic resonance imaging (MRI) scans. Diffusion tensor imaging (DTI) based tractography was used to reconstruct bilateral slMFB and ATR. Mean tract length and FA were computed for the slMFB and the ATR. Mixed-model ANCOVAs and post-hoc ANCOVAs, controlling for age and intracranial volume, were used to compare tract length and FA of bilateral slMFB and ATR between HC and BD and between HC and subgroups with melancholic and non-melancholic symptoms.

RESULTS

In BD we found a significantly shortened tract length of the right slMFB and ATR in BD compared to HC. Subgroup analyses showed that these findings were driven by the melancholic subgroup. Mean-FA did not differ between HC and BD.

LIMITATIONS

Sample size CONCLUSIONS: Tract length of the right slMFB and the right ATR is reduced in BD. Those changes of fibre geometry are driven by the melancholic subtype.

Cognitive and emotional biomarkers of melancholic depression: An iSPOT-D report

BACKGROUND

Depressed patients with melancholic features have distinct impairments in cognition and anhedonia, but it remains unknown whether these impairments can be quantified on neurocognitive biomarker tests of behavioral performance. We compared melancholic major depressive disorder (MDD) patients to non-melancholic MDD patients and controls on a neurocognitive test battery that assesses eight general and emotional cognitive domains including the hypothesized decision-making and reward-threat perception.

METHODS

MDD outpatients (n=1008) were assessed using a computerized battery of tests. MDD participants met DSM-IV criteria for MDD and had a score ≥16 on the 17-item Hamilton Rating Scale for Depression. Melancholic MDD was defined using the Mini-International Neuropsychiatric Interview and a psychomotor disturbance observer-rated CORE measure score >7. Controls were age- and gender-matched with no previous DSM-IV or significant medical history.

RESULTS

Melancholic participants (33.7% of the MDD sample) exhibited significantly poorer performance than controls across each domain of cognitive function and for speed of emotion identification and implicit emotion priming. Compared to the non-melancholic group, specific disturbances were seen on tests of information speed, decision speed, and reward-relevant emotional processing of happy expressions, even after co-varying for symptom severity.

LIMITATIONS

Assessments were taken at only one medication-free time point. Reward was investigated using an emotional faces task.

CONCLUSIONS

Melancholic MDD is distinguished by a specific neurocognitive marker profile consistent with reduced decision-making capacity under time demands and loss of reward sensitivity. This profile suggests an underlying deficit in mesolimbic-cortical circuitry for motivationally-directed behavior.

White matter microstructure alterations of the medial forebrain bundle in melancholic depression

BACKGROUND

The medial forebrain bundle (MFB) is a key structure of the reward system and connects the ventral tegmental area (VTA) with the nucleus accumbens (NAcc), the medial and lateral orbitofrontal cortex (mOFC, lOFC) and the dorsolateral prefrontal cortex (dlPFC). Previous diffusion tensor imaging (DTI) studies in major depressive disorder point to white matter alterations of regions which may be incorporated in the MFB. Therefore, it was the aim of our study to probe white matter integrity of the MFB using a DTI-based probabilistic fibre tracking approach.

METHODS

22 patients with major depressive disorder (MDD) (12 melancholic-MDD patients, 10 non-melancholic-MDD patients) and 21 healthy controls underwent DTI scans. We used a bilateral probabilistic fibre tracking approach to extract pathways between the VTA and NACC, mOFC, lOFC, dlPFC respectively. Mean fractional anisotropy (FA) values were used to compare structural connectivity between groups.

RESULTS

Mean-FA did not differ between healthy controls and all MDD patients. Compared to healthy controls melancholic MDD-patients had reduced mean-FA in right VTA-lOFC and VTA-dlPFC connections. Furthermore, melancholic-MDD patients had lower mean-FA than non-melancholic MDD-patients in the right VTA-lOFC connection. Mean-FA of these pathways correlated negatively with depression scale rating scores.

LIMITATIONS

Due to the small sample size and heterogeneous age group comparisons between melancholic and non-melancholic MDD-patients should be regarded as preliminary.

CONCLUSIONS

Our results suggest that the melancholic subtype of MDD is characterized by white matter microstructure alterations of the MFB. White matter microstructure is associated with both depression severity and anhedonia.

Discriminating melancholic and non-melancholic depression by prototypic clinical features

BACKGROUND

Melancholia is positioned as either a more severe expression of clinical depression or as a separate entity. Support for the latter view emerges from differential causal factors and treatment responsiveness but has not been convincingly demonstrated in terms of differential clinical features. We pursue its prototypic clinical pattern to determine if this advances its delineation.

