Objective: To test the hypothesis that genetic variations of cannabinoid receptors contribute to the pathophysiology of cognitive deficits in schizophrenia. Methods: In this genetic association case-control study, cannabinoid receptor polymorphisms CNR1 rs12720071 and CNR2 rs2229579 were tested for association with neurocognitive performance in 69 patients with schizophrenia and 45 healthy controls. Neurocognition was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS). Results: We found a consistent association between CNR1 rs12720071 polymorphism and the cognitive performance of patients in several cognitive domains. Patients with C/C polymorphism presented significantly worse performance in motor speed, verbal fluency, attention/processing speed and reasoning/problem solving. Conclusion: Although limited, our data support the hypothesis that CNR1 variations may be associated with the pathogenesis of cognitive deficits of schizophrenia.

Resumo Objetivo: Investigar os determinantes de sobrecarga familiar numa amostra de pacientes com esquizofrenia e seus cuidadores. Métodos: Trinta e um pacientes com esquizofrenia e seus principais cuidadores participaram do estudo. Variáveis sociodemográficas foram analisadas por meio de uma entrevista semiestruturada, e sintomas positivos e negativos foram quantificados através da Positive and Negative Syndrome Scale (PANSS). O desempenho cognitivo foi mensurado pela Schizophrenia Cognition Rating Scale (SCoRS). A Escala de Avaliação da Sobrecarga dos Familiares (FBIS) avaliou os níveis de sobrecarga entre os cuidadores. As interações entre as variáveis foram verificadas por meio do coeficiente de correlação de Pearson e de análise de regressão linear. Resultados: Os escores objetivos e subjetivos da FBIS foram 1,9 [desvio padrão (DP) 0,5] e 2,4 (DP 0,6), respectivamente. Sobrecarga objetiva se correlacionou positivamente com sintomas positivos e negativos, e com prejuízos cognitivos. A sobrecarga subjetiva se correlacionou positivamente com sintomas positivos, e negativamente com a idade de início da doença. Os sintomas positivos e negativos e os prejuízos cognitivos contribuíram com 47,6% da variância da sobrecarga objetiva, sendo que sintomas negativos foram responsáveis independentemente por 30,3%. A idade de início da doença, os pais na posição de cuidadores e os sintomas positivos contribuíram com 28% da variância da sobrecarga subjetiva, sendo que a idade de início da doença contribuiu independentemente com 20,3%. Conclusões: Variáveis sociodemográficas e clínicas dos pacientes são importantes determinantes de sobrecarga familiar na esquizofrenia. A sobrecarga objetiva pode ser predita por sintomas, especialmente os negativos. A sobrecarga subjetiva pode ser predita por sintomas e características sociodemográficas, particularmente a idade de início da doença.

Abstract Objectives: To investigate the determinants of family burden in a sample of patients with schizophrenia and their caregivers. Methods: Thirty-one stable patients with schizophrenia and their main caregivers were recruited. Sociodemographic variables were assessed in a semi-structured interview, and positive and negative symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Cognitive performance was assessed with the Schizophrenia Cognition Rating Scale (SCoRS). Levels of burden on caregivers were assessed with the Family Burden Interview Schedule (FBIS). Interactions among variables were analyzed using Pearson correlations and linear regression analysis. Results: Objective and subjective FBIS scores were 1.9 (standard deviation [SD] = 0.5) and 2.4 (SD = 0.6) respectively. Objective burden correlated positively with positive and negative symptoms, and cognitive impairment. Subjective burden correlated positively with positive symptoms and negatively with mean age of disease onset. Positive, negative and cognitive symptoms accounted for 47.6% of the variance of objective burden, with negative symptoms accounting independently for 30.3%. Age of onset, parents as caregivers and positive symptoms accounted for 28% of the variance of subjective burden, with age of onset independently explaining 20.3%. Conclusion: Patients' clinical and sociodemographic variables are important determinants of family burden in schizophrenia. Objective burden is predicted by symptoms, particularly negative ones. Subjective burden is predicted by symptoms and sociodemographic variables, particularly age of disease onset.

Historically, measures of everyday functioning have focused exclusively on real-world performance. Despite the unquestionable value of “real-world functioning”, it has become clear that instruments for its assessment might not be as accurate as desirable. Functional capacity is a domain of everyday functioning that can be assessed through performance-based measures. In the last decade, functional capacity has become a cornerstone for the assessment of everyday functioning, since, alongside measures of real-world functioning, it provides a much more comprehensive picture of functional outcomes than any measurement alone. Functional capacity is more stable and less vulnerable to influence from environmental factors than other domains, and its correlation with cognitive functions has encouraged the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) project to suggest that a performance-based measure of functional capacity be included as a co-primary assessment of cognition in clinical trials. Functional capacity assessment instruments may be also useful in the evaluation of remission in schizophrenia. Validation of these instruments in different countries is desirable, and should always include cross-cultural adaptation; within large countries, adjustment for regional variations should be considered.