Regional brain volumes, diffusivity, and metabolite changes after electroconvulsive therapy for severe depression.

OBJECTIVE: To investigate the role of hippocampal plasticity in the antidepressant effect of electroconvulsive therapy (ECT). METHOD: We used magnetic resonance (MR) imaging including diffusion tensor imaging (DTI) and proton MR spectroscopy (1 H-MRS) to investigate hippocampal volume, diffusivity, and metabolite changes in 19 patients receiving ECT for severe depression. Other regions of interest included the amygdala, dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex, and hypothalamus. Patients received a 3T MR scan before ECT (TP1), 1 week (TP2), and 4 weeks (TP3) after ECT. RESULTS: Hippocampal and amygdala volume increased significantly at TP2 and continued to be increased at TP3. DLPFC exhibited a transient volume reduction at TP2. DTI revealed a reduced anisotropy and diffusivity of the hippocampus at TP2. We found no significant post-ECT changes in brain metabolite concentrations, and we were unable to identify a spectral signature at ≈1.30 ppm previously suggested to reflect neurogenesis induced by ECT. None of the brain imaging measures correlated to the clinical response. CONCLUSION: Our findings show that ECT causes a remodeling of brain structures involved in affective regulation, but due to their lack of correlation with the antidepressant effect, this remodeling does not appear to be directly underlying the antidepressant action of ECT.

An intron 1 polymorphism in the cholecystokinin-A receptor gene associated with schizophrenia in males.

OBJECTIVE: To identify whether a genetic variation (rs1800857; IVS1-5T>C) in the neuropeptide cholecystokinin-A receptor (CCKAR) gene is a risk factor in the pathogenesis of schizophrenia. METHOD: The variation was analysed in a case-control design comprising 508 patients with schizophrenia and 1619 control subjects. A possible functional impact of this variant on CCKAR protein synthesis through alterations in splicing was analysed in an exon-trapping assay. RESULTS: In males only, the risk variant, IVS1-5C, was associated with a significantly increased risk of schizophrenia. Carrying one risk allele was associated with an increased risk of 1.74 (Odds Ratio, OR) and homozygosity (CC) was associated with an OR of 3.19. The variation had no impact on protein synthesis of CCKAR. CONCLUSION: This is the first report associating the CCKAR gene variant with schizophrenia specifically in men. Our study strengthens the conclusion that a CCKAR dysfunction could be involved in the aetiology of schizophrenia.

Electrophysiological subtypes of psychotic states.

OBJECTIVE: This research sought neurobiological features common to psychotic states displayed by patients with different clinical diagnoses. METHOD: Cluster analysis with quantitative electroencephalographic (QEEG) variables was used to subtype drug-naïve, non-medicated, and medicated schizophrenic, depressed and alcoholic patients with psychotic symptoms, from the USA and Germany. QEEG source localization brain images were computed for each cluster. RESULTS: Psychotic patients with schizophrenia, depression and alcoholism, and drug- naïve schizophrenic patients, were distributed among six clusters. QEEG images revealed one set of brain regions differentially upregulated in each cluster and another group of structures downregulated in the same way in every cluster. CONCLUSION: Subtypes previously found among 94 schizophrenic patients were replicated in a sample of 390 non-schizophrenic as well as schizophrenic psychotics, and displayed common neurobiological abnormalities. Collaborative longitudinal studies using these economical methods might improve differential understanding and treatment of patients based upon these features rather than clinical symptoms.

Reduced midbrain-pons serotonin transporter binding in patients with obsessive-compulsive disorder.