METHODS

We developed a 24-item measure (now termed the Sydney Melancholia Prototype Index or SMPI) comprising 12 melancholic and 12 non-melancholic prototypic features (both symptoms and illness correlates). In this evaluative study, 278 patients referred for tertiary level assessment at a specialized mood disorders clinic completed the self-report SMPI as well as a depression severity measure and a comprehensive assessment schedule before clinical interview, while assessing clinicians completed a clinician version of the SMPI items following their interview. The independent variable (diagnostic gold standard) was the clinician's judgment of a melancholic versus non-melancholic depressive episode. Discriminative performance was evaluated by Receiver Operating Characteristics (ROC) analysis of four strategies for operationalising the SMPI self-report and SMPI clinician measures, and with the former strategies compared to ROC analysis of the depression severity measure. The external validity of the optimally discriminating scores on each measure was tested against a range of clinical variables.

RESULT

Comparison of the two self-report measures established that the SMPI provided greater discrimination than the depression severity measure, while comparison of the self-report and clinician-rated SMPI measures established the latter as more discriminating of clinically diagnosed melancholic or non-melancholic depression. ROC analyses favoured self-report SMPI distinction of melancholic from non-melancholic depression being most optimally calculated by a 'difference' score of at least four or more melancholic than non-melancholic items being affirmed (sensitivity of 0.69, specificity of 0.77). For the clinician-rated SMPI measure, ROC analyses confirmed the same optimal difference score of four or more as highly discriminating of melancholic and non-melancholic depression (sensitivity of 0.84, specificity of 0.92). As the difference score had positive predictive values of 0.90 and 0.70 (for the respective clinician-rated and self-report SMPI forms) and respective negative predictive values of 0.88 and 0.70, we conclude that the clinician-rated version had superior discrimination than the self-report version. External validating data quantified the self-rated and clinician-rated Index-assigned non-melancholic patients having a higher prevalence of anxiety disorders, a higher number of current and lifetime stressors, as well as elevated scores on several personality styles that are viewed as predisposing to and shaping such non-melancholic disorders.

LIMITATIONS

Assigned melancholic and non-melancholic diagnoses were determined by clinician judgement, risking a circularity bias across diagnostic assignment and clinical weighting of melancholic and non-melancholic features. The robustness of the Index requires testing in primary and secondary levels of care settings.

CONCLUSIONS

The clinician-rated SMPI differentiated melancholic and non-melancholic depressed subjects at a higher level of confidence than the self-report SMPI, and with a highly acceptable level of discrimination. The measure is recommended for further testing of its intrinsic and applied properties.

Cross-sectional and longitudinal assessment of structural brain alterations in melancholic depression

BACKGROUND

Whole-brain imaging approaches may contribute to the characterization of neuroanatomic alterations in major depression, especially in clinically homogenous patient groups such as those with melancholic features. We assessed brain anatomic alterations, both cross-sectionally and longitudinally, in patients with melancholic depression using a whole-brain voxel-wise approach.

METHODS

Whole-brain magnetic resonance images were collected from a relatively aged sample of 70 consecutively recruited major depressive disorder inpatients with melancholic features and from a group of 40 healthy control subjects. All patients were clinically followed for at least 2 years, and a subset of 30 depressive patients and 20 control subjects were rescanned after a 7-year period. Imaging data were analyzed with voxel- and tensor-based morphometry techniques.

RESULTS

Melancholic patients showed gray matter reductions in the left insula and white matter increases in the upper brainstem tegmentum. Male patients showed gray matter decreases in the right thalamus, and periventricular white matter reductions were specifically observed in older patients. Volume decreases in the left insula, hippocampus, and lateral parietal cortex predicted a slower recovery after treatment initiation. In longitudinal assessment, white matter of the upper brainstem tegmentum showed a different temporal evolution between groups. Additionally, bilateral gray matter reductions in the insulae were associated with the number of relapses during follow-up.

CONCLUSIONS

Structural alterations were identified in regions potentially related to relevant aspects of melancholia pathophysiology. Longitudinal analyses indicated region-specific interactions of baseline alterations with age as well as a significant association of clinical severity with focal changes occurring over time.

Light to moderate alcohol drinking is associated with higher cognitive function in males with type 2 diabetes

This study examined cognitive function in males with type 2 diabetes who drank light to moderate levels of alcohol in comparison to abstainers. Patients who abstained from alcohol use (Abstainer; N = 99) were compared to patients who were current drinkers (Drinker; N = 20) with respect to demographic, clinical, and cognitive variables. There were no significant differences between the Drinker and Abstainer groups in demographic and general clinical variables (p values > .05). After controlling for various potential confounding variables including age, education level, number of years diagnosed with diabetes, hemoglobin A1c (HbA1c), hypertension status, and depression, multivariate analysis of covariance (MANCOVA) showed that the Drinker group performed significantly better than the Abstainer group, specifically on three of five cognitive tests - Digit Span Backward, Digit Symbol, and Trail Making B (p values < .05). Our findings suggest that light to moderate alcohol consumption, up to two drinks per day, is associated with relatively higher cognitive function in males with type 2 diabetes.

