Focusing on Comorbidity A Novel Meta-Analytic Approach and Protocol to Disentangle the Specific Neuroanatomy of Co-occurring Mental Disorders

Background: In mental health, comorbidities are the norm rather than the exception. However, current meta-analytic methods for summarizing the neural correlates of mental disorders do not consider comorbidities, reducing them to a source of noise and bias rather than benefitting from their valuable information. Objectives: We describe and validate a novel neuroimaging meta-analytic approach that focuses on comorbidities. In addition, we present the protocol for a meta-analysis of all major mental disorders and their comorbidities. Methods: The novel approach consists of a modification of Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) in which the linear models have no intercept. As in previous SDM meta-analyses, the dependent variable is the brain anatomical difference between patients and controls in a voxel. However, there is no primary disorder, and the independent variables are the percentages of patients with each disorder and each pair of potentially comorbid disorders. We use simulations to validate and provide an example of this novel approach, which correctly disentangled the abnormalities associated with each disorder and comorbidity. We then describe a protocol for conducting the new meta-analysis of all major mental disorders and their comorbidities. Specifically, we will include all voxel-based morphometry (VBM) studies of mental disorders for which a meta-analysis has already been published, including at least 10 studies. We will use the novel approach to analyze all included studies in two separate single linear models, one for children/adolescents and one for adults. Discussion: The novel approach is a valid method to focus on comorbidities. The meta-analysis will yield a comprehensive atlas of the neuroanatomy of all major mental disorders and their comorbidities, which we hope might help develop potential diagnostic and therapeutic tools

Une méta-analyse de l’efficacité des thérapies cognitivo-comportementales dans le traitement de la dépression chez les personnes âgées

A comprehensive meta-analysis was conducted using studies of cognitive-behavioural-therapy based interventions (CBT-BIs) for late-life depression. Patient characteristics, CBT modality, and other study variables were analyzed using subgroup and metaregression analysis methods. Results showed the collective treatment effect of CBT-BIs for reducing late-life depression to be moderate (g = -0.63) with significant heterogeneity (I2 = 66.12%). CBT-BIs were found to be no more effective immediately posttreatment than other psychological treatments, pharmacotherapy, or combination interventions. The data support the notion that CBT is more effective in the long term.On a mené une méta-analyse approfondie d’après des interventions basées sur la thérapie cognitivo-comportementale (IB-TCC) conçues pour le traitement de la dépression à un âge avancé. On analysa les caractéristiques du patient, les modalités de la TCC et d’autres variables de l’étude, en ayant recours à des méthodes d’analyse de sous-groupe et d’analyse de métarégression. Les résultats ont révélé que l’effet du traitement collectif des IB-TCC en vue d’atténuer la dépression en âge avancé était moyen (g = -0,63) et considérablement hétérogène (I2 = 66,12 %). On a conclu que les IB-TCC ne se révélaient pas plus efficaces immédiatement après le traitement que les autres types de traitements psychologiques, pharmacothérapeutiques ou que les interventions combinées. Les données semblent indiquer que la TCC est plus efficace à long terme

Neuropsychological comparisons of cocaine versus methamphetamine users: A research synthesis and meta-analysis

<p><i>Background</i>: Previous meta-analytical research examining cocaine and methamphetamine separately suggests potentially different neuropsychological profiles associated with each drug. In addition, neuroimaging studies point to distinct structural changes that might underlie differences in neuropsychological functioning. <i>Objectives</i>: This meta-analysis compared the effect sizes identified in cocaine versus methamphetamine studies across 15 neuropsychological domains. <i>Method</i>: Investigators searched and coded the literature examining the neuropsychological deficits associated with a history of either cocaine or methamphetamine use. A total of 54 cocaine and 41 methamphetamine studies were selected, yielding sample sizes of 1,718 and 1,297, respectively. Moderator analyses were conducted to compare the two drugs across each cognitive domain. <i>Results</i>: Data revealed significant differences between the two drugs. Specifically, studies of cocaine showed significantly larger effect-size estimates (i.e., poorer performance) in verbal working memory when compared to methamphetamine. Further, when compared to cocaine, methamphetamine studies demonstrated significantly larger effect sizes in delayed contextual verbal memory and delayed visual memory. <i>Conclusion</i>: Overall, cocaine and methamphetamine users share similar neuropsychological profiles. However, cocaine appears to be more associated with working memory impairments, which are typically frontally mediated, while methamphetamine appears to be more associated with memory impairments that are linked with temporal and parietal lobe dysfunction.</p