<p>Allosteric modulators are a newly emerging concept in the field of drug discovery which have shown remarkable success in their ability to alter G-protein coupled receptor (GPCR) activity in a precise and subtle manner. A GPCR of particular interest for allosteric targeting is the dopamine D2 receptor. This receptor has repeatedly been implicated in the etiology of complex neurological and neuropsychiatric disorders including Parkinson’s disease and schizophrenia. Previous studies from our lab have effectively developed allosteric modulators targeting the D2 receptor based on the pharmacophore of the endogenous tripeptide L-prolyl-L-leucyl-glycinamide (PLG). PLG and its potent peptidomimetics, particularly 3(R)-[(2(S)-pyrrolidinylcarbonyl)amino]-2-oxo-1-pyrrolidineacetamide (PAOPA) (PCT/CA2011/000968), have shown robust preclinical efficacy in treating models of Parkinson’s disease, depression, tardive dyskinesia and schizophrenia. These ligands modulate agonist binding to the D2 receptor in a biphasic manner, although further information on their mechanisms of action are currently unknown. Therefore, the overarching objective of this thesis was to enhance our knowledge on the mechanisms of action of the promising D2 allosteric ligands PLG and PAOPA. Results of the studies presented here show PAOPA to cause significant upregulation of D2 regulatory proteins and downstream signaling kinases, as well as cause an increase in D2 internalization. Additionally, the PLG allosteric binding site was narrowed down to be localized between transmembrane domains 5 and 6 on the D2 receptor. The collection of work presented here enhance our understanding of the mechanisms of action of the potentially therapeutic D2 allosteric ligands PLG and PAOPA, progressing them closer to helping clinically affected populations. The findings of these studies prove globally significant as they highlight the diverse cellular pathways which could be affected by allosteric modulators, and bring to light the importance of studying these candidate ligands for eventual improvements in the treatment of human health.</p> / Doctor of Philosophy (Medical Science)

Introduction: The volume of antipsychotic medications prescribed to children and adolescents has risen sharply since second generation antipsychotics, also referred to as atypical antipsychotics, were introduced in the 1990’s. The concern surrounding the expanded use of antipsychotics was that the medications have significant adverse metabolic side effects and they were often prescribed to treat conditions in young children for which they have not been proven to be safe and effective. While it is not unlawful for health care providers to prescribe medications for uses beyond which they have been approved by the United States Food and Drug Administration, the lack of empirical evidence guiding much of the antipsychotic use in children had professional pediatric medical groups and policy makers concerned for the well-being of children receiving the medications. Several states, including Pennsylvania, enacted prior authorization policies in an attempt to restrict prescribing to children where a medical need has been established. However, the impact of the policies is largely unknown since published data on the topic is sparse. Methods: This retrospective, medical claims-based cohort study, used de-identified administrative Medicaid data from January 2008 to December 2010 to investigate the impact of Pennsylvania’s September 2008 antipsychotic prior authorization policy on antipsychotic prescribing prevalence in children targeted by the policy. Descriptive methods and segmented regression of the interrupted time series were used to assess the effects of the policy on monthly antipsychotic prescribing prevalence. A difference-in-difference analysis compared Pennsylvania’s prescribing to Ohio, a geographically proximate and demographically similar state without a prior authorization policy; and Delaware, a state that enacted a policy 3 years prior to Pennsylvania. The potential for compensatory prescribing was assessed by reporting the prevalence of other psychotropic medications over the study period. Results: An average of 99,074 Pennsylvania Medicaid enrollees ages 0-6 were identified as meeting the study criteria annually from 2008-10. Immediately following the policy intervention, an abrupt, significant reduction in monthly prescriptions of antipsychotics was observed (-51 prescriptions per 100,000; p=0.0052) and sustained over the observation period. The proportion of children filling prescriptions for antipsychotics dropped approximately 46% and the average number of antipsychotic prescriptions filled per month was reduced by 53% in 2010 compared to 2008. In Ohio, a state without such a policy, the proportion of children receiving an antipsychotic increased