What is asserted with evidence cannot be dismissed without evidence : modelos explicativos baseados em evidências para a neurocognição nos transtornos bipolares

Abstract

This doctoral thesis deals with the intersection of cognitive neuropsychology, clinical psychology and the psychopathology of bipolar disorder (BD). This thesis, titled “What is asserted with evidence cannot be dismissed without evidence: Modelos explicativos baseados em evidências para a neurocognição nos transtornos bipolares”, comprises four empirical studies of the association between of executive and mnemonic abilities to clinical, sociodemographic, functional and cognitive reserve variables in BDI and BDII. The first study, “Bipolar disorder psychopathology and neuropsychology: a state-of-the-art meta-analysis of executive functions and episodic memory”, involved a meta-analysis and meta-regression of 126 studies with a total of 14402 participants. Results revealed widespread cognitive impairments in BDI, with moderate to large effect sizes. Patients with BDII performed worse than control subjects with small-to-medium effect sizes for executive functions (EF) and memory. Small but significant differences were also identified between BDI and BDII on all cognitive functions except inhibitory control. Moderator analyses highlighted the role of education, (hypo)manic symptoms and lithium use in cognitive impairment in BD. The second empirical study, “The predictive role of daily cognitive stimulation on executive functions in bipolar disorder”, involved linear regression models of working memory, inhibitory control and cognitive flexibility. Stepwise hierarchical regression models revealed that the frequency of reading and writing, IQ and diagnosis predicted 38.1% of the variance in inhibition. Diagnosis and IQ predicted 24.9% of the variance in working memory scores. Cognitive flexibility was predicted by reading and writing only, which accounted for 7.6% of the variance in this construct. The third empirical study, “Modelo Preditivo de Funções Executivas por Equação Estrutural no Transtorno Bipolar: o papel da reserva cognitiva e de variáveis clínicas e demográficas para a neurocognição” involved the construction of structural equation models to predict the following latent executive abilities: working memory, verbal fluency, inhibitory control and cognitive flexibility. The most significant predictors of executive performance in these models were age, diagnosis, depressive symptoms and cognitive reserve. The later also mediated the effects of age, diagnosis, depressive symptoms and history of suicide attempts on the EF. Lastly, the fourth study, “Modelo preditivo de funcionalidade por equação estrutural no transtorno bipolar: contribuições de variáveis clínicas, demográficas, neurocognitivas e de reserva cognitiva”, involved a similar statistical approach to study 3, but focused on the predictors and mediators of functioning in BDI, BDII and control subjects. Two main facets of functioning were identified in the study, and referred to as instrumental and interpersonal functioning, respectively. Both were negatively influenced by depressive symptoms, and positively influenced by cognitive reserve. Interpersonal functioning suffered a negative effect of BDI and history of substance use disdorers. Instrumental functioning also suffered a negative influence of a diagnosis of BD. These models contributed to the identification of predictors, moderators and mediators of functioning and cognition in BD, contributing to the development of evidence-based treatments and interventions.