OBJECTIVE: To evaluate current hypothesis regarding the pathophysiology of obsessive-compulsive disorder (OCD) by studying the serotonin receptor binding in patients with OCD using single photon emission computerized tomography (SPECT). METHOD: We studied nine patients (four men and five women, age range 21-56 years) fulfilling the DMS-III-R criteria for OCD using SPECT and the serotonin transporter (SERT) tracer (123)I-beta-CIT. SERT binding potential (BP2) was determined by Logan plot derived from seven scans obtained during 10-400 min. RESULTS: The binding of (123)I-beta-CIT in midbrain-pons was reduced in OCD patients when compared with controls (BP2 0.97 +/- 0.07 vs. 0.84 +/- 0.12, P = 0.011). There was no correlation between BP2 and any of the clinical variables (age at onset, disease duration, and Yale-Brown Obsessive-Compulsive Scale score). CONCLUSION: This study suggests a reduced serotonergic input into the fronto-subcortical circuits in OCD, thereby diminishing the inhibitory regulation of serotonin on these circuits.

Toward a better understanding of the pathophysiology of OCD SSRI responders: QEEG source localization.

OBJECTIVE: To demonstrate the utility of three-dimensional source localization of the scalp-recorded electroencephalogram (EEG) for the identification of the most probable underlying brain dysfunction in patients with obsessive-compulsive disorder (OCD). METHOD: Eyes-closed resting EEG data was recorded from the scalp locations of the International 10/20 System. Variable resolution electromagnetic tomography (VARETA) was applied to artifact-free EEG data. This mathematical algorithm estimates the source generators of EEG recorded from the scalp. RESULTS: An excess in the alpha range was found with sources in the corpus striatum, in the orbito-frontal and temporo-frontal regions in untreated OCD patients. This abnormality was seen to decrease following successful treatment with paroxetine. CONCLUSION: The VARETA findings of an activation/deactivation pattern in cortical and subcortical structures in paroxetine-responsive patients are in good accordance with data obtained in previously published positron emission tomography studies related to current hypotheses of a thalamo-striatal-frontal feedback loop being relevant for understanding the pathophysiology of OCD.

Electroconvulsive therapy in melancholia: the role of hippocampal neurogenesis.

OBJECTIVE: To elucidate the relationship between the effects of electroconvulsive therapy (ECT) on hippocampal anatomy and function in the therapy of melancholic depression and preclinical observations of increased neurogenesis in the hippocampus of experimental animals receiving electroconvulsive seizures (ECS). We emphasize the role of hypercortisolaemia in melancholic depression and in experimental hippocampal neurogenesis. METHOD: Our statements are based on a variety of studies pointing to i) ECT being superior to all other treatment modalities in the therapy of melancholia, ii) melancholia being associated with hypercortisolaemia and iii) evidence of hippocampal neurogenesis being relevant for understanding both melancholia and ECT. RESULTS: The increased neurogenesis found in animal studies shows stronger effect of seizures than of antidepressant drugs. The onset of effect is not only faster but is also sustained. Newborn cells are found to be functional. Suppression of neurogenesis by chronic treatment with corticosterone is associated with depression-like biology and behaviour making comparison with human depression and its response to ECT relevant. CONCLUSION: We hypothesize that the superior antimelancholic effect of induced seizures may be understood in the light of the powerful control of neural plasticity exerted by the regulation of the hypothalamic-pituitary-adrenal axis and, perhaps, other regulatory factors.

No association between the -399 C > T polymorphism of the neuropeptide Y gene and schizophrenia, unipolar depression or panic disorder in a Danish population.

OBJECTIVE: A polymorphism in the promoter region of the NPY gene at position -399 C > T was recently reported to be associated with schizophrenia in a Japanese population and with treatment refractory unipolar depression in a Swedish population. The objective of this study was to investigate potential associations between the polymorphism and three psychiatric disorders in a Danish population. METHOD: We investigated the occurrence of the polymorphism in patients with schizophrenia (n = 291), unipolar depression (n = 256) and panic disorder (n = 142) compared with controls (n = 716). RESULTS: We detected the polymorphism -399 C > T at a frequency of 48% in controls. No significant differences were found between genotype or allele frequencies in controls vs. the patient groups. CONCLUSION: The lack of association between the -399 C > T polymorphism and schizophrenia, unipolar depression or panic disorder, respectively, suggests that the polymorphism is not involved in the etiology of these disorders in the Danish population.

