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Over the past three decades numerous imaging studies have revealed structural and functional brain abnormalities in patients with neuropsychiatric diseases. These structural and functional brain changes are frequently found in multiple, discrete brain areas and may include frontal, temporal, parietal and occipital cortices as well as subcortical brain areas. However, while the structural and functional brain changes in patients are found in anatomically separated areas, these are connected through (long distance) fibers, together forming networks. Thus, instead of representing separate (patho)-physiological entities, these local changes in the brains of patients with psychiatric disorders may in fact represent different parts of the same ‘elephant’, i.e., the (altered) brain network. Recent developments in quantitative analysis of complex networks, based largely on graph theory, have revealed that the brain's structure and functions have features of complex networks. Here we briefly introduce several recent developments in neural network studies relevant for psychiatry, including from the 2013 special issue on Neural Networks in Psychiatry in European Neuropsychopharmacology. We conclude that new insights will be revealed from the neural network approaches to brain imaging in psychiatry that hold the potential to find causes for psychiatric disorders and (preventive) treatments in the future.

Background: Structural brain abnormalities are consistently found in schizophrenia (Sz) and have been associated with the familial risk for the disorder. We aim to define the relative contributions of genetic and nongenetic factors to the association between structural brain abnormalities and Sz in a uniquely powered cohort (Schizophrenia Twins and Relatives consortium). Methods: An international multicenter magnetic resonance imaging collaboration was set up to pool magnetic resonance imaging scans from twin pairs in Utrecht (The Netherlands), Helsinki (Finland), London (United Kingdom), and Jena (Germany). A sample of 684 subjects took part, consisting of monozygotic twins (n = 410, with 51 patients from concordant and 52 from discordant pairs) and dizygotic twins (n = 274, with 39 patients from discordant pairs). The additive genetic, common, and unique environmental contributions to the association between brain volumes and risk for Sz were estimated by structural equation modeling. Results: The heritabilities of most brain volumes were significant and ranged between 52% (temporal cortical gray matter) and 76% (cerebrum). Heritability of cerebral gray matter did not reach significance (34%). Significant phenotypic correlations were found between Sz and reduced volumes of the cerebrum (-.22 [-.30/-.14]) and white matter (-.17 [-.25/-.09]) and increased volume of the third ventricle (.18 [.08/.28]). These were predominantly due to overlapping genetic effects (77%, 94%, and 83%, respectively). Conclusions: Some of the genes that transmit the risk for Sz also influence cerebral (white matter) volume. © 2012 Society of Biological Psychiatry., link_to_OA_fulltext

Schizophrenia patients have more copy number variations (CNVs) than healthy controls, and reduced brain volumes. Although this could suggest a causal relationship, we found no association between global CNV burden and three brain volume measures (on a MRI scan) in a sample of 173 schizophrenia patients and 176 healthy controls.

BackgroundAlthough brain volume changes are found in schizophrenia, only a limited number of structural magnetic resonance imaging studies have exclusively examined antipsychotic-naïve patients.AimsTo comprehensively investigate multiple brain structures in a single sample of patients who were antipsychotic-naïve.MethodTwenty antipsychotic-naïve patients with first-episode schizophrenia and 20 healthy comparison subjects were included. Intracranial, total brain, frontal lobe, grey and white matter, cerebellar, hippocampal, parahippocampal, thalamic, caudate nucleus and lateral and third ventricular volumes were measured. Repeated-measures analyses of (co)variance were conducted with intracranial volume as covariate.ResultsThird ventricle volume enlargement was found in patients compared with the healthy subjects. No differences were found in other brain regions.ConclusionsThese findings suggest that some brain abnormalities are present in the early stages of schizophrenia. Moreover, it suggests that brain abnormalities reported in patients with chronic schizophrenia develop in a later stage of the disease and/or are medication induced.

Neuropsychological studies show impairment in intellectual functions in schizophrenia patients. It is still unclear, however, whether intelligence scores decline progressively during the illness as compared to healthy subjects' scores. Longitudinal studies conducted so far have been restricted to relatively short time spans. The aim of this study is to investigate whether changes in intelligence scores accelerate with age in schizophrenia patients. In a cross-sectional design, performance of four subtests of the Wechsler Adult Intelligence Scale (WAIS) was analyzed in 112 schizophrenia patients and compared to that of 70 healthy subjects, across an age span of 40 years (16-56 years). A linear regression analysis was performed. A main effect on the total ratio score of the four tests was demonstrated between the two groups. No main effect of age and no interaction effect of age with group for the total ratio score were found. The results confirm that there is global intellectual impairment in schizophrenia patients at the onset of illness but no age-accelerated decline and are consistent with the neurodevelopmental hypothesis of schizophrenia.