Negative symptoms: A review of schizophrenia, melancholic depression and Parkinson's disease

Negative symptoms generally refer to a reduction in normal functioning. In schizophrenia they encompass apathy, anhedonia, flat affect, avolition, social withdrawal and, on some accounts, psychomotor retardation. Negative symptoms have been identified in other psychiatric disorders, including melancholic depression, and also in neurological disorders, such Parkinson's disease. Achieving a better understanding of negative symptoms constitutes a priority in mental health. Primarily, negative symptoms represent an unrelenting, intractable and disabling feature for patients, often amounting to a severe burden on families, carers and the patients themselves. Identifying and understanding subgroups within disorders may also contribute to the clinical care and scientific understanding of the pathophysiology of these disorders. The purpose of this paper is to review the current literature on negative symptoms in schizophrenia and explore the idea that negative symptoms may play an important role not only in other psychiatric disorders such as melancholic depression, but also in neurological disorders, such as Parkinson's disease. In each disorder negative symptoms manifest with similar motor and cognitive impairments and are associated with comparable neuropathological and biochemical findings, possibly reflecting analogous impairments in the functioning of frontostriatal-limbic circuits.

Ocular motor differences between melancholic and non-melancholic depression

BACKGROUND

Major depressive disorder may be a heterogeneous disorder, yet melancholic depression is the most consistently described subtype, regarded as qualitatively different to non-melancholic depression in terms of cognitive and motor impairments. Eye movement studies in depression are infrequent and findings are inconclusive.

METHODS

This study employed a battery of saccadic eye movement tasks to explore reflexive saccades, as well as higher order cognitive aspects of saccades including inhibitory control and spatial working memory. Nineteen patients with major depressive disorder (9 melancholic; 10 non-melancholic) and 15 healthy controls participated.

RESULTS

Differences were revealed between melancholic and non-melancholic patients. Melancholia was associated with longer latencies, difficulty increasing peak velocities as target amplitudes increased, and hypometric primary saccades during the predictable protocol. In contrast, the non-melancholic depression group performed similarly to controls on most tasks, but saccadic peak velocity was increased for reflexive saccades at larger amplitudes.

LIMITATIONS

Most patients were taking antidepressant medication.

CONCLUSIONS

The latency increases, reduced peak velocity and primary saccade hypometria with more severe melancholia may be explained by functional changes in the fronto-striatal-collicular networks, related to dopamine dysfunction. In contrast, the serotonergic system plays a greater role in non-melancholic symptoms and this may underpin the observed increases in saccadic peak velocity. These findings provide neurophysiological support for functional differences between depression subgroups that are consistent with previous motor and cognitive findings.

When euthymia is just not good enough: the neuropsychology of bipolar disorder

Bipolar disorder (BD) is a debilitating psychiatric illness that is uniquely characterized by switching between psychopathologically contrasting phases of mania and depression, often with intervening periods of euthymia. However, these periods of apparent clinical recovery (euthymia) are marked by subtle social, occupational, and cognitive impairments, profiled by recent neuropsychological investigations. Determining the cognitive changes across these three phases may help differentiate the disruptions that are mood state-dependent from those associated with underlying pathology. This article therefore critically reviews the reported neuropsychological impairments in BD and the methodological limitations facing such research. Integration of the available evidence, principally from the field of neuropsychology, when synthesized, implicates the prefrontal cortex in the etiopathogenesis of BD and posits cortical-subcortical-limbic disruption in recovered euthymic patients that manifests as cognitive dysfunction.

The relationship between type 2 diabetes and cognitive dysfunction: longitudinal studies and their methodological limitations

Type 2 diabetes and dementia in the elderly are major public health problems. Cross-sectional studies have suggested that these two conditions may be inter-related, but the nature of this association is uncertain. Causation can only be established through studies with a longitudinal design, taking into account the many potential confounding factors in any study of cognition. A literature search has identified 10 studies (nine population-based and one of case-controlled design) that included a definable diabetic population and assessments of cognitive function at baseline and at follow-up. These 10 studies utilised a combination of domain-specific cognitive assessments and a clinical diagnosis of dementia in the assessment of cognitive function. Diabetes was associated with either an accelerated cognitive decline or an increased incidence of dementia in eight of nine of the population-based studies. One study demonstrated a relationship between diabetes and vascular cognitive impairment, but not with other types of dementia. No association between type 2 diabetes and cognitive decline was demonstrated in the case-controlled study. These studies provide compelling evidence to support the view that people with type 2 diabetes are at increased risk of developing cognitive impairment in comparison with the general population.