Levetiracetam prevents changes in levels of brain-derived neurotrophic factor and neuropeptide Y mRNA and of Y1- and Y5-like receptors in the hippocampus of rats undergoing amygdala kindling: implications for antiepileptogenic and mood-stabilizing properties.

The amygdala-kindling model has been proposed as a model of sensitization processes with relevance to epilepsy as well as affective disorders. Levetiracetam is a novel anticonvulsant drug that delays the process of kindling, i.e., possesses antiepileptogenic properties. Preliminary reports also suggest a mood-stabilizing potential for levetiracetam. Brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY) are central modulators of seizure activity, which undergo plastic changes during kindling epileptogenesis. Consequently, we investigated the regulation of BDNF and NPY mRNA and Y1-, Y2-, and Y5-like receptor binding in the hippocampus of vehicle-pretreated, partially and fully amygdala-kindled rats and corresponding levetiracetam-pretreated rats (40 mg/kg i.p.). The present data indicate that the process of kindling is associated with an upregulation of hippocampal BDNF and NPY mRNA levels and downregulation of Y1- and particularly Y5-like receptors. Pretreatment with levetiracetam markedly delays the progression of kindling and, in addition, exhibits a clear anticonvulsant effect. These effects are associated with abolition of the kindling-induced rise in BDNF and NPY mRNA and increasing levels of Y1- and particularly Y5-like receptors in all hippocampal subfields. Lastly, the present study reveals that an identical dose of levetiracetam reduced immobility in the rat forced swim test, the first experimental evidence indicative of an antidepressant and/or mood stabilizer-like profile of this drug. Considering that animal depression models display impairments in hippocampal NPY systems that become normalized following mood-stabilizing treatment, and that exogenous NPY exerts anticonvulsant as well as antidepressive-like activity in rodents, it is a heuristic possibility that increased hippocampal excitability and affective symptomatology may converge on an impaired hippocampal NPY function. Speculatively, the ability of levetiracetam to increase hippocampal Y1- and Y5-like receptor levels may have implications for the antiepileptic properties of levetiracetam, as well as its purported mood-stabilizing properties.

Arrested neuronal proliferation and impaired hippocampal function following fractionated brain irradiation in the adult rat.

The generation of new neurons in the adult mammalian brain has been documented in numerous recent reports. Studies undertaken so far indicate that adult hippocampal neurogenesis is related in a number of ways to hippocampal function.Here, we report that subjecting adult rats to fractionated brain irradiation blocked the formation of new neurons in the dentate gyrus of the hippocampus. At different time points after the termination of the irradiation procedure, the animals were tested in two tests of short-term memory that differ with respect to their dependence on hippocampal function. Eight and 21 days after irradiation, the animals with blocked neurogenesis performed poorer than controls in a hippocampus-dependent place-recognition task, indicating that the presence of newly generated neurons may be necessary for the normal function of this brain area. The animals were never impaired in a hippocampus-independent object-recognition task. These results are in line with other reports documenting the functional significance of newly generated neurons in this region. As our irradiation procedure models prophylactic cranial irradiation used in the treatment of different cancers, we suggest that blocked neurogenesis contributes to the reported deleterious side effects of this treatment, consisting of memory impairment, dysphoria and lethargy.

Affective disorders in neurological diseases: a case register-based study.

OBJECTIVE: To investigate the temporal relationships between a range of neurological diseases and affective disorders. METHOD: Data derived from linkage of the Danish Psychiatric Central Register and the Danish National Hospital Register. Seven cohorts with neurological index diagnoses and two control group diagnoses were followed for up to 21 years. The incidences of affective disorders in the different groups were compared with the control groups, using competing risks to consider the risk of affective disorder and the risk of death in the same analysis. RESULTS: We found an increased incidence of affective disorders in dementia, Parkinson's disease, epilepsy, stroke and intracerebral haemorrhage compared with control groups. The association was found to be the strongest for dementia and Parkinson's disease. In hospitalized patients, with incident multiple sclerosis, the incidence of affective disorder was lower than the incidence in the control groups. CONCLUSION: In neurological diseases there seems to be an increased incidence of affective disorders. The elevated incidence was found to be particularly high for dementia and Parkinson's disease (neurodegenerative diseases).

