Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.

Mountain caribou (Rangifer tarandus caribou) are endangered in British Columbia and motorized backcountry recreation has been identified as a potential threat to their persistence. My objective was to test if fecal glucocorticoids (GCs), indicative of physiological effects of ecological stress in wildlife, could be used as a non-invasive tool to quantify stress response in free-ranging caribou exposed to motorized recreation. I validated an enzyme-linked immunosorbent assay (ELISA) to measure concentration of fecal GCs for R. tarandus using an adrenocorticotropic hormone (ACTH) challenge experiment on captive reindeer exposed to extreme variation in winter weather. Female reindeer expressed elevated fecal GCs 9-11 hrs after ACTH injection. Males showed no detectable increase, perhaps due to underdosing. Fecal GCs varied markedly in both sexes in response to natural variation in weather. Overall, my results indicated fecal assays can be used to track biologically meaningful changes in adrenal activity in R.tarandus. I investigated the effects of motorized recreation on stress hormone production by measuring GCs in feces of mountain caribou exposed to snowmobile and heli-ski activity. Concentrations of fecal GCs in snowmobile and heli-ski areas were higher than those measured from caribou in areas where motorized recreation was not allowed. Caribou sampled up to 4km. 8km and I0 km distant from snowmobile activity showed elevated fecal GCs when compared to those sampled further from snowmobile activity areas. Other variables with a significant effect on fecal GCs included reproductive state, snow, aspect. minimum ambient temperature, and daily temperature range. My study indicates that measurement of fecal GCs provides a useful, noninvasive approach in the evaluation of physiological effects of environment, reproductive state, and human-induced stressors on free-ranging mountain caribou. Although research on many species indicates that chronically elevated GCs carry a variety of physiological costs, more study is needed to know whether GCs can be used as an index of human impact on population health or trend.

[Truncated abstract] Obesity is rapidly increasing in prevalence and has significant physical and mental health implications. Stress, a general term referring to factors indicative of psychological strain such as depression and anxiety, has been identified as both a cause and consequence of weight gain and obesity in some individuals. In previous research, overeating in response to stress has been investigated as either a means of mood regulation or as a response to strict dietary restraint. Cortisol, a steroid hormone that increases in response to stress, has also been linked with increased food intake in both animal and human studies. Thus, cortisol may be an additional factor contributing to overeating and weight gain in response to stress. If stress does lead to overeating and weight gain, it is also likely that stress will inhibit attempts made by obese individuals at weight loss. The first study of this thesis was a repeated measures treatment study in which the associations of stress and cortisol levels with baseline body mass index and subsequent weight loss were investigated among females participating in a cognitive behavioural weight management programme. A cross-sectional analysis prior to treatment commencement showed that the association of stress and depression with body mass index was moderated by the severity of obesity. Dichotomous thinking, a cognitive style in which events are viewed in polarised 'black and white' terms, mediated the associations of both depression and eating disorder symptomatology with BMI. ... The second study of this thesis was a controlled laboratory-based examination of food intake following an acute psychological stressor. It was hypothesised that high baseline levels of psychological stress, such as depression and anxiety, would be associated with greater increases in negative mood and cortisol levels in response to the acute stressor, both of which, in turn, would be associated with greater food intake. Contrary to the hypothesis, baseline levels of psychological stress were not associated with the extent to which negative mood and cortisol levels increased following the acute stressor. The extent to which negative mood, but not cortisol, increased following acute stress was significantly positively associated with food intake. The results do not support the hypothesis that high cortisol levels are predictive of increased food intake in human females, although the results may have been affected by the broad participant inclusion criteria. The results suggest that increases in negative mood lead to increases in food intake, although it is argued that this is unlikely to be a general effect and suggestions for future research are made. The overall aim of this research was to examine whether stress and cortisol were associated with weight status, acute changes in eating behaviour and changes in weight in the medium-term. The results are discussed in relation to this aim, wth particular focus on the differences between treatment-seeking and community samples, implications for the treatment of obesity (especially when the individual is also experiencing high levels of depression), prevention of weight gain and possible future studies of the effects of stress and depression on weight change and eating behaviour.