nearly 10% in 2010 compared to 2008 and the average number of monthly prescriptions increased 30%. Reductions in antipsychotic prescribing in Delaware, a state that had its antipsychotic policy in place since 2005, were comparable to Pennsylvania. There was no evidence that non-antipsychotic psychotropic medications were prescribed in place of the medications restricted by the policy. Conclusions: Pennsylvania’s 2008 prior authorization policy was associated with a significant decrease in annual and monthly antipsychotic prescribing prevalence in Medicaid-insured children targeted by the policy, those ages 0-6 years of age. Reductions in most other psychotropics was also observed, indicating changes in prescribing behavior may have extended beyond antipsychotics. While this analysis suggests the policy may have achieved its primary aim of reducing antipsychotic prescribing, more research is needed to better understand the complex array of factors influencing provider behavior and to explore potential unintended consequences of the policy. / Public Health

Schizophrenia is a severe mental disorder that can manifest in various ways and is often characterized by the appearance of positive symptoms (hallucinations, delusions), negative symptoms (social and attention impairment) and cognitive dysfunction (thought disorders, memory and executive function impairments). Traditional treatment methodologies involve blocking the dopamine receptor by binding to the same site as dopamine. These treatments are largely inadequate and lead to an array of adverse side effects. Side effects include weight gain, diabetes, and movement disorders; which critically limit the therapeutic value of antipsychotic drug treatment. Limited symptom control and severe adverse effects have led to poor drug adherence and a deprived quality of life for patients suffering from schizophrenia. The complex etiology of schizophrenia combined with a lack of effective translational models and tests to represent and assess the illness have hindered drug development. Evidently, there is a strong demand for a new generation of pharmaceuticals and an improved translational pipeline for the treatment of schizophrenia. The collection of studies presented here contribute to the advancement of translational tools for drug discovery, the establishment of pre-clinical models to embody the various symptoms, and the development of a novel drug candidate for schizophrenia. Allosteric modulation of G-protein coupled receptors is evolving as a new wave of therapy with promising implications for various CNS disorders. Allosteric compounds regulate binding without blocking the receptor. PAOPA, a dopamine D2 receptor allosteric modulator, prevents and treats schizophrenia-like symptoms in pre-clinical animal models of schizophrenia with no apparent adverse effects. The studies outlined in this thesis further categorize PAOPA as a novel therapeutic candidate for schizophrenia. Moreover, the findings presented here provide further insight into the potential therapeutic mechanism of action of PAOPA and set the foundation for the development of a new generation of antipsychotic drugs. These studies constitute an innovative approach to expanding research in the field of drug development for schizophrenia. / Thesis / Doctor of Philosophy (PhD)

Schizophrenia is a debilitating neuropsychiatric disorder that affects approximately one percent of the global population. Aberrant N-methyl-D-aspartate receptors and endoplasmic reticulum stress have been implicated in the pathogenesis of schizophrenia. Despite a century of extensive research, outcomes from best-practice treatments remain dismal. Lurasidone hydrochloride is a novel atypical antipsychotic drug with a unique receptor binding profile that can potentially treat the heterogeneous symptomology of schizophrenia. However, discrepancies in experimental design (i.e. animal models used, symptoms assessed etc.) have yielded conflicting results surrounding the procognitive and antidepressant properties of lurasidone. Furthermore, the limited aqueous solubility of lurasidone poses a considerable challenge for improving antipsychotic drug delivery to the brain and limiting the prevalence of adverse side effects. These obstacles coupled with the elusive pathophysiology of schizophrenia and its incurable nature, highlight the importance of investigating novel therapeutic targets and their underlying mechanisms to improve treatment and enhance the quality of life of patients with schizophrenia. This thesis sought to accomplish three primary objectives: (1) validate the behavioural efficacy of lurasidone hydrochloride; (2) investigate the role of mesencephalic astrocyte-derived neurotrophic factor as a potential therapeutic target of lurasidone; and (3) evaluate the therapeutic potential of intranasal