Neuropeptide Y inhibits in vitro epileptiform activity in the entorhinal cortex of mice.

Previous studies show that neuropeptide Y (NPY) inhibits in vitro seizures in rodent hippocampus. Here, we explored the effect of NPY application on epileptiform discharges induced by perfusion with magnesium-free solution in slices of entorhinal cortex from two different mouse strains. NPY significantly reduced the duration of epileptiform discharges with a peak effect of 36-50%. This is the first study showing anti-epileptiform effect of NPY in the entorhinal cortex and also the first evidence that NPY inhibits seizures in a cortical region in mice. The entorhinal cortex has a central role in transferring information between the hippocampus and the rest of the brain. Therefore our data further strengthen the concept of NPY and its receptors as widespread regulators of epileptiform activity and as a potential future target for antiepileptic therapy.

Enduring increased risk of developing depression and mania in patients with dementia.

OBJECTIVE: To investigate the time relation between dementia and major affective disorders (major depression and mania). METHODS: Register linkage study of the Danish Hospital Register and the Danish Psychiatric Central Research Register, to establish study cohorts of patients with dementia and control groups (osteoarthritis or diabetes) on first discharge from hospital. Follow up of cohorts was for up to 21 years. Hazard of death was allowed for by the use of competing risks models. RESULTS: Patients with dementia had an increased risk of being admitted to hospital for major depression or mania during the course of the illness. The incidence remained elevated throughout the rest of the patient's life. CONCLUSIONS: Patients with dementia have an increased risk of developing depression or mania. Proper treatment of affective disorders in patients with dementia is important in reducing suffering and costs.

Early maternal deprivation alters hippocampal levels of neuropeptide Y and calcitonin-gene related peptide in adult rats.

Stressful events early in life are reported to be more prevalent among patients with an adult life psychiatric disorder. Early maternal deprivation is considered an animal model of early life stress. Maternally deprived adult rats display long-term alterations in the neuroendocrine system, brain and behavior that are in many ways analogous to depressive and schizophrenic symptomatology. Neuropeptide Y (NPY) and calcitonin-gene related peptide (CGRP) have been implicated in both disorders and also been suggested to play a role in the neuroadaptational response to stress. Consequently, male Wistar rat-pups were subjected to early maternal deprivation or control handling, on postnatal day (pnd) 9. On pnd 21, pups were weaned and split into two groups that were reared either on a saw-dust floor or on a grid-floor, considered to be a mild stressor. On pnd 67, all animals were subjected to the prepulse inhibition test. One week later, the animals were sacrificed, the brains removed and dissected on ice. Levels of NPY-like immunoreactivity (LI) and CGRP-LI were quantified by radioimmunoassay in brain regional extracts. Maternal deprivation led to a significant reduction in basal startle amplitude and disruption of prepulse inhibition. These findings were paralleled by significantly reduced levels of NPY and CGRP in the hippocampus and occipital cortex. It is hypothesised that these changes may be of relevance to aspects of schizophrenic and affective symptomatology. The present study further shows that brain NPY and, in particular, CGRP are sensitive to long-term mild stress and further implicate the involvement of these peptides in the neuroendocrine stress response.

Increased risk of developing Parkinson's disease for patients with major affective disorder: a register study.