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2006 / Typescript (photocopy)

Made available in DSpace on 2016-06-02T19:32:11Z (GMT). No. of bitstreams: 1 DissGHDP.pdf: 1446855 bytes, checksum: b44d0b337ad1c73932cf0a253c2bdad6 (MD5) Previous issue date: 2004-04-30 / Universidade Federal de Sao Carlos / Copper is an essential trace-element for all live organisms however, when its concentration is high in the aquatic environment, copper is potentially toxic. Most physiological changes caused by copper in fish has been analyzed after acute exposure (96h). The aim of this study was investigate the physiological responses of Prochilodus scrofa to stress, during acute copper exposition (24, 48, 72 and 96 hours) and recovery period after animal transference to clean water, and the time necessary to recovery after animals transference to clean water. The changes associated to fish transference to experimental systems were also evaluated. Juveniles Prochilodus scrofa were acclimated during 30 days and then fish were sampled to take blood for pH, hematocrit, plasma cortisol glucose and ions (Na+, Cl- e K+) analyses and specific Na+/K+-ATPase activity of gills. The remaining fish were divided in two groups: control (C) and exposed to copper (CU) and transferred to glass aquariums where was kept for 4 days. CU groups were exposed to copper (96h-CL50 = 29 µgCu L-1). Sampling was done 1, 2, 3 and 4 days of copper exposure. Surviving fish were then transferred to aquariums with flowing water without copper and sampling was done 1, 2, 7, 15 and 30 days of recovery. Blood sampling was taken for the same analyses above cited. Plasma cortisol concentration increased 300 a 400% in control and copper exposed groups related to acclimated fish, plasma glucose increased 800% only in the copper exposed groups during the exposure period and returned to normal levels in the 2nd day of recovery. In general, the changes in plasma ion (Na+, Cl- e K+) concentrations and pH were not significant in relation to those of acclimated fish however, significant changes were found between the values of control and copper exposed groups during copper exposure and recovery period. The activity of Na+/K+-ATPase of gills was lower in the CU group during the copper exposure period and on the 1st day of recovery. The hematocrit increased during metal exposure but on the 1st day of recovery reached the normal values. Although changes were found on the analyzed parameters, on the 7th days after the transference to clean water all parameters evidenced a tendency to recovery the physiological changes reaching the values of acclimated fish. The present study showed that the stress responses to copper exposure is complex and P. scrofa presents high susceptibility to handling evidencing the importance of comparative analyses involving acclimated and/or unstressed fish together with the controls and exposed fish to a given stressor. / O cobre é um elemento-traço essencial a todos os organismos, entretanto quando em alta concentração no meio aquático pode ser potencialmente tóxico. As alterações fisiológicas causadas pelo cobre em peixes têm sido analisadas, em geral, após exposições agudas (96h). O presente estudo teve como objetivo avaliar as alterações fisiológicas associadas ao estresse, durante o período de exposição aguda ao cobre e o período de recuperação em água sem a presença de cobre. As alterações provocadas pelo estresse associado à transferência dos animais para os sistemas experimentais também foram avaliadas. Prochilodus scrofa jovens foram aclimatados durante 30 dias e posteriormente animais foram amostrados e o sangue coletado para análise de pH e hematócrito sangüíneos, cortisol, glicose e íons (Na+, Cl- e K+) plasmáticos e determinação da atividade da enzima Na+/K+-ATPase das brânquias. Os animais remanescentes foram divididos em dois grupos controle (C) e exposto ao cobre (CU) e transferidos para aquários de vidro onde permaneceram durante 4 dias. O grupo CU foi exposto ao cobre (CL50-96h = 29 µgCu L-1). As amostragens foram efetuadas após 1, 2, 3 e 4 dias de exposição ao cobre. Os animais sobreviventes foram então transferidos para aquários com água corrente sem cobre e amostragens foram efetuadas após 1, 2, 7, 15 e 30 dias de recuperação. Amostras de sangue foram coletadas para as mesmas análises citadas acima. A concentração de cortisol plasmático aumentou 300 a 400% nos grupos controle e expostos ao cobre em relação aos animais aclimatados e a glicose plasmática aumentou 800% somente nos animais expostos ao cobre durante o período de exposição e retornaram aos níveis dos animais aclimatados no 2o dia de recuperação. As alterações nas concentrações dos íons plasmáticos (Na+, Cl- e K+) e pH, em geral, não foram significantes em relação aos animais aclimatados, mas alterações significativas foram observadas entre os grupos controle e exposto ao cobre durante a exposição ao cobre e recuperação. A atividade da enzima Na+/K+-ATPase nas brânquias foi menor no grupo CU durante a exposição ao cobre e 1o dia de recuperação. O hematócrito aumentou significativamente durante a exposição ao metal, mas após o primeiro dia de recuperação retornou aos valores normais. Embora tenha ocorrido alteração nos parâmetros analisados, após o sétimo dia de transferência para água sem cobre houve uma tendência de recuperação em todos os aspectos fisiológicos. Os resultados do presente estudo mostraram que a resposta ao estresse por exposição ao cobre é complexa e que P. scrofa apresenta a alta susceptibilidade à manipulação evidenciando a importância de estudos que envolvem comparações com animais considerados aclimatados ou não estressados e animais de grupos controle e expostos a um dado estressor.

Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-13Bitstream added on 2014-06-13T20:21:10Z : No. of bitstreams: 1 fagundes_m_dr_jabo.pdf: 453907 bytes, checksum: d061547f66dba810d753d5851eba9a59 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O número de espécies cultivadas no Brasil vem aumentando, surgindo a necessidade de um melhor conhecimento da fisiologia e das técnicas de produção, incluindo o pintado (Pseudoplatystoma corruscans). O objetivo deste estudo foi avaliar o perfil circadianas do cortisol e da glicose do pintado sem a presença de agente estressor e respostas fisiológicas de estresse (níveis sanguíneos de cortisol e glicose, glicogênio hepático e muscular, níveis plasmáticos de cloreto e osmolaridade e hematócrito, número e volume das células vermelhas sanguíneas e hemoglobina) em indivíduos juvenis quando submetidos a diferentes tipos de agentes estressores comuns no manejo da criação (transporte de 12 horas, exposição à luz e escuro por 24 horas e exposição a três anestésicos, benzocaína, fenoxietanol e óleo de cravo). Não foram observadas diferenças estatísticas no perfil circadiano dos indicadores analisados, mas os valores de cortisol tinham variação de perfil no período diurno e noturno, com picos na instalação em condição de escuro e de claridade. A glicemia não mostrou correlação com o perfil do cortisol, mantendo valores mais constantes no período noturno. No experimento de transporte, os níveis de cortisol mostraram aumento após o transporte acompanhado por uma queda progressiva, vindo a alcançar valores inferiores ao do controle 48, 72 e 96 horas após a operação. A glicose se elevou após transporte retornando aos valores basais em 72 horas. Os níveis de lipídeo muscular aumentaram após o transporte retornando a valores próximos aos normais em 72 horas. O colesterol e a proteína aumentaram. O cloreto teve redução após transporte, bem como o hematócrito, número de células vermelhas e hemoglobina. Os dados metabólicos sugerem o uso de outra fonte que não a glicose para sustentar a demanda energética do estresse... / The number of species farmed in Brazil, including the pintado (Pseudoplatystoma corruscans) has been increasing making necessary better knowledge of their physiology and farming techniques. The aim of this study was evaluate the circadian variations of blood cortisol and glucose without stresfull agents and physiological responses (blood levels of cortisol and glucose; liver and muscle glycogen; plasma chloride and osmolarity; hemathocrit, number e volume of red cells and hemoglobin) of juvenile fish submitted to different farming conditions (12h transport; alteration of photoperiod - 24 h exposure to continuous light or continuous darkness; exposure to benzocaine, phenoxyethanol and clove oil). There was no statistical among cortisol levels, but numerically the day profile was different of the night profile, showing peaks of cortisol secretion at the set up of the darkness and light. Blood glucose was not correlated to cortisol profile and had the levels more constant during the night. In the transport experiment, the cortisol levels increased along the procedure followed by a gradual reduction that reached values below the control 48, 72 and 96 h after the operation. Glucose increased after transport returning to basal levels within 72h as well muscle lipid levels. Blood colesterol and protein also increased. Chloride was reduced after transport as well as hematocrit, number of red cells and hemoglobin. Metabolic data suggest the use of another energy source in place of glucose to attend the stress demand. In the experiment in which fish were submitted to 24 h of light or darkness, blood cortisol did not differ statistically, but the values found in fish under 24 h of light were numerically higher compared to those of fish under darkness and both compared to control fish. Glicemia was numerically reduced in fish under darkness. No osmorregulatory disturbance was seen... (Complete abstract click electronic access below)

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-12-04T20:41:47Z No. of bitstreams: 1 ChristianCamiloGarciaLopez_DISSERT.pdf: 2196830 bytes, checksum: 3aec0c3604ab6bb915398d3380ba6a61 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-12-07T19:26:20Z (GMT) No. of bitstreams: 1 ChristianCamiloGarciaLopez_DISSERT.pdf: 2196830 bytes, checksum: 3aec0c3604ab6bb915398d3380ba6a61 (MD5) / Made available in DSpace on 2017-12-07T19:26:20Z (GMT). No. of bitstreams: 1 ChristianCamiloGarciaLopez_DISSERT.pdf: 2196830 bytes, checksum: 3aec0c3604ab6bb915398d3380ba6a61 (MD5) Previous issue date: 2017-06-05 / O comportamento de risco est? sob influ?ncia de fatores neuropsicol?gicos, neuroend?crinos, sociais e individuais. O perfil hormonal, estados de humor, bem como status de relacionamento rom?ntico, sexo e idade est?o todos implicados neste comportamento. Embora ainda n?o haja um consenso claro sobre o quanto esses fatores modulam o processo de tomada de decis?o sob risco. O presente estudo avaliou o efeito de estados psicol?gicos, o envolvimento em um relacionamento rom?ntico, e testosterona (pr?-natal e ativa??o) e cortisol sobre o comportamento de risco; bem como a reatividade desses horm?nios no desempenho de uma tarefa de risco. Estudantes universit?rios entre os 21 e 30 anos (n = 49) participaram da investiga??o. O comportamento em rela??o ao risco foi medido utilizando uma escala de propens?o ao risco (EPR) e uma tarefa de tomada de decis?o sob risco, Columbia Card Task (CCT). Um efeito negativo foi encontrado entre uma baixa propor??o 2D:4D e a atitude em rela??o ao risco na dimens?o sa?de/seguran?a no EPR, quando a testosterona basal e o cortisol foram baixos ou altos. Enquanto, os participantes com alta propor??o 2D:4D, mostram um maior comportamento de risco no CCT, associado com altos n?veis de testosterona basal e baixos do cortisol. Um aumento na testosterona foi relacionado com um melhor desempenho, e menos tempo gasto no CCT. Estar envolvido em um relacionamento rom?ntico foi associado a uma maior avers?o ao risco no CCT. Os participantes com maior pontua??o para depress?o e ansiedade tinham uma atitude mais elevada em rela??o ao risco no CCT. Estes resultados sugerem que uma elevada exposi??o pr?-natal ? testosterona fortalece a atitude em rela??o ao risco, diminuindo o efeito activacional da testosterona e do cortisol, bem como a plasticidade comportamental, sugerindo que a testosterona activacional n?o ? cr?tica para a express?o deste tra?o comportamental. Por outro lado, n?veis mais baixos de testosterona pr?-natal permitem maiores efeitos da ativa??o hormonal e plasticidade comportamental dependendo do contexto. A reatividade da testosterona pode promover uma avers?o ao risco para obter um resultado mais favor?vel. Nossas descobertas suportam as descobertas de que estar envolvido em um relacionamento rom?ntico, est? relacionado com um maior risco assumindo comportamento em favor da sua aptid?o evolutiva. Tamb?m ? proposto que, em contextos de alto risco, os participantes com caracter?sticas mais depressivas e ansiosas podem levar a comportamentos mais arriscados. / Risk-taking behavior is influenced by neuropsychological, neuroendocrine, social and individual factors. However, there is still no clear consensus on the extent to which these factors modulate decision-making under risk. The present study evaluated the effect of psychological states, romantic partnership, testosterone (prenatal and activational) and cortisol on risk-taking behavior, as well as the reactivity of these hormones on the performance of a risk-taking task. University students aged between 21 and 30 years (n = 49) participated in the investigation. The behavior towards risk was measured using a self-reported risk propensity scale (RPS) and for the decision-making task under risk, the Columbia Card Task (CCT). A negative effect was found between a low 2D:4D ratio and the attitude towards risk in the health/safety dimension of the RPS, when basal testosterone and cortisol were either low or high. On the other hand participants with a high 2D:4D ratio show greater risk- taking behavior in the CCT, associated with high basal testosterone and low cortisol. An increase in testosterone was related to better performance and less time spent on the CCT. Being involved in a romantic relationship was associated with higher aversion to risk on the CCT. Participants with higher depression and anxiety scores had a greater attitude towards risk on the CCT. These results suggest that high prenatal testosterone exposure strengthens the attitude toward risk, decreasing the activational effect of testosterone and cortisol, as well as behavioral plasticity, suggesting that activational testosterone is not critical for the expression of this behavioral trait. However, lower levels of prenatal testosterone allow greater hormonal activational effects and behavioral plasticity depending on the context. Testosterone reactivity might promote aversion to risk to produce a more favorable outcome. Our findings show that being involved in a romantic relationship is related to being more prone to risk taking behavior in favor of evolutionary fitness. It is also proposed that in situations high-risk participants with more severe depressive and anxiety traits may lead to an increase in risky behavior. / 2018-10-01

Psychotic-like experiences (PLEs) are prevalent occurrences deemed comparable with the symptoms of psychosis, but not sufficiently severe to warrant a diagnosis upon clinical presentation. Their presence is associated with several adverse clinical outcomes: the onset of various common mental health disorders (e.g. anxiety, mood, substance abuse), poorer functioning, non-remission and relapse. Sleep and circadian rhythm disruption (SCRD) is observed in 30-80% of patients with psychosis. The omnipotence of SCRD across all phases of the disorder (including the prodromal, acute, chronic and residual phases) raises the question as to whether SCRD may directly contribute to the development of psychosis. Assuming that PLEs are along the same continuum to developing psychosis, a logical next step to further disentangle the sleep-psychosis relationship is to examine whether SCRD relates to the experience of PLEs and whether this relationship is bi-directional. This thesis begins by examining the core predictions made by a continuum model of understanding psychosis and how specific parameters of sleep may influence PLEs. A smaller high-definition cross-sectional study follows, examining biological underpinnings (electroencephalography (EEG), electrocardiography (ECG), endogenous melatonin rhythms and actigraphy) of a complaint of poor sleep and their relation to the occurrence of PLEs. We then refocus on which parameters of sleep are most integral to the sleep-PLE relationship and close with an investigation of how Hypothalamic Pituitary Adrenal (HPA) axis activity may further our knowledge of this relationship. The findings of this thesis demonstrate specificity in the parameters of sleep shown to impact certain PLEs. The importance of objective sleep and biologically driven measures in this line of research are underscored, with group differences in EEG, ECG and melatonin. This thesis also highlights dissociative symptomatology as a candidate mediator for the sleep-psychosis relationship, and emphasises the ties between paranoia and negative affect. Finally, this thesis also illuminates the challenges of examining the relationship between sleep and PLEs in isolation, and suggests that they must be considered within the broader framework of co-existing mental health problems.

abstract: Dysregulated cortisol has been linked to a variety of adverse physical and psychological consequences. Stressors in the childhood family environment can influence cortisol activity throughout development. For example, research has shown that both infants and children of depressed mothers exhibit altered levels of cortisol compared to infants and children of non-depressed mothers. It is unclear, however, whether exposure to maternal depression in childhood and adolescence is related to cortisol activity at later stages of development. The current study examined the longitudinal relation between maternal depressive symptoms during late childhood (9-12 years old) and adolescence (15-19 years old) and cortisol activity in offspring in young adulthood (24- 28 years old) in a sample of 40 young adults and their mothers. Maternal depressive symptoms were prospectively assessed at four time points across the 15 year study. Cortisol samples were collected from young adult offspring at the final time point. Findings revealed that higher levels of maternal depressive symptoms during late childhood were associated with lower total cortisol output in young adulthood. Results suggest that attenuated cortisol levels, which put these young adults at risk for a variety of stress-related physical and psychological illnesses, may be a long-term consequence of exposure to maternal depression,. Depressive symptoms in mothers during their child's adolescence, however, did not relate to cortisol output. These findings suggest a sensitive period in late childhood during which the development of HPA activity may be susceptible to the environmental stressor of maternal depression. / Dissertation/Thesis / M.A. Psychology 2011

Delirium is a severe neuropsychiatric syndrome, characterised by the acute onset of inattention, altered level of arousal, and other mental status abnormalities. Delirium is extremely common in acute stroke, affecting at least 1 in 5 such patients admitted to hospital. It is a serious complication of stroke, being associated with higher mortality, longer length of hospital stay and higher dependency at discharge. The pathophysiology of delirium is not completely understood, and there are no specific treatments. This thesis investigated the role of cortisol in the development of delirium after stroke and also investigated the role of delirium and of cortisol in the development of cognitive impairment in the 12 months after stroke. The thesis specifically investigated whether levels of cortisol in saliva are elevated in delirium and also whether there is a loss of the normal diurnal rhythm in delirium, evidenced by elevated afternoon salivary cortisol levels and reduced morning level to afternoon level ratio. The thesis also investigated whether cortisol levels are persistently elevated in the year after stroke in those who developed delirium and whether cortisol levels are associated with cognitive decline. Finally it investigated whether acute and/or chronic changes seen on Computed Tomography (CT) brain scans taken around the time of stroke onset are associated with the development of delirium after stroke A longitudinal cohort study was conducted in 95 participants aged 60 years or over, who were admitted to hospital with a clinically confirmed stroke. Participants gave informed consent, or proxy consent was obtained if they lacked capacity to consent. At baseline participants underwent brief cognitive testing and were then assessed for the presence of delirium, using DSM IV criteria, at regular intervals during the first two weeks after stroke. At each assessment a saliva sample was collected in the morning and in the afternoon, to measure cortisol. Participants were then visited at 1 month, 4 months and 12 months after stroke onset, at which point they were assessed for the presence of delirium, further saliva samples were taken and a cognitive test battery was completed. 26 (27%) participants developed delirium during the course of the study period. The study found elevated salivary cortisol levels in those with delirium at up to 4 months after stroke, but at 12 months there was no difference between the delirium and no delirium group. A loss of the diurnal rhythm was seen in those who developed delirium at 5 days after stroke, but the diurnal variation had returned to a normal pattern at follow-up. However, in a multivariate analysis, controlling for age, sex, stroke severity (NIHSS), current illness burden (APACHE II), chronic illness burden (CCI) and prior cognitive impairment (IQCODE), neither median salivary cortisol levels in the first two weeks after stroke, nor the ratio of morning to afternoon cortisol levels were independent predictors of delirium diagnosis, although median 9am cortisol approached significance (OR=0.95, 95% confidence interval (CI) 0.89-1.01, p=0.08). In a random effects logistic regression analysis, the probability of developing delirium decreased over time from stroke onset and increased per unit increase in salivary cortisol (nmol/L), however this effect was not statistically significant (OR 1.02, CI 0.84-1.19 P=0.70 for morning cortisol and OR 1.05, CI 0.82-1.25 p=0.46 for afternoon cortisol). Global cognition, measured by the MoCA, was significantly poorer in the delirium group at each time point throughout the 12 months after stroke. However, there was a trend towards improvement in MoCA scores in the whole cohort throughout the 12 month follow-up, with the exception of those who developed the most severe delirium. The presence of delirium at any point during the 12 month follow-up did not affect the rate of change of the MoCA scores over the 12 months after stroke. The presence of brain atrophy identified on admission CT brain scans was independently associated with delirium (OR 3.7, CI 1.15-11.88, p=0.02), however the presence of a visible acute or chronic stroke lesion and the presence of white matter lesions were not. Finally, those who developed delirium had a worse functional outcome, longer length of hospital stay and were more likely to require institutional care or a package of care at home, compared with those who did not develop delirium. This thesis has contributed to our understanding of the mechanisms and phenomenology of delirium after stroke, and has also highlighted areas for further research which will be required to unpick the complex pathophysiology of delirium.