Executive and prefrontal dysfunction in unipolar depression: a review of neuropsychological and imaging evidence

This paper reviews recent empirical findings related to prefrontal and executive function in unipolar depression. While a number of reviews have dealt with either the neuropsychological literature or findings from imaging studies, the present review addresses both, as well as findings from studies that have combined brain-imaging techniques with neuropsychological measures. This combined approach is of great interest as the performance of a structured task may act to load the areas of interest and reduce variance, thus making the imaging evidence more valuable; while the use of imaging provides a check that the neuropsychological tasks are indeed engaging the structures whose performance they are intended to assess. Prominent models of the neurobiology of depression implicate involvement of the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC). The evidence from combined imaging and neuropsychological studies supports the involvement of the ACC, but is less clear in the case of the DLPFC. However, the limited number of such studies conducted to date means that conclusions must be tentative and further studies employing this combined approach may be of great value.

Improvement of working but not declarative memory is correlated with HPA normalization during antidepressant treatment

Previous research demonstrated that depression is associated with hyperactivity of the hypothalamus-pituitary-adrenocortical (HPA) system after stimulation. There is also strong evidence that the modulation of corticosteroids in the brain induces memory dysfunction which represents core features of depression. Antidepressant treatment with serotonin reuptake inhibitors (SSRIs) alleviates both dysfunctions. Thus, these previous observations propose a correlation between treatment induced changes of the endocrinological response of the HPA system to challenge with dexamethasone and CRH and changes of memory functions during antidepressant treatment. This study explores the relationship between depression, memory functions and the responsiveness of the HPA system as assessed by the combined DEX/CRH test during antidepressant treatment in n = 64 patients with major depression during a four weeks treatment with citalopram. We found that treatment induced changes of the cortisol response pattern in the DEX/CRH test were correlated with improvement of working memory but not so with episodic memory, sustained attention or global severity of depression. We suggest that improvement of working memory is more sensitive to the changes of hormones of the HPA system (e.g. cortisol) than other cognitive functions and the global severity of depression.

Differential patterns of psychomotor functioning in unmedicated melancholic and nonmelancholic depressed patients

Few studies examining psychomotor retardation (PR) in patients with major depressive disorder (MDD) included medication-free patients. The purpose of this study was (1) to examine whether unmedicated patients with MDD would exhibit PR, (2) to determine whether this retardation, if present, was more cognitive or motor in nature, and (3) to investigate whether any differences in PR could be established between melancholic and nonmelancholic depressed patients. Thirty-eight unmedicated inpatients with severe MDD (20 melancholic and 18 nonmelancholic patients) and 38 matched controls were compared on figure-copying tasks in which the cognitive task difficulty was manipulated. In addition, a simple motor task and the symbol digit substitution task (SDST) were administered. As a group, the patients were significantly slower performing all tasks and both initiation times (IT) and movement times (MT) were prolonged. However, when a distinction was made between the two subtypes, only the melancholic patients showed prolonged MTs compared to the controls. Furthermore, the melancholic patients differed significantly from the controls in IT in all tasks. The nonmelancholic patients had significantly longer ITs than the controls in two copying tasks. It can be concluded that there was clear cognitive and motor slowing in this group of unmedicated inpatients with MDD. The melancholic patients were more severely affected than the nonmelancholic patients and showed a slowing of cognitive as well as motor processes. Differences in psychomotor functioning between melancholic and nonmelancholic depressed patients could imply different underlying neurobiological disturbances in these subtypes of major depression.

High psychiatric comorbidity in spasmodic torticollis: a controlled study

Disturbed body image and negative self-referent cognitions caused by the postural disfigurement of the head are regarded as the main reason for elevated depression scores in spasmodic torticollis (ST), but this factor was never controlled for. We therefore compared 48 patients with ST and 48 patients with alopecia areata (AA) who were matched for age, sex, and body image dissatisfaction. Psychiatric diagnoses were based on a structured psychiatric interview (SCID-I). Results of patients with ST and AA were compared with a matched sample of the representative German population. Odds ratios to develop psychiatric comorbidity for patients with ST compared with patients with AA were significantly increased throughout nearly all assessed DSM-IV categories. Logistic regression analysis showed that (1) depressive coping and (2) belonging to the group of patients with ST correlated with a significantly higher rate of current psychiatric diagnosis. We conclude that high psychiatric comorbidity in ST is unlikely to be a mere consequence of chronic disease and disfigurement.

