a1 Department of Psychiatry, University of Magdeburg, Magdeburg, Germany
a2 Department of Neurology, University of Magdeburg, Magdeburg, Germany
a3 Walter-Friedrich-Krankenhaus Olvenstedt, Magdeburg, Germany
Background The habenular complex is composed of important relay nuclei linking the limbic forebrain to the midbrain and brain stem nuclei. Based on clinical observations, experiments with animals and theoretical considerations, it has been speculated that this brain area might be involved in psychiatric diseases (i.e. schizophrenia and depression). However, evidence in favour of this hypothesis is still lacking because the human habenular complex has rarely been studied with regard to mental illness.
Method We examined habenular volumes in post-mortem brains of 17 schizophrenia patients, 14 patients with depression (six patients with major depression and eight patients with bipolar depression) and 13 matched controls. We further determined the neuronal density, cell number and cell area of the medial habenular nuclei of the same cohorts using a counting box and a computer-assisted instrument.
Results Significantly reduced habenular volumes of the medial and lateral habenula were estimated in depressive patients in comparison to normal controls and schizophrenia patients. We also found a reduction in neuronal cell number and cell area in depressive patients for the right side compared to controls and schizophrenia patients. No such changes were seen in schizophrenia.
Conclusions Our anatomical data argue against prominent structural alterations of the habenular nuclei in schizophrenia but demonstrate robust alterations in depressive patients. We are currently applying immunohistochemical markers to better characterize neuronal subpopulations of this brain region in schizophrenia and depression.
(Received December 10 2008)
(Revised April 28 2009)
(Accepted June 05 2009)
(Online publication August 12 2009)