OBJECTIVE: To investigate whether patients with a diagnosis of affective disorder are at an increased risk of developing Parkinson's disease compared with medically ill control groups. METHOD: By linkage of public hospital registers from 1977 to 1993, three study cohorts were identified: patients with affective disorder episodes (mania or depression) and patients with osteoarthritis or diabetes. Time to the first diagnosis of Parkinson's disease was estimated with the use of survival analysis. RESULTS: A total of 164 385 patients entered the study base. The risk of being given a diagnosis of Parkinson's disease was significantly increased for patients with affective disorder, odds ratio 2.2 (CI 95% 1.7-2.8) compared with osteoarthritis, and depressive disorders, odds ratio 2.2 (CI 95% 1.7-2.9) compared with osteoarthritis. CONCLUSION: This study supports the hypothesis of a common aetiology for major affective disorder and Parkinson's disease.

Increased neurogenesis in a model of electroconvulsive therapy.

BACKGROUND: Electroconvulsive therapy (ECT) is a widely used and efficient treatment modality in psychiatry, although the basis for its therapeutic effect is still unknown. Past research has shown seizure activity to be a regulator of neurogenesis in the adult brain. This study examines the effect of a single and multiple electroconvulsive seizures on neurogenesis in the rat dentate gyrus. METHODS: Rats were given either a single or a series of 10 electroconvulsive seizures. At different times after the seizures, a marker of proliferating cells, Bromodeoxyuridine (BrdU), was administered to the animals. Subsequently, newborn cells positive for BrdU were counted in the dentate gyrus. Double staining with a neuron-specific marker indicated that the newborn cells displayed a neuronal phenotype. RESULTS: A single electroconvulsive seizure significantly increased the number of new born cells in the dentate gyrus. These cells survived for at least 3 months. A series of seizures further increased neurogenesis, indicating a dose-dependent mechanism. CONCLUSIONS: We propose that generation of new neurons in the hippocampus may be an important neurobiologic element underlying the clinical effects of electroconvulsive seizures.

Electroconvulsive stimuli enhance both neuropeptide Y receptor Y1 and Y2 messenger RNA expression and levels of binding in the rat hippocampus.

Repeated electroconvulsive stimulations and other seizure modalities produce an increase in neuropeptide Y synthesis and local release in the rat hippocampus, and perhaps as a consequence, a change in the concentration of neuropeptide Y binding sites in the same region. The aim of the present study was to determine possible changes in the expression of neuropeptide Y receptor subtypes affected by repeated stimulations in the hippocampus. Rats were exposed to 14 daily stimulations, and the brains were removed 24h after the last stimulation. For in vitro receptor autoradiography and in situ hybridisation histochemistry, the brains were frozen, sectioned, and levels of neuropeptide Y binding sites and messenger RNA expressions were determined quantitatively on sections from the same animals. In order to determine the contribution of different neuropeptide Y receptor subtypes, serial sections were incubated with either 125I-labelled peptide YY alone or the same radio-labelled peptide mixed with an excess of a number of displacing compounds with affinity for either neuropeptide Y receptor subtype Y1, Y2, or both. Binding studies revealed that the majority of peptide YY binding sites was represented by Y2, and that electroconvulsive stimulations reduced the binding capacity or the concentration of this receptor. A prominent reduction of Y1-preferring binding sites was determined in the dentate gyrus, and to a lesser extent in the CA1 and CA3 regions. Similarly, the treatment produced a significant reduction of Y2-preferring binding sites in the CA1 and CA3 region, but not in the granular cell layer of the dentate gyrus. Using semi-quantitative in situ hybridization, Y1 receptor messenger RNA level in the granular cell layer of the dentate increased by the stimulations. In the same region, Y2 receptor messenger RNA was expressed in low to undetectable amounts, but after the repeated stimulations, this transcript was found in moderate to high levels. These data suggest that the neuropeptide Yergic system in the dentate gyrus and the pyramidal cell layer are affected by the treatment, and that this includes both Y1 and Y2 receptor subtypes. Because levels of messenger RNA and binding are distinctly regulated, the turnover of both Y1 and Y2 molecules is strongly increased under electroconvulsive stimulations, suggesting that the intrahippocampal neuropeptide Yergic neurotransmission is also increased under the stimulations.