Regional cerebral blood flow and lateralized hemispheric dysfunction in depression

Disappearance of hypothalamic TRH asymmetry in suicide patients

The aim of the present study was to investigate the functional and/or pathological significance of the hemispherical lateralization of TRH using radioimmunoassay to determine the TRH concentration of nuclei and areas within the hypothalamus of suicide patients, with matching measurement being carried out on control subjects. In suicide patients, we found no significant difference in TRH concentration between the left and right intrahypothalamic structures, while the group used as control subjects (see Borson-Chazot, 1986) showed a significant left side predominance in the ventromedial nucleus, paraventricular nucleus and area dorsalis. As regards the TRH concentration in the right intrahypothalamic structures, no significant difference was found between the suicide patients and the control subjects. The absence of the left TRH predominance for the three intra-hypothalamic structures in question may be of pathological significance.

Biological studies of dysthymia

Dysthymic disorder (DD) is a chronic subsyndromal depressive condition that has generated increasing interest since its formal introduction into the psychiatric nomenclature in 1980. Although DD was included among the affective disorders in DSM-III, this classification was controversial. Some clinical and family studies support an association between DD and major depression disorder (MDD), but there has been little additional research firmly establishing the diagnostic validity of DD or clarifying its relation to MDD and to personality disorders. In this article, the literature on the biology of DD is reviewed. Studies of rapid eye movement (REM) latency, electrodermal activity, and the thyroid axis show similarities between DD and MDD, but the findings are mixed. Other investigations, including the Dexamethasone Suppression Test (DST), catecholamines, and several other electroencephalogram (EEG) sleep variables, show more consistent differences between DD and MDD. These findings suggest that DD manifests primarily trait characteristics of depression, thus differentiating it from the state characteristics of MDD. The methodological problems and implications of these studies, and suggestions for future research, are discussed.

Regional cerebral blood flow in patients with affective disorders

Regional cerebral blood flow at rest was measured in 38 patients with major depressive disorders and 16 controls by SPECT with inhalation of xenon-133. All subjects had been withdrawn from medication. The mean hemispheric cerebral blood flow was not statistically different between the controls and the different subgroups of depressed patients defined either by biological markers or clinical characteristics. However, the predominantly cortical blood flow, measured on the outer cerebral rim of the third tomographic slice, was significantly lower on the left hemisphere in bipolar patients when compared with normals and unipolar patients. The same lateralisation was observed in patients with an endogenous depression according to the Newcastle scale.

Regional cerebral blood flow in depression

Regional cerebral blood flow (rCBF) was measured in patients with endogenous depression by the single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I]iodoamphetamine (IMP). The subjects were 32 patients with endogenous depression and 20 normal controls. These 32 patients, who were divided into 10 unmedicated group and 22 medicated group, were reexamined when the depressed patients reverted to a euthymic state (remission). The value of rCBF was assessed by the corticocerebellar ratio (CCR), which was expressed as a ratio of activity per pixel in the cerebral regions of interests (ROIs) to the activity per pixel in the cerebellum. The depressive patients showed a decrease in rCBF all over the cerebral regions and, especially, the lower rCBF in the left than in the right hemisphere. These changes turned toward normal in a remitted state following treatments, though there was no significant difference in rCBF between the medicated and unmedicated patients. There was a significantly negative correlation between the severity of depressive symptoms and the mean rCBF in a total of patients with depression. These results suggest that psychiatric symptoms in the depressive patients might be related to the left hemispheric dysfunction.

Affect, affective disorder and schizophrenia. A neuropsychological investigation of right hemisphere function

Performance on a happy-sad chimeric face test was used to examine the role of right hemisphere activation in positive and negative affect, both normal and abnormal, as well as in schizophrenia. This test is known to elicit a left-sided perceptual bias in right-handed normal subjects. Happy and sad mood in normals did not influence the perceptual bias. Depression and mania were associated with reduced and increased biases respectively, while schizophrenics showed no bias to either side. Possible explanations are right hemisphere hyperfunction in mania, moderate relative hypofunction in depression, and severe relative hypofunction in schizophrenia. The marked difference between mania and schizophrenia supports distinct pathophysiologies underlying the two conditions.

Regional cerebral blood flow in depression: associations with psychopathology

Regional cerebral blood flow (rCBF) was measured during rest and cognitive activation in 21 patients with a major depressive episode and 21 healthy subjects. Depressive patients had significantly lower rCBF during rest in the right global, frontal, parietal, occipital and temporal regions and in the left global and frontal regions. During mental activation patients showed significantly lower values in all right and left parietal regions. rCBF was correlated with the scores of the Brief Psychiatric Rating Scale (BPRS), the parietal regions. rCBF was correlated with the scores of the Brief Psychiatric Rating Scale (BPRS), the Bech-Rafaelsen Melancholia Scale (BRMS), the Hamilton Depression Scale (HAM-D) and the Hamilton Anxiety Scale (HAM-A). The most significant negative correlations were obtained with the BPRS. Correlation analyses between each single item of the BPRS and CBF values revealed the strongest associations between emotional withdrawal and decreased CBF. Patients with 'reactive' features had higher CBF than patients without 'reactive' symptoms. Only patients without 'reactive' symptoms had a lower CBF than controls. 'Endogenous' features had no impact on CBF.

Neuroanatomical studies of major affective disorders. A review and suggestions for further research

Interest in the long-neglected neuropathology of major affective disorders has recently been rekindled, partly because of the emergence of brain-imaging techniques. We review the literature suggesting that attention be given to the neuroanatomy and neuropathology of primary and secondary affective disorders. Computerised tomography studies show that patients with affective disorders tend to be similar to schizophrenic patients and significantly different from normal control subjects in ventricle:brain ratio, sulcal widening, and cerebellar vermian atrophy. As yet, there are few neuropathological investigations of the brains of patients with primary affective disorders. Suggestions for further research in the neuropathology of affective disorders are offered.

Exercise and mental health

This paper reviews the mood altering properties of exercise and its potential in the prevention and treatment of mental disorders. The role of the brain monoamines, opioid peptides, the sympathetic nervous system, and cognitive behavioural theory as mediating pathways for the psychological benefits of exercise is critically examined. Clinical trials on exercise are reviewed and suggestions are made for future research in this field.

Pathological cerebral blood flow during motor function in schizophrenic and endogenous depressed patients

In this investigation we examined eight Type I (positive symptoms without marked negative symptomatology), eight Type II (marked negative symptoms) schizophrenic patients of the disordered and paranoid diagnostic subgroups (DSM-III 295.1 and 295.3), eight severely (HAMD above 35) and eight less severely (HAMD below 20) endogenous depressed patients, and eight control persons using the 133Xe inhalation method in resting condition and during motor activity of the dominant right hand. In all patient groups we found flow activation patterns that were different from those observed in normal control persons. During motor activation in Type I schizophrenics and in less severely endogenous depressed patients, we found a bilateral hyperflow and a diffuse cortical flow increase, also involving deeper cerebral structures. In Type II schizophrenics and severely endogenous depressed patients, however, we found a widespread nonreactivity of the regional cerebral blood flow (rCBF) to motor activation, with no flow increase in the contralateral primary motor area. In normal control individuals, we reproduced a 25% flow increase that was strictly limited to the contralateral primary motor area, as already reported by other authors. As only the schizophrenic patients were not under antipsychotic medication (4 with a washout of at least 1 week prior to the investigation, 12 never treated with drugs before), contaminating effects of the medication cannot be ruled out for the endogenous depressed patient groups. However, in schizophrenic patients, these results suggest a diffuse disorganization and lack of laterality of motor functional systems. In addition, the change from hyperactivity to hyporeactivity might indicate cerebral functional correlates of the change from Type I to Type II symptomatology in schizophrenic patients, which could possible prove to be of clinical importance.

Images of the brain in psychiatry

In psychiatry, the use of computer-based techniques for constructing images of the brain is relatively recent. Nevertheless, findings that have resulted from their use thus far might provide us with a new perspective in the understanding of mental illness. They raise the possibility that many of the disorders, previously understood primarily in terms of psychosocial factors, are associated with specific abnormalities of brain structure and/or function. Although terms such as NMR, BEAM, RCBF, SPECT and PET are increasingly found in medical and psychiatric journals, few people understand in simple terms the principles on which these techniques are based. In this article the techniques used for constructing images of brain structure and function are explained, and an overview of the findings in psychiatric disorders is presented.

Criteria for diagnosing reversible dementia caused by depression: validation by 2-year follow-up

Eighteen patients fulfilling DSM-III criteria for both major depression and dementia were matched by age and sex to patients with a diagnosis of irreversible dementia and patients with a diagnosis of major depression. A past history of depression, self reports of depressed mood, self blaming, hopeless and somatic delusions, an appetite disturbance and subacute onset identified the patients suffering from dementia caused by depression. Two year follow-up confirmed the initial diagnosis and demonstrated that coexisting cognitive impairment and major depression are not usually precursory to a progressive dementing illness.