lurasidone administration as a novel method for antipsychotic drug delivery. The data presented within this thesis suggest that repeated lurasidone treatment may be effective at treating the positive, negative, and cognitive symptoms of schizophrenia, but not sensorimotor gating deficits. Furthermore, sub-chronic lurasidone treatment in rats significantly increased the relative expression of mesencephalic astrocyte-derived neurotrophic factor in the rat prefrontal cortex, a primary site of impairment observed in schizophrenia. Lastly, we conclude that lurasidone administered via the nasal route using a novel poly(oligo ethylene glycol methacrylate)-based nanogel formulation required four times less drug to achieve a therapeutic response comparable to traditional intraperitoneal routes. The findings presented within this thesis suggest that lurasidone might be a favourable atypical antipsychotic drug that exerts its therapeutic effects through the modulation of neurotrophic factor expression in the brain regions affected by schizophrenia. This thesis offers new insight that can help guide future studies toward improving the prognosis of patients suffering from schizophrenia. / Thesis / Master of Science (MSc)

No / Rationale: Weight gain caused by some antipsychotics is not only confined to adults but can also adversely affect both children and adolescents. Indeed, olanzapine and risperidone have been associated with extreme weight gain in adolescents even greater than that reported in adults. We have recently shown substantial weight gain in adult female rats following treatment with olanzapine and risperidone but not ziprasidone. Objectives: The aim of the present study was to compare the effects of several antipsychotics on weight gain and reproductive function in juvenile (aged 7 weeks) female hooded Lister rats. Methods: Olanzapine (4 mg/kg), risperidone (0.5 mg/kg), ziprasidone (2.5 mg/kg), sulpiride (10 mg/kg), haloperidol (0.5 mg/kg) or vehicle was administered i.p. once per day for 21 days. Body weight, food and water intake were measured daily, in addition to the determination of stage of the oestrous cycle. Results: Sub-chronic administration of olanzapine, risperidone, sulpiride and haloperidol, but not ziprasidone, significantly increased body weight compared to vehicle-treated animals during weeks 1-3. Sulpiride significantly increased food and water intake. Significantly increased percentage intra-abdominal fat weight was observed in olanzapine, risperidone, sulpiride and haloperidol, but not ziprasidone-treated animals. Marked disruption of the oestrous cycle was observed in all but the ziprasidone-treated group, which continued to have regular 4-day oestrous cycles. Conclusions: Weight gain observed in these juvenile animals was 1.5-2 times greater than that previously observed in adult rats. These findings have important implications for the use of antipsychotics in children and adolescent patients.

Bakgrund: Schizofreni är en kronisk sjukdom som kan resultera i förkortad livslängd, utanförskap, förhöjd suicidrisk och orsakar lidande för patienter och anhöriga. Dessutom innebär sjukdomen höga kostnader för samhället. Antipsykotiska läkemedel är en central del av behandlingen och nödvändig för återhämtning och att minska risk för recidiv. Bristande sjukdomsinsikt, otillräcklig effekt och svåra biverkningar kan påverka följsamheten. Psykiatrisjuksköterskan kan genom personcentrerad vård stödja patienter till förbättrad hälsa och minskat lidande. Syfte: Syftet var att beskriva upplevelser av behandling med antipsykotiska läkemedel  hos patienter med diagnosen schizofreni.   Metod: Litteraturöversikt med systematisk ansats valdes som metod. Sökningen genomfördes i databaserna CINAHL, PubMed och PsycInfo. Resultatet analyserades med hjälp av Thomas och Hardens tematiska syntes. Resultat: Resultatet baserades på analys av femton originalartiklar som berörde patienter med schizofreni och deras upplevelser av antipsykotisk läkemedelsbehandling. Teman som framkom var; Upplevelser av kontrollförlust och trygghet, Upplevelser av en förändrad vardag, samt Upplevelser av delaktighet. Slutsats: Patienter med schizofreni upplevde behandling med antipsykotiska läkemedel både som en hjälp och förlust med stor påverkan på daglig funktion och relationer. Patienterna beskrev svårigheter att vara delaktiga i sin behandling och vårdalliansen som central. Att finna en fungerande medicinering var en komplex process som förutsatte stöd från anhöriga och vårdpersonal. / Background: Schizophrenia is a chronic disease that can result in shortened lifespan, isolation, increased suicide risk and causes suffering for patients and relatives. In addition, the disease entails high costs for society. Antipsychotic drugs are a central part  of treatment and necessary for recovery and to