Dementia incidence is rising as our population is ageing. There is growing evidence for the protective effect of physical activity against cognitive decline. However, there are inconsistent results across studies despite the large number of high quality trials. The role of psychosocial factors on cognitive outcomes was investigated in the present thesis due to the evidence of their relationship with physical activity and for their effect on cognitive ability in other contexts. The psychosocial factors investigated were attitudes towards ageing, perceived control, mental health, and self-efficacy using cross-sectional studies and pilot randomised controlled exercise trials to test proof of concept. Study 1a found that more positive attitudes towards ageing were associated with better self-reported subjective and functional health. Perceived control mediated the effect of attitudes related to psychosocial loss with ageing and physical activity level mediated the effect of attitudes related to psychological growth with ageing on subjective health. Attitudes towards ageing mediated the effect of perceived control on functional health. Study 1b and 1c explored attitudes towards ageing in more detail and found that older adults attitudes towards ageing were similarly negative to those held by young adults in the UK. A substantial proportion of attitudes reported by older adults related to physical functioning and cognitive ability. Attitudes towards ageing in China were more positive than those in the UK which suggested a potential relationship with socio-cultural and environmental factors and possible scope for attitude change from an intervention. A higher proportion of attitudes towards ageing reported in the UK were related to physical functioning and cognitive ability compared to China. These findings highlighted the potential for attitudes towards ageing and perceived control to play a role in the context of physical activity, cognitive ability and subjective health. Study 2a found that physical, social, and mental activities were independently associated with cognitive ability which informed the study design of exercises to include a pseudo control group that controlled for social interaction and mental stimulation. Study 2b found that mental health partially mediated the association between walking and cognitive ability. In older adults with better mental health, walking was not associated with cognitive ability. In older adults with poorer mental health walking was associated with better cognitive ability. Study 3 utilised available data from a pilot resistance training randomised controlled trial with middle-aged adults to test proof of concept for the role of psychosocial factors in this context. Preliminary evidence was provided for a potential association between improvements on some psychosocial factors and cognitive performance improvements. The associations of cognitive gains with psychosocial factors were independent to those of physical fitness improvements, which may indicate a potentially additive effect. Study 4 assessed the feasibility of the pilot randomised controlled trial of resistance training with older adults. Recruitment was successful but high drop-out rates lead to between group differences in age and baseline cognitive ability. Adaption of exercise to suit individual capabilities increased participation and adherence of those who completed the programmes was high. The limited usefulness of analysis by group was highlighted due to the large variation in response to exercise within groups on psychosocial and cognitive measures. Older participants were more likely to report a negative effect of resistance training on psychosocial measures, which indicated a potential confound on outcomes of exercise interventions with older adult populations. Preliminary analysis indicated that improvements on some psychosocial factors were associated with domain specific cognitive gains. This association could be due to a variety of mechanisms, such as meta-cognitive motivational processes, for example sustained effort and attention and the use of memory strategies. However, these findings need to be interpreted with caution due to the parallel change of variables, small sample size and feasibility and pilot nature of the interventions. There is a potential implication for the design of exercise programmes if they facilitate improvements in psychosocial factors as well as physical fitness, then this could enhance the effect of exercise on cognitive outcomes. Future research should replicate these studies with larger sample sizes to further understand the role of psychosocial factors in cognitive gains during exercise interventions in older adults.

Research shows that a considerable number of children and adolescents suffer needlessly from psychological problems and only about 50% of those receive the necessary services. Considering the impact of untreated child psychological problems on problems in adulthood, it is important to examine the influence of attitudes on seeking mental health service for children. Currently, no known measure exists to measure attitudes toward mental health services for children. Building on previous research, the goal of the present study was to develop a measure of individuals' attitudes toward mental health services for children. Using confirmatory factor analysis, the factor structure was assessed using a sample of university students (N = 250). In addition, several hypotheses were tested examining the influence of previous experience with mental health services on attitudes towards psychological services and mental health stigma. Finally, differences in child characteristics on intended help-seeking were examined. The measure developed consists of 26-items scored from 0 (strongly disagree) to 5 (strongly agree). Overall, results indicated that the 3-factor structure of the measure developed was valid and reliable. Also, consistent with previous research on mental health services results supported the hypotheses of the current study. Future research will examine whether the 3-factor structure is replicated using a sample of parents.

With the current military mental health crisis, it is important to understand the role of the leader in military mental health. First, the impact of military leader behaviors on the well-being of military personnel is reviewed. Next, the role of leader attitudes as a precursor to leader behaviors is discussed. The relation of leader behaviors to leader personality using the NEO Five Factor Model (FFM) is reviewed, as well as the relation of prejudicial attitudes to the NEO FFM personality factors. A research project is described that attempted to draw these concepts together, assessing the NEO FFM personality dimensions and mental health attitudes of US Army ROTC cadets, the future leaders of the US Army. No significant relations were observed between NEO FFM personality traits and mental health attitudes, even after controlling for Impression Management. Also, the predicted positive correlation between positive mental health attitudes and Impression Management was not found. These results suggest that more research and more refined measures are needed in the area of leader attitudes toward soldier mental health problems, and how those attitudes might impact the soldiers.