Anatomic location and laterality of MRI signal hyperintensities in late-life depression

OBJECTIVES

Evidence is mounting linking cerebrovascular disease with the development of major depression in the elderly. Lesions in both white and gray matter have been associated with geriatric depression. In addition, the literature on poststroke depression suggests that left-sided lesions are associated with depression. We sought to examine the severity and location of white- and gray-matter lesions in a group of elderly depressives and nondepressed control subjects.

METHOD

115 depressed patients (69 with late onset, 46 with early onset) and 37 controls, all over age 45, received magnetic resonance imaging (MRI). Semiquantitative severity ratings and quantitative measurements of number and size of MRI hyperintensities were obtained, and groups were compared using Cochran-Mantel-Haenszel (CMH) analyses and repeated-measures analyses of covariance adjusting for age.

RESULTS

Late-onset depressed patients had more severe hyperintensity ratings in deep white matter than early-onset patients and controls. Late- and early-onset patients had more severe subcortical gray-matter hyperintensities (particularly in the putamen) compared with controls. Left-sided white-matter lesions were significantly associated with older age of depression onset, whereas right-anterior white matter and left-subcortical lesions (particularly in the putamen) were associated with melancholia in the depressed group.

CONCLUSION

These findings extend previous reports of an association between cerebrovascular disease and depression, as well as recent studies showing lateralized lesion involvement in geriatric depression. Such vascular pathology may disrupt neural pathways involved in affective processing and the maintenance of a normal mood and psychomotor state.

Event-related potentials and white matter lesions in bipolar disorder

OBJECTIVES

To investigate neurophysiological parameters which possibly distinguish subtypes I and II of patients with a bipolar disorder, and contrast the findings with observations from a group of schizophrenic patients and a group of healthy controls.

METHODS

Sixty-six volunteers underwent a MRI scan to determine the number and location of white matter lesions (WSL). A electrophysiological registration was made while all volunteers performed a auditory 'oddball' task, and the amplitude of the resulting P300 wave was compared.

RESULTS

Earlier reports of higher numbers of WSL in bipolar disorder were not replicated in this study. Subtypes I and II showed a different P300 amplitude and subtype I resembled the results of the schizophrenia group.

CONCLUSION

Bipolar patients in remission have a functional brain disorder that is expressed by a change in physiological response to external stimuli.

Effect of the treatment of Type II diabetes mellitus on the development of cognitive impairment and dementia

BACKGROUND

There is increasing interest in preventing cognitive impairment and dementia in later life. Epidemiological evidence shows a relationship between cognitive impairment and Type II diabetes. This association is stronger in patients who have been diagnosed for longer periods of time and in those who are on insulin therapy. There is little information on the short- and long-term influence of type of treatment and level of metabolic control on cognitive function of people with diabetes.

OBJECTIVES

To assess the effects of different types and intensities of treatments for Type II diabetes on cognitive function.

SEARCH STRATEGY

The Cochrane Control Trials Register, MEDLINE, EMBASE, PsycINFO, SIGLE LILACS and CINAHL as well as a number of ongoing trials databases were searched on 11 June 2002 using appropriate strategies.

SELECTION CRITERIA

Randomized controlled trials in which different treatments for Type II diabetes have been compared and in which measures of cognitive function were made at entry and after the treatment.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality. Five trials were identified for possible inclusion but none of them could be included. In one, cognitive function was assessed before and after intensive or conventional diabetic treatment, but the comparison was not double-blind. The three other studies explored the effect of different treatments on QOL but did not include appropriate evaluation of cognitive function. The fifth did not report baseline data on cognitive function in the trial groups.

MAIN RESULTS

No studies were found to be appropriate for inclusion in meta-analysis.

REVIEWER'S CONCLUSIONS

There is no convincing evidence relating type or intensity of diabetic treatment to the prevention or management of cognitive impairment in Type II diabetes. Future research on treatments for diabetes should include standardized assessments of cognitive function as outcome measures.

Cognitive deficits in depression: possible implications for functional neuropathology

BACKGROUND

While depression is known to involve a disturbance of mood, movement and cognition, its associated cognitive deficits are frequently viewed as simple epiphenomena of the disorder.

AIMS

To review the status of cognitive deficits in depression and their putative neurobiological underpinnings.

METHOD

Selective computerised review of the literature examining cognitive deficits in depression and their brain correlates.

RESULTS

Recent studies report both mnemonic deficits and the presence of executive impairment--possibly selective for set-shifting tasks--in depression. Many studies suggest that these occur independent of age, depression severity and subtype, task 'difficulty', motivation and response bias: some persist upon clinical 'recovery'.

