Centre for Youth Mental Health - Research Publications
Permanent URI for this collection
Search Results
1 - 3 of 3
-
ItemGrip Strength Is Associated With Cognitive Performance in Schizophrenia and the General Population: A UK Biobank Study of 476 559 Participants(OXFORD UNIV PRESS, 2018-07)BACKGROUND: Handgrip strength may provide an easily-administered marker of cognitive functional status. However, further population-scale research examining relationships between grip strength and cognitive performance across multiple domains is needed. Additionally, relationships between grip strength and cognitive functioning in people with schizophrenia, who frequently experience cognitive deficits, has yet to be explored. METHODS: Baseline data from the UK Biobank (2007-2010) was analyzed; including 475397 individuals from the general population, and 1162 individuals with schizophrenia. Linear mixed models and generalized linear mixed models were used to assess the relationship between grip strength and 5 cognitive domains (visual memory, reaction time, reasoning, prospective memory, and number memory), controlling for age, gender, bodyweight, education, and geographical region. RESULTS: In the general population, maximal grip strength was positively and significantly related to visual memory (coefficient [coeff] = -0.1601, standard error [SE] = 0.003), reaction time (coeff = -0.0346, SE = 0.0004), reasoning (coeff = 0.2304, SE = 0.0079), number memory (coeff = 0.1616, SE = 0.0092), and prospective memory (coeff = 0.3486, SE = 0.0092: all P < .001). In the schizophrenia sample, grip strength was strongly related to visual memory (coeff = -0.155, SE = 0.042, P < .001) and reaction time (coeff = -0.049, SE = 0.009, P < .001), while prospective memory approached statistical significance (coeff = 0.233, SE = 0.132, P = .078), and no statistically significant association was found with number memory and reasoning (P > .1). CONCLUSIONS: Grip strength is significantly associated with cognitive functioning in the general population and individuals with schizophrenia, particularly for working memory and processing speed. Future research should establish directionality, examine if grip strength also predicts functional and physical health outcomes in schizophrenia, and determine whether interventions which improve muscular strength impact on cognitive and real-world functioning.
-
ItemAdjunctive nutrients in first-episode psychosis: A systematic review of efficacy, tolerability and neurobiological mechanisms(WILEY, 2018-10)AIM: The effects of nutrient-based treatments, including adjunctive vitamin or antioxidant supplementation, have been explored extensively in long-term schizophrenia. However, no systematic evaluation of trials in "first-episode psychosis" (FEP) has been conducted, despite the potential benefits of using these treatments during the early stages of illness. Therefore, we aimed to review all studies examining efficacy, tolerability and the biological mechanisms of action, of nutrient supplementation in FEP. METHODS: A systematic review of electronic databases was conducted from inception to July 2017. All information on feasibility, clinical outcomes and mechanistic findings from nutrient supplementation clinical trials was extracted and systematically synthesized. RESULTS: Eleven studies with a total of 451 patients with FEP (from 8 independent randomized controlled trials) were eligible for inclusion. Six studies examined omega-3 fatty acids, with inconsistent effects on psychiatric symptoms. However, mechanistic studies found significant improvements in hippocampal neuronal health and brain glutathione. Antioxidants "n-acetyl cysteine" (n = 1) and vitamin C (n = 2) also improved oxidative status in FEP, which was associated with reduced psychiatric symptoms. No benefits were found for vitamin E (n = 1). Finally, one study trialling the amino acid taurine, showed significant improvements in positive symptoms and psychosocial functioning. CONCLUSION: There is preliminary evidence that taurine improves outcomes in FEP, whereas effects of omega-3 and antioxidant vitamins/amino-acids are inconsistent; perhaps mainly benefitting patients with high levels of oxidative stress. Future studies should evaluate multifaceted dietary and supplementation interventions in FEP; targeting-specific nutritional deficits and the range of aberrant biological processes implicated in the disorder.
-
ItemThe Validity and Value of Self-reported Physical Activity and Accelerometry in People With Schizophrenia: A Population- Scale Study of the UK Biobank(OXFORD UNIV PRESS, 2018-11)BACKGROUND: Previous physical activity (PA) research in schizophrenia has relied largely upon self-report measures. However, the accuracy of this method is questionable. Obtaining accurate measurements, and determining what may influence PA levels in schizophrenia, is essential to understand physical inactivity in this population. This study examined differences in self-reported and objectively measured PA in people with schizophrenia and the general population using a large, population-based dataset from the UK Biobank. METHODS: Baseline data from the UK Biobank (2007-2010) were analyzed; including 1078 people with schizophrenia (54.19 ± 8.39 years; 55% male) and 450549 without (56.44 ± 8.11; 46% male). We compared self-reported PA with objectively measured accelerometry data in schizophrenia and comparison samples. We also examined correlations between self-report and objective measures. RESULTS: People with schizophrenia reported the same PA levels as those without, with no differences in low, moderate, or vigorous intensity activity. However, accelerometry data showed a large and statistically significant reduction of PA in schizophrenia; as people with schizophrenia, on average, engaged in less PA than 80% of the general population. Nonetheless, within the schizophrenia sample, total self-reported PA still held significant correlations with objective measures. CONCLUSIONS: People with schizophrenia are significantly less active than the general population. However, self-report measures in epidemiological studies fail to capture the reduced activity levels in schizophrenia. This also has implications for self-report measures of other lifestyle factors which may contribute toward the poor health outcomes observed in schizophrenia. Nonetheless, self-report measures may still be useful for identifying how active individuals with schizophrenia relative to other patients.