reduce the risk of relapse. Lack  of insight, insufficient effect and severe side effects can affect compliance. Through person-centred care, the psychiatric nurse can support patients to improve their health and reduce suffering. Aim: The aim was to describe patients' experiences of treatment with antipsychotic  drugs in schizophrenia Methods: A literature review with a systematic approach was used as method. The search was undertaken in the databases CINAHL, PubMed and PsycInfo. The result was analysed using Thomas and Hardens thematic synthesis. Results: The result was based on the analysis of fifteen primary research articles concerning patients with schizophrenia and their experiences of antipsychotic drug treatment. Themes that emerged where; Experiences of losing control and feeling safe, Experiences of changes in everyday life, as well as Experiences of participation. Conclusions: Patients with schizophrenia experienced treatment with antipsychotic drugs both as a help and a loss with a major impact on daily functioning and relationships. The patients described difficulties in being involved in their treatment and the therapeutic alliance as central. To find a stable medication was a complex process that required support from relatives and healthcare professionals.

Thesis (DMed (Psychiatry))--University of Stellenbosch, 2007. / This study reports on the effect of seminar education by studying changes in knowledge, attitude and behaviour to haloperidol prescribing patterns of psychiatrists who In summary, this study demonstrated a direct relationship between seminar attendance and changes to selected minimum effective haloperidol dose and duration of treatment. However, seminar attendance did not appear to be a significant factor in changes to antipsychotic class used for treatment and changes in optimal effective haloperidol dose: rather a change in the level of “background” knowledge of participants was most likely responsible. This study also found individual participant characteristic differences in those who did change treatment duration and minimum effective dose. In conclusion, this study showed that the successful integration of international treatment recommendations into daily psychiatric practise could be facilitated by the use of appropriate educational seminars. Not all attendees benefit i.e. “learn”, but those needing to “learn” most do - i.e. those who need to change their prescribing habits most to meet internationally accepted guidelines. The peer exposure provided allows a format for informed discussion and the practise of evidence-based medicine. The judicious use of such seminars should result in better treatment options and outcomes for patients.attended evidence-based schizophrenia seminars presented by the Lundbeck Institute in Denmark. The objectives of the study were two-fold. Firstly, it set out to determine whether changes actually occurred in the post-seminar haloperidol prescribing behaviour of participants. This was done by analysing changes in choice of optimal haloperidol dose (both in acute treatment i.e. most effective dose and maintenance treatment i.e. minimum effective dose), selected duration of treatment (for first- and multi-episode schizophrenia patients) and drug-class used (conventional versus new generation antipsychotic). The study then investigated whether these changes (if they occurred) could be ascribed wholly or in part to the effect of schizophrenia seminar attendance, or whether other factors e.g. scientific progress over time in understanding schizophrenia and its treatment (“background” knowledge) and differences between participant datasets studied (only paired pre- and post-seminar data were used in this study) also played a role. Secondly, it attempted to identify factors predictive of seminar participants changing their haloperidol prescribing behaviour post-seminar i.e. what were the factors that predisposed some attendees to change their prescribing behaviour? This was done by analysing the effect that pre-seminar prescribing behaviour, participant nationality, patient caseload, work experience and workplace environment had on post-seminar behaviour. Results show that changes did occur in post-seminar haloperidol prescribing behaviour, but that they were not always due to an effect of seminar attendance. Only the changes in the minimum effective haloperidol dose and duration of treatment for first- and multi-episode schizophrenia patients could validly be ascribed to the effects of schizophrenia seminar attendance. Furthermore, multivariate analysis of the factors relating to these changes found that a participant was most likely to change their selected minimum effective haloperidol dose to be more in line with internationally accepted standards if they i) selected above the target dose pre-seminar, ii) had a relