Schizophrenia is a highly heritable, common psychiatric disorder. Although onset generally occurs during adolescence, multiple lines of evidence point to a neurodevelopmental insult that occurs many years prior to the presentation of symptoms. Many different approaches have been used to elucidate the genetic risk factors and their impact; however, few unequivocal facts have been established. With a considerable amount of data publically available, integrative approaches look to leverage multiple data sources to identify coherent themes. This thesis investigates the neurodevelopmental hypothesis of schizophrenia by incorporating results from genome-wide association studies and copy number variation studies with gene expression datasets, with the overall aim of identifying functional pathways that may be disrupted in the aetiology of the disorder. This study used foetal and developmental expression datasets of the human brain and statistical approaches to characterise the expression profiles of schizophrenia risk genes. Both spatial profiles in the mid-foetal brain and temporal profiles across development were considered. Data from genome-wide association studies and copy number variation studies were used to test for an enrichment of risk genes; in addition the genetic overlap with bipolar disorder identified through genome-wide association studies was used for validation. Gene sets with a common expression profile enriched for schizophrenia variants were used to identify biological pathways and assessed for their polygenic contribution to schizophrenia risk. The results of this thesis converged on a common developmental expression profile for schizophrenia risk genes. Genes identified with this profile were shown to harbour multiple, common risk variants for schizophrenia and were implicated in epigenetic processes relating to the regulation of gene transcription. Together this suggests that schizophrenia associated genes are involved in brain development, particularly during foetal stages, and may play a role in the regulation of this process.

The diagnosis and management of normal pressure hydrocephalus (NPH) remains controversial. The aim of this prospective study was to assess the usefulness of clinical and radiological criteria together with supplemental neuropsychological and gait tests, cerebrospinal fluid (CSF) hydrodynamic studies and external lumbar drainage (ELD) in identifying those who may respond to a shunt and to compare the outcomes with the non-shunted patients at one year. Method: Forty patients with a clinical diagnosis of NPH were prospectively studied according to a fixed management protocol. Resistance to CSF (Rcsf) was measured using a lumbar infusion study and an ELD was used to determine improvement in neuropsychological and gait tests following CSF drainage. Based on specific criteria those who showed improvement were shunted. Clinical and radiological outcomes were assessed at one year in all patients. Results: Twenty three (57.5%) patients were shunted. Improvement was observed in 74% of shunted patients, while 17% did not improve and 9% deteriorated following surgery. Age, etiology, presentation, duration of symptoms and presence of co-morbid factors were unrelated to outcome. Improvement was found in 63% of shunted patients with RCSF of 12 mmHg/ml/min or higher. The sensitivity was 64% with a positive predictive value of 68%. Both Rcsf testing and ELD enhanced the positive predictive outcome of shunt operation. Using the non-shunted patients as controls, the mean difference between the two groups over time differed significantly in all the neuropsychological tests and some gait test. Conclusions: No single test was able to predict overall success with shunting but the results showed that a high percentage of improvement could be achieved by using continuous ELD and a rigorous protocol. Greater improvements were observed in cognitive and gait function than in sphincter control. An Rcsf of 12mmHg/ml/min or more was related to better outcomes. Consideration was given to the significant limitations in the study design and outcome measures.

Depression is a significant global problem and is among the leading causes of disability worldwide. Depression in children and adolescents is associated with wide-ranging impairments and often marks the beginning of a lifelong, chronic illness. Early treatment and prevention of depression is therefore a major public health concern. Parental depression is one of the most consistently identified risk factors for depression in young people. Although depression is a highly heterogeneous disorder, most studies examining cross-generational depression risk have simply dichotomised parents into ‘depressed’ and ‘non-depressed’ groups and clinical characteristics beyond diagnostic status are rarely presented. In this thesis I examine how differences in clinical features of parental depression including variations in depression course, severity, timing and symptom manifestation differentially relate to offspring depression risk. Data were drawn from the Early Prediction of Adolescent Depression study. A three-wave longitudinal study of the offspring of 337 parents with a history of recurrent unipolar depression. Within this high risk group of offspring, specific clinical features of parental depression were identified that may serve as useful markers of current and/or future offspring depression risk. These included a recent episode of clinical depression, an episode involving severe impairment or hospitalisation and symptoms of appetite or weight loss. In addition, findings from this thesis highlight that there is considerable variability in the course of parent depression over time and suggest that any persistent symptoms of depression in parents, even those at low levels, may be clinically important in indexing offspring risk for depression symptoms. vi Findings highlight the importance of considering clinical characteristics of depression in parents beyond diagnostic status when examining cross-generational depression risk. The identification of subgroups of offspring who are at greatest risk can help ensure that clinical services and preventative interventions are targeted to those with greatest need.

This doctoral thesis examines the effectiveness of dialectical behaviour therapy for eating disorders, and explores the lived experience of women with eating distress who also have a history of trauma. The first chapter uses meta-analytic procedures to critically review the current literature to determine whether dialectical behaviour therapy can be regarded as an effective treatment for individuals with eating disorders. The treatment effects across a range of measures were explored, as well as a discussion of the methodological limitations and recommendations for future research. The implications for clinical practice are also considered. The second chapter is an empirical study using a qualitative approach to explore the experiences of eating distress and trauma in women. Women were interviewed to determine their views on the development, daily experience and treatment of their eating distress. The clinical implications and recommendations for future research are discussed, including methodological limitations. The final chapter provides a reflective account of the author’s experience of conducting sensitive research with women with eating distress.

This research thesis explores mental health professionals’ reactions to patient suicide and the emotional experiences of working in a Crisis Team. Chapter one is a literature review examining twelve empirical studies of the impact of patient suicide on mental health professionals and the resources they draw on to cope with the effects. The review revealed a range of personal and professional responses amongst professionals and highlighted the concept of blame in the coping process. Chapter two is a qualitative empirical study of seven clinicians’ emotional experiences of working in a UK Crisis Team. Interpretative Phenomenological Analysis revealed three main themes of importance; response to difficult emotions, impact on self and intergroup processes. The clinical implications and areas for future research are discussed alongside methodological considerations and limitations. Chapter three is a reflective account of the emotional experience of conducting the research and considers the impact of the chosen methodology, parallels of experience between the researcher and the participants and the impact of the research process on future clinical practice.

Neurite size and morphology are key determinants of the functional properties of neurons. In this thesis, it is described for the first time the expression of APRIL (A Proliferation-Inducing Ligand, TNFSF13) in the nervous system. APRIL is a member of the tumour necrosis factor superfamily and one of its receptors BCMA (B-Cell Maturation Antigen, TNFRSF17) are coexpressed in pyramidal neurons throughout the fetal and postnatal mouse hippocampus. The effect of APRIL on axon elongation is inhibited by the expression of a truncated BCMA receptor in the neurons, suggesting that BCMA mediates this effect. APRIL promotes rapid phosphorylation of ERK1/2, Akt and GSK-3β in cultured pyramidal neurons, and pharmacological inhibition of either MEK1/2 or PI3K, upstream activators of ERK1/2 and Akt/GSK-3β signalling, respectively, completely inhibits the axon growth-promoting action of APRIL. These findings reveal that APRIL selectively enhances axon growth from developing hippocampal pyramidal neurons by a mechanism that depends on BCMA and activation of ERK1/2 and Akt/GSK-3β signalling. In this thesis, it is also shown that GDF-5 (growth-differentiation factor 5), a member of the transforming growth factor-β superfamily with a wellcharacterized role in limb morphogenesis, is a key regulator of the growth and elaboration of pyramidal neuron dendrites in the developing hippocampus. Pyramidal neurons co-express GDF-5 and its preferred receptors bone morphogenetic protein receptor-IB and bone morphogenetic protein receptor-II during development. In culture, GDF-5 substantially increased dendrite, but not axon, elongation from these neurons by a mechanism that depends activation of Smads1/5/8 and upregulation of the Hes5 transcription factor. In vivo, the apical and basal dendritic arbors of pyramidal neurons throughout the hippocampus were very markedly stunted in both homozygous and heterozygous Gdf-5 null mutants, indicating that dendrite size and complexity are exquisitely sensitive to the level of endogenous GDF-5 synthesis

The aim of the research presented in this Thesis was twofold; firstly to further understand the role of Foxp1 in the development of striatal medium spiny neurons (MSN) and secondly its role the adult brain. Understanding the role of Foxp1 in MSN development may allow more accurate in vitro protocols to be generated for use in directing renewable cell sources for use in cell replacement therapies for diseases such as Huntington’s disease (HD). Additionally, its functional role in MSN development may not be exclusive, and thus have a more generalised role transferable to other neuronal processes. Thus what is learnt about its function can possibly be applied to cell transplantation protocols in general, as well as be useful in the drug discovery field. In mice, the transcription factors (TF) Foxp1 and Mef2c were shown to be significantly up-regulated during peak MNS development (embryonic day (E) E12-16) in a genetic screen carried out in the host lab in 2004. Consequently the majority of work in this thesis was focused on the characterisation of the most significantly up-regulated gene, Foxp1. Experiments initially focused on a Foxp1 knock out (KO) line, both in vitro and following transplantation into the quinolinic acid (QA) lesioned adult mouse brain. Additionally, owing to embryonic lethality at E14, a conditional Foxp1 KO (CKO) line was also developed to study the effects of the loss of Foxp1 in the adult brain with a focus on the loss of Foxp1 from the cortex. Owing to lethality at E9 a Mef2c CKO line was also developed and initial in vitro findings from this line are presented in Appendix 8 of this Thesis. Chapter 3 characterised the wild type (WT) expression pattern of FOXP1 from E10 to P7 through the co-localisation of FOXP1 with the established MSN markers CTIP2 and DARPP-32. In vitro characterisation of cultures generated from striate of Foxp1-/- mice showed a decrease in the number of CTIP2 and DARPP-32 positive cells compared to littermate controls but that there were no differences in the proliferation of these cells between groups. Finally, results from immunohistochemistry on selected striatal KO brain sections suggested that Foxp1 may function downstream of Ascl1 and Gsh2 in striatal development. In Chapter 4 E14 or E12 striatal tissue from all three genotypes was grafted into an adult QA-lesion mouse model. Such experiments allowed striatal neurons from Foxp1-/- mice to survive for much longer periods than was possible in vitro and provided them with the opportunity to make some of their normal connections. Results showed that there were fewer DARPP-32 positive cells in grafts from Foxp1-/-compared to controls, as with in Chapter 3. Moreover, FOXP1 was identified as a novel maker of P-zones in grafts derived from whole ganglionic eminence. Chapter 5 addressed the generation of a Foxp1 CKO mouse model under the control of an hGFAP-Cre line (Foxp1 CKO). Histology showed that FOXP1 was lost from all layers of the cortex, but expression was maintained in the striatum. Mice appeared hyperactive in the home cage compared to littermate controls, and as mutations in FOXP1 have been associated with autism spectrum disorders, of which ADHD falls under, led to directed behavioural analysis targeting the symptoms of ADHD. Analysis revealed Foxp1 CKO mice were significantly hyperactive (activity boxe and open-field data) and inattentive (5 choice serial reaction time task) but had no anxiety problems (elevated plus maze and marble burying task). These symptoms were shown to be reduced following the administration of atomoxetine, a drug prescirbed to patients with ADHD. Results collectively suggested that the Foxp1 CKO line is a new mouse model of ADHD.

I describe the process of preparing cohorts of individuals with two paediatric onset paroxysmal disorders – hyperekplexia and juvenile myoclonic epilepsy – for second generation sequencing. This involves: i) listening to the individual; ii) identifying subgroups; iii) using non-­‐core features to create subgroups; iv) and assessing the importance of copy number variation. Using focus groups and an interpretative phenomenological approach clinicians and people with epilepsy produced 398 questions focused on epilepsy treatment. The most important themes for the professionals were – teatment pogrammes or non-­‐epileptic attack disorder and concerns about side effectsinutero.For patients cognitive drug side effects and managing the consequences of drug side effects were most important. Studying ninety-­‐seven individuals with hyperekplexia confirmed that all gene-­‐positive cases present in the neonatal period and that clonazepam is the treatment of choice (95% found it efficacious). Patients with SLC6A5 and GLRB mutations were more likely to have developmental delay (RR1.5 p<0.01; RR1.9 p<0.03) than those with GLRA1 mutations; 92% of GLRB cases reported a mild to severe delay in speech acquisition. Juvenile myoclonic epilepsy is challenging to subdivide based on seizure and EEG features. The neuropsychological profile of limited number of patients 39) as examined in great detail including tests Q WAIS), emory TYM,WMS),executive function (BADS, DKEFS), affect (HADS). TYM was as sensitive as a full WMS for identifying cognitive errors and the zoo map and key search tests were performed particularly poorly. Personality profiling (EPQ-­‐BV) identifies the cohort as having high levels of neurotic and introvert traits. Three atypical ‘hyperekplexia’ cases had alternative diagnoses suggested by copy number analysis. The juvenile myoclonic epilepsy patients had an 8% frequency of recognised pathogenic CNVs– but no recurrent variants were identified.A number of non-­‐epilepsy related findings were identified including a potentially preventable cause of SUDEP.

The extracellular calcium sensing receptor (CaSR) is a G-protein coupled receptor that monitors extracellular, free ionized-calcium levels ([Ca2+]o) in organs that maintain systemic [Ca2+]o homeostasis. CaSR is also expressed in the nervous system, where this lab recently found that it regulates the axonal growth and branching of sympathetic neurons and the dendritic growth of hippocampal pyramidal neurons during development. Other labs have subsequently shown that CaSR regulates presynaptic physiology in response to activity induced synaptic fluctuations in [Ca2+]o. Although individuals with CaSR mutations may present with seizures from childhood, the developmental significance of synaptic CaSR has not been investigated. This thesis reports the developmental regulation of Casr mRNA expression in multiple brain regions of mice. A previously unreported peak in hippocampal Casr mRNA expression at postnatal day 14 led to the testing of the hypothesis that CaSR may play a role in synapse formation. A novel in vitro culture method was developed to circumvent perinatal lethality in the available in vivo conditional CaSR knockout model. However, this study, using both pharmacological and genetic methods, has been unable to find any evidence to suggest that CaSR regulates synaptogenesis in vitro. This thesis also reports an effect of [Ca2+]o on neurite outgrowth from sympathetic neural cells early in their development. However no deficit in proximal sympathetic axon growth is observed in CaSR knockout embryos in vivo. Novel findings suggest that in 2.3 mM Ca2+o, elevated wild type CaSR expression is necessary and sufficient for CaSR-promoted axonal growth in late embryonic sympathetic neuron cultures. This effect is not seen in low [Ca2+]o medium or cells expressing inactivated CaSR mutants, but is shown to require ERK1/2 activation, a portion of the C-terminal domain of CaSR, and is regulated by a PKC phosphorylation site contained therein.

Rett syndrome (RTT) is a neurodevelopmental disorder that is caused by mutations in the X-linked gene MECP2 and results in cognitive impairment, epilepsy and motor dysfunction. Deletion or silencing of Mecp2 in the brain of mice recapitulates many of the main phenotypes of the disorder and has been fundamental in understanding the actions of MeCP2 although the precise molecular function remains unknown. MeCP2 is classically thought to have a role in repressing gene transcription through recruitment of histone deacetylase proteins. Studies have also shown that Mecp2 can be modified posttranslationally in response to neuronal activity. The aim of this thesis was to investigate the activity-dependent alterations in MeCP2 and the association this has with levels of acetylated histone proteins, a marker of active gene transcription thus gaining a better insight into how neuronal activity affects the function of MeCP2. Furthermore at the network level, a second objective was to characterise the effects loss of functional MeCP2 has on the regulation of network circuitry in the brain and in particular the development of epileptiform activities. To study this I focussed on the hippocampus in wild-type and Mecp2 mutant mice and in vivo administered the convulsant drug kainic acid (25mg/kg; IP) followed by seizure scoring and in vitro by application of various epileptogenic agents (kainic acid, bicuculline and 4-aminopyridine) to acute hippocampal slices. Having characterised the network properties, I then quantified protein alterations in phosphorylation of Mecp2, acetylated histone H3 and H4 and immediate early genes, c-Fos and Egr-1 in the hippocampus using western blot and quantitative immunohistochemistry techniques. Based on a modified seizure scale (eight stages with lower being less severe), administration of kainic acid in vivo to Mecp2-deficient male mice resulted in a higher seizure score (mean = 6 ± 0.7 vs. 4 ± 0.2 units in wild-type) and more rapid onset (77% of mice show seizures after 10 minutes compared to 5% of wild-type mice). Field recording data collected in vitro following application of kainic acid to hippocampal slice from Mecp2-deficient mice show a significant increase in gamma power oscillation (1059 ± 379µV2) compared to slices from WT mice (287 ± 178µV2) which had a lower mean power. Application of bicuculline revealed hippocampal slices from Mecp2-deficient mice had increased frequency of spontaneous epileptiform field events (1µM and 3µM bicuculline) and elevated duration of spontaneous and evoked epileptiform field events (10µM bicuculline). Similarly, 4-aminopyridine (4-AP) administration to hippocampal slices resulted in Mecp2-deficient mice displaying increased frequency of spontaneous field events (50µM 4-AP) and epileptic ictal-like events (88% of slices from Mecp2stop/y mice displayed these events compared to 43% of slices from WT mice). Furthermore there was an increase in spontaneous and evoked field events following application of 30µM and 10µM 4-AP. Western blot experiments using hippocampal extracts from WT and Mecp2-deficient male mice treated with the convulsant drug kainic acid or saline (vehicle control) revealed Mecp2 is highly phosphorylated at serine 421 (3.4 ± 0.5 fold, p< 0.01) upon induction of neuronal activity compared to saline controls but there was no change in histone H3 or H4 acetylated proteins. A complementary quantitative immunohistochemistry approach was used to assess variations in histone H3 or H4 acetylated proteins at the single cell level from heterozygous female mice (displaying a mosaic expression of Mecp2) treated with kainic acid or saline. These results revealed there was no difference in the levels of either acetylated histone H3 of H4 protein between Mecp2 positive and negative nuclei. However there was a clear cell-autonomous effect in terms of a 5% reduction in the nuclear volume of Mecp2-deficient cells. Quantification of immediate early gene signal in Mecp2+/- heterozygous female mice treated with kainic acid or saline using the same immunohistochemistry method showed there was no difference in the distribution of c-Fos intensities between Mecp2 positive and negative nuclei following any treatment. However there was a greater proportion of Mecp2-deficient nuclei (~20%) expressing c-Fos under saline control conditions and following neuronal activity. Furthermore there was a reduction in the percentage of Mecp2 negative nuclei in the top 25% of Egr-1 intensities in the CA1 following three hours of neuronal activity (33.5 ± 2.3% for Mecp2 negative nuclei and 19.1 ± 1.7% for Mecp2 positive nuclei). In summary my results show at the network level there is a reduction in seizure threshold and increase power of gamma oscillations in the hippocampus of Mecp2-deficient mice which could lead to a state of network hyperexcitability and switch activities from physiological oscillatory rhythms to more pathological ones. An imbalance in inhibitory neuron regulation could partially contribute to alterations in network excitability to overall promote epileptogenesis. At the cellular level I report that Mecp2 can become phosphorylated following induction of neuronal activity but this is not associated with alterations in global histone acetylation. Nonetheless Mecp2-deficient cells display a reduction in nuclear volume and have alterations in c-Fos and Egr-1 levels following induction of neuronal activity. Overall my data contribute to the understanding of how the presence or absence of MeCP2 affects network excitability and how in turn neuronal excitability affects MeCP2 phosphorylation, histone acetylation and the activation of immediate early genes.