Schizophrenia (SCZ) and bipolar disorder (BD) are regarded as severe mental disorders, with chronic course and large socio-familiar and functional burden (Charlson et al., 2018; Ferrari et al., 2016; Whiteford et al., 2013). Whistle the classical presentation of SCZ comprises delusions, hallucinations, emotional withdrawal, and flattened affect, the clinical picture of BD usually comprises mood shifts (mania and depression), increased or loss of energy, and speed thought disturbances (Charlson et al., 2018; Phillips and Kupfer, 2013). Many studies reported functional network disturbances in both SCZ and BD (Dezhina et al., 2019; Meda et al., 2016; Öngür et al., 2010; Tamminga et al., 2014). For instance, the underlying functional network of both SCZ and BD exhibited altered activation in several brain areas, e.g., the prefrontal cortex (PFC), hippocampus (HC), medial temporal cortex (MTL), and the parahippocampal and fusiform gyrus; functional disturbances in other cerebral structures, such as the cerebellum and thalamus, were also found among SCZ subjects (Andreasen et al., 1995; Cabeza et al., 1997; Desgranges et al., 1998; Sperling et al., 2001).

While great effort has been pursued to characterize the neuroimaging underpinnings of SCZ and BD, a much less explored topic is the role of ethnicity in the brain connectivity of psychotic and mood disorders. Very few studies have emphasized this topic, and, in general, ethnic aspects still lack relevance in the neuroimaging literature. Furthermore, most studies in functional resonance with BD and SCZ have evaluated Caucasian populations, notably from Europe, the United States, and, in the last ten years, participants of Asian origin (Fearon et al., 2006; Gong et al., 2015; Hutchinson et al., 1999). Conversely, in Africa and Latin America, there is a scarcity of studies evaluating functional network disturbances associated with mood or psychotic disorders. Therefore, an intriguing hypothesis would be whether the occurrence of functional MRI alterations usually described in SCZ and BD would have an equal presence in individuals of African and indigenous origin, populations with a substantial presence in some Latin American countries, notably Brazil. Despite the lack of neuroimaging evidence, community studies have reported the influence of ethnicity on the incidence and psychopathological expression of SCZ and BD. For instance, one study in London showed higher rates of psychotic and affective disorders among African-Caribbean individuals when compared to their neighborhoods of Caucasian background (Fearon et al., 2006; Gong et al., 2015; Hutchinson et al., 1999). Furthermore, one New Zealand investigation reported hallucinations and hetero aggression as more often than affective symptoms in members of the Mori group when compared to individuals of other ethnicities of the same geographical area (Tapsell and Mellsop, 2007).

In the present study, we aim at characterizing the sociodemographic and the neurofunctional profile of individuals with SCZ and BD of non-European ancestry (non-EA), for instance, African and indigenous backgrounds. Our primary purpose is to investigate whether the neurofunctional alterations may reflect specific ethnical heterogeneity in both disorders. In addition, we want to explore how sociodemographic and psychopathological variables are related to particular neuronal disruption circuits in this population.