CONCLUSIONS

Mnemonic and executive deficits do no appear to be epiphenomena of depressive disorder. A focus on the interactions between motivation, affect and cognitive function may allow greater understanding of the interplay between key aspects of the dorsal and ventral aspects of the prefrontal cortex in depression.

Effect of apomorphine on motor and cognitive function in melancholic patients: a preliminary report

Given the many clinical parallels between melancholia and disorders associated with impaired dopaminergic function such as Parkinson's Disease (PD), it has been hypothesised that major depressive disorder, and in particular the psychomotor features of melancholic depression, may also be associated with a hypodopaminergic state. If this is the case, then the use of a dopamine agonist might lead to reversal of both the cognitive and motor impairments seen in these patients. A double-blind, placebo-controlled cross-over design was used to test the effect of apomorphine on motor and cognitive function in seven melancholic subjects (as defined by the CORE instrument) and five control subjects. The testing battery included the following items: finger tapping, rapid alternating movements, verbal fluency, Rey Auditory Verbal Learning Task, digit symbol substitution task and simple and complex reaction times. The independent t-test, after covarying for age, revealed significant impairment in melancholic subjects for the walking task and digit symbol substitution at baseline. Results of the ANCOVA revealed no impact of time or drug condition, either alone or in combination, upon task performance in either group whether assessed separately or jointly. Results of a MANCOVA revealed that apomorphine impaired performance on some cognitive tasks, and that this was seen to a lesser extent in melancholics than control subjects. There was no evidence that the dopamine agonist apomorphine improved cognitive or motor function in subjects with strictly defined melancholia, suggesting that psychomotor retardation is not associated with a hypodopaminergic state. Our conclusions, however, were limited by small sample size; minimal baseline task impairment in depressed compared to control subjects; mild sedation in many subjects during task performance; and lack of serum apomorphine levels.

Neuropsychological functioning in patients with borderline personality disorder

Although results have been variable, studies suggest that individuals with borderline personality disorder (BPD) exhibit cognitive deficits suggestive of frontal- and temporal-lobe dysfunction. Patients diagnosed with BPD (n = 18) using two structured interviews, and who were carefully screened for neurological and substance-use disorders, were compared to depressed patients (n = 18) and a nonpsychiatric control group (n = 18) on a series of neuropsychological tasks. The role of emotion on cognitive functioning was assessed by including emotional stimuli and interference on several of the tasks. Little support was found for the neurobehavioral hypothesis of BPD. The BPD group performance did not differ from the normal group on most tasks of executive functioning or memory, and the introduction of emotional stimuli did not impair performance. The depressed group performed less effectively than the other groups. Reasons for variable findings and factors affecting the cognitive functioning of patients with BPD are discussed. There may be considerable heterogeneity in the cognitive functioning of BPD patients, with those exhibiting significant cognitive deficits comprising only a subgroup.

Dual voxel proton magnetic resonance spectroscopy in the healthy elderly: subcortical-frontal axonal N-acetylaspartate levels are correlated with fluid cognitive abilities independent of structural brain changes

The published literature suggests that degeneration of the subcorticofrontal networks may underlie cognitive ageing, but appropriate methods to examine this in vivo have been lacking. Proton Magnetic Resonance Spectroscopy ((1)H-MRS) has now been used in a number of clinical studies to assess cerebral pathophysicochemistry and recently has been utilized to examine the relationship between neurochemical markers and cognitive functioning in normal individuals. Results have been somewhat conflicting and difficult to interpret. To further clarify the role of the cognitive spectroscopy technique, we measured N-acetylaspartate (NAA) levels in the frontal subcortical white matter and the occipitoparietal grey matter and correlated them with performance in different cognitive domains in a group of twenty healthy elderly individuals. Subjects underwent whole brain T(1)- and T(2)-weighted magnetic resonance imaging (MRI), dual voxel short echo-time (1)H-MRS, and a comprehensive neuropsychological assessment. Individual tests of executive and attentional abilities, and a principal components composite score reflecting these skills, but not measures of memory or verbal abilities, were correlated with NAA concentration in the frontal white matter only. These relationships were independent of other neurocognitive predictors of executive impairment such as age, midventricular dilation, frontal white matter disease, and presenescent verbal proficiency. This study suggests the ability of (1)H-MRS to differentiate anatomically distinct neurochemical markers related to specific cognitive abilities. In particular, neurometabolic fitness of the frontal subcortical-cortical axonal fibers may be important in mediating fluid intellectual processing. Longitudinal MRS studies are required to determine if the present results reflect different rates of neurocellular degeneration or preexisting individual differences in neuronal density.

Habituation of the blink reflex in first-episode schizophrenia, psychotic depression and non-psychotic depression

OBJECTIVE

Electrophysiological recording of the electrically elicited blink reflex is the most reliable method of investigating habituation of the startle reflex. The purpose of this study was to compare the habituation and the late R3-component of the blink reflex between control subjects (N=19) and first-episode patients with schizophrenia (N=17), psychotic depression (N=23), and severe non-psychotic depression (N=25).

METHODS

The blink reflex was evoked by electrical stimulation of the supraorbital nerve, and the deficient habituation of the R2i-component was measured with a computer-assisted integral area measurement. Prefrontal executive function of the patients was assessed with the Wisconsin Card Sorting Test. Current psychiatric symptoms were assessed with the Brief Psychiatric Rating Scale, the Hamilton Depression Scale, the Positive and Negative Syndrome Scale, and the Calgary Depression Scale.

RESULTS

Deficient habituation of the blink reflex and occurrence of the late R3 component were associated both with a previous diagnosis of psychotic disorder and with the presence of current psychosis. The sensitivity and specificity of the abnormal habituation of the blink reflex in detecting psychotic disorder were 0.50 and 0.80, respectively. The abnormalities of the blink reflex were not associated with psychotropic medication. In schizophrenic patients, defective habituation of the blink reflex was associated with negative and cognitive symptoms, and in depressive patients with the presence of delusions.

CONCLUSIONS

The deficient habituation of the blink reflex and occurrence of the late R3 component seem to be both trait and state markers of a psychotic disorder. The results suggest that schizophrenia and psychotic depression share some common neurobiological mechanisms involved in the modulation of the startle reflex.

Quantitative assessment of dynamic electroencephalogram (EEG) organization as a tool for subtyping depressive syndromes

Up until now, no subclassification of affective psychoses has been validated biologically. This follows unavoidably from a research practice of defining diagnostic subtypes in consensus conferences and only thereafter allowing their validation. There is evidence that electroencephalograms (EEG) may be a useful tool in psychiatry, provided that the relevant information is extracted. Our EEG quantification procedure aims at an assessment of both the amount and range of variation of spontaneous changes of topographical alpha-power distribution, developing within a certain period of recording under resting conditions. Our measures were designed to characterize the dynamic organization of the EEG. This is quite obviously an eyeball evaluation but it has nevertheless been neglected in research. The study design was done retrospectively. Included were inpatients with a primary depressive disorder. Main exclusion criteria were an age older than 62 years and psychotropic drugs other than antidepressants. The psychopathology and other clinical data were routinely assessed within three days after admission by the AMDP documentation. An EEG was also routinely performed at admission. We made use of robust, generally known non-parametric statistics. Those patients who exhibited a dynamically rigid EEG are especially prone to recurrences, have a relative late onset of their illness, and show an acute symptomatology characterized by organic-like features. The findings lend support to our contention that the quantitative assessment of the dynamics of the EEG-Gestalt allows the delimitation of a clinically important subtype that is characterized both cross-sectionally and in long-term respects.

Major depression and the basal ganglia

In the last decade, major changes in our understanding of basal ganglia functions have occurred. Traditionally the basal ganglia were considered to be involved only in the modulation of movement. Recent research has suggested that the basal ganglia also take part in complex fronto-subcortical networks that have an important role in cognition reward, and mood regulation. The authors review recent findings that implicate basal ganglia abnormalities in the pathophysiology of mood disorders and discuss their potential implications for future developments in the pharmacotherapy of depressive disorder.

MRI findings in patients with affective disorder: a meta-analysis

A review of the literature on primarily magnetic resonance imaging (MRI) scans of patients with affective disorders is presented. Several studies have indicated an increased ventricle/brain ratio and other signs of cerebral atrophy, as well as an increased frequency of lesions (so-called signal hyperintensities) in the brains of unipolar and bipolar patients. This notion is strongly supported by two meta-analyses performed in the present study. The lesions are often localized in the frontal lobes and the basal ganglia, indicating a defective basal ganglia/frontal circuit, and are correlated with the degree of cognitive impairment seen in these conditions. No studies have indicated that psychoactive drugs or electroconvulsive therapy (ECT) might cause the lesions, but on the other hand they can probably increase the risk of delirium complicating the treatment.

The functional neuroanatomy of mood disorders

Mood disorders may be associated with global and regional changes in cerebral blood flow and metabolism. The accumulated functional neuroimaging findings in mood disorders were reviewed in order to examine a proposed neuroanatomic model of pathophysiology. Global cerebral blood flow and glucose metabolism appear normal, but may be decreased in late-life depression. Regional cerebral blood flow and glucose metabolism deficits are present, and may be indicators of brain regions participating in neuroanatomic circuits involved in mood disorders. Decreased pre-frontal cortex blood flow and metabolism in depressed unipolar and bipolar patients are the most consistently replicated findings, and correlate with severity of illness. Basal ganglia abnormalities have been found in depressed unipolar and bipolar patients, involving decreased blood flow and metabolism. Temporal lobe abnormalities are present in bipolar disorder patients, and perhaps unipolar depression. There is conflicting evidence of abnormalities in other limbic regions. Cognitive impairment may correlate with decreased metabolism in frontal and cerebellar areas. The relationship between functional neuroimaging findings and clinical course, and therefore state and trait characteristics, has not been systematically investigated. Antidepressant medications, but not ECT, seem to reverse some of the identified functional brain changes in the depressed state. The structural, neurotransmitter and neuropathological correlates of these functional abnormalities are yet to be determined. Functional abnormalities in frontal, subcortical and limbic structures appear to be part of the pathophysiology of mood disorders.

Transcranial magnetic stimulation as therapy for depression and other disorders

OBJECTIVE

To provide an overview of the progress and prospects of transcranial magnetic stimulation as a psychiatric therapy for depression.

METHOD

Published and unpublished studies of the usefulness of transcranial magnetic stimulation as a therapy for depression were assessed, and characterised in terms of a consistent measure of dosage. Additional information was obtained through correspondence, personal meetings and visits to facilities.

RESULTS

Transcranial magnetic stimulation, a means for inducing small regional currents in the brain, has been used in clinical neurology for some time, and can be used on conscious subjects with minimal side-effects. Early researchers noticed transient mood effects on people receiving this treatment, which prompted several inconclusive investigations of its effects on depressed patients. More recently, knowledge of functional abnormalities associated with depression has led to trials using repetitive transcranial magnetic stimulation to stimulate underactive left prefrontal regions, an approach which has produced short-term benefits for some subjects. The higher dosage delivered by high-frequency repetitive transcranial magnetic stimulation appears to produce greater benefits; scope exists for more conclusive studies based on extended treatment periods.

CONCLUSIONS

Repetitive transcranial magnetic stimulation is a promising technology. The reviewed evidence indicates that it may be useful in the treatment of depression, and perhaps other disorders which are associated with regional hypometabolism. Should repetitive transcranial magnetic stimulation prove an effective, non-invasive, drug-free treatment for depression, a range of disorders could be similarly treatable.

Utilising molecular biological and histopathological techniques to study the dopaminergic system in patients with melancholia

OBJECTIVE

To describe the rationale for investigating the dopaminergic system in patients with melancholia by applying molecular biological (notably, in situ hybridisation) and histopathological techniques in postmortem brain tissue.

METHOD

Relevant advances in the functional neuroanatomy of frontostriatal circuits, as well as insights from clinical neuroimaging studies in primary and secondary depressive disorders, are presented. These are integrated with developments in the pharmacological and molecular characteristics of dopamine receptor subtypes and recognition of their selective anatomical distribution.

RESULTS

Converging data from the basic and clinical neurosciences suggest that the pathophysiology of depressive disorders characterised by psychomotor phenomena, such as melancholia, may involve dysregulation of dopaminergic mechanisms within complex frontostriatal circuits.

CONCLUSIONS

The key feature of in situ hybridisation is its capacity to test for variations in the functional components of designated biochemical systems within highly specific anatomical regions. We utilise this approach, in combination with relevant histopathological techniques, to test the structural and functional integrity of the dopaminergic system within key fronto-striatal circuits in patients who had exhibited psychomotor phenomena. The same approach can also be used to study the integrity of other relevant biochemical systems, such as the serotoninergic and noradrenergic systems, in patients with other mood disorders.

The anatomy of mood disorders--review of structural neuroimaging studies

The structural neuroimaging findings in mood disorders were reviewed, to evaluate evidence for a neuroanatomic model of pathophysiology, involving the prefrontal cortex, the basal ganglia, the amygdala-hippocampus complex, thalamus, and connections among these structures. Global atrophy is not consistently found. The best replicated finding is an increased rate of white matter and periventricular hyperintensities. A smaller frontal lobe, cerebellum, caudate, and putamen appear present in unipolar depression. A larger third ventricle, and smaller cerebellum and perhaps temporal lobe appear present in bipolar disorder. These localized structural changes involve regions that may be critical in the pathogenesis of mood disorders. Generalized and localized anatomic alterations may be related to age or vascular disease. The clinical and biological correlates of these changes need to be investigated to allow development of a more complete model of pathophysiology of mood disorders.