The Role of Hippocampus in the Pathophysiology of Depression

Hippocampus, as a part of the limbic cortex, has a variety of functions ranging from mating behavior to memory besides its role in the regulation of emotions. The hippocampus has reciprocal interactions of with other brain regions which act in the pathophysiology of major depressive disorder (MDD). Moreover, since the hippocampus is a scene for the neurogenesis, which can be seen as a response to antidepressant treatment, the hippocampus became a focus of attention in neuroimaging studies of MDD. It has been shown that brain derived neurotrophic factor (BDNF), that is responsible from the neurogenesis, is associated with the response to the antidepressants and antidepressant drugs are ineffective if neurogenesis is hindered.Hippocampal atrophy is expected with the decrease of neurogenesis as a result of the lower BDNF levels with the deleterious effects of glucocorticoids in depression. Recurrent and severe depression seems to cause such a volume reduction though first episode MDD subjects do not differ from healthy individuals in respect to their hippocampal volumes (HCVs) measured by magnetic resonance imaging methods. One may argue regarding these findings that the atrophy in the hippocampus may be observed in the long term and the decrease in BDNF levels may predispose the volume reduction. Although it has been postulated that smaller HCV as a result of genetic and environmental factors and prior to the illness, may cause a vulnerability to MDD, sufficient evidence has not been accumulated yet and the view that HCV loss develops as depression progresses is widely accepted. Findings that serum BDNF (sBDNF) is lower in MDD patients though HCVs of patients do not differ from healthy individuals and the positive correlation of sBDNF with HCV seen only in the patient group support this view. It can be assumed that depressed patients have sensitivity for the fluctuations in BDNF levels. Follow-up studies which consider effects of hipotalamo-pituiter-adrenal axis dysregulation and monoamine systems are needed to further elucidate the role of BDNF in the pathogenesis of MDD. Results of these studies may lead the way for the treatment of resistant or recurrent depressive disorder

Sibutramin ile indüklenen bir mikst epizot olgusu

Sibutramine is an antiobesity drug which has also an inbitor effect on NE and 5HT reuptake pumps. These antidepressant pharmacodynamic properties of sibutramine has been proved by pre-clinical and clinical trials. Here, we want to report a 53 years old male patient who did not have any prior hypomanic or manic episodes had a mixed episode after a 3 months of antiobesity treatment by 30 mg/day sibutramine. Since sibutramine has an antidepressant activity drug which may cause affective or psychotic symptoms we wanted to highlight the importance of evaluating the mental and psychiatric status of patients during and prior to treatment.Sibutramin, NE ve 5HT geri alım pompa inhibitörü özelliği olan ve obezite tedavisinde kullanılan bir ilaçtır. Antidepresan özellikteki farmakodinamik etkileri pre-klinik ve klinik çalışmalarla kanıtlanmıştır. Bu yazıda önceden bir manik ya da hipomanik epizod yaşamamış, obezite tedavisi amacıyla 3 ay süreyle 30 mg/ gün dozda sibutramin kullanımı sonrasında mikst epizod ortaya çıkmış 53 yaşındaki bir erkek olgudan söz edilmektedir. Antidepresan etkisi bilinen sibutramin, duygudurum bozuklukluğu ya da psikotik belirtilere neden olabileceğinden sağaltım öncesinde ve sağaltım sürecinde kişinin mental durumunun ve psikiyatrik durumunun değerlendirilmesinin önemi vurgulanmıştır

ARTICLE IN PRESS Th e Disrupted Connection Between Cerebral Hemispheres in Schizophrenia Patients: A Diff usion Tensor Imaging Study •

SUMMARY Aim: In schizophrenia, the disruption of the communication between two brain hemispheres has not been shown clearly in the anatomical aspect despite other studies with different modalities suggested so. In this study, the structural integrity and the variables affecting the structural integrity of the corpus callosum, which is the main connection between two hemispheres, was investigated via diffusion tensor imaging (DTI). Methods: The participants were evaluated by SCID-I and symptoms of the patients were assessed with PANSS. DT images of 25 schizophrenia patients and 17 healthy volunteers were acquired via 1.5 T MR. Fractioned Anisotropy (FA) values of two groups, measured on the DT images, were compared. Results: It was found that fractioned anisotropy (FA) values were lower in the genu of the patients than the healthy controls; however, there was no difference between the FA values of the patients and the controls in the splenium. Moreover, a significant negative correlation between the splenium FA values and the antipsychotic medication doses; and a trend level negative correlation of splenium FA and PANSS scores were found. Conclusion: Corpus callosum is the most important structure that connects two frontal lobes. The hypothesis that posits the fundamental role of the disconnection of frontal lobes in schizophrenia is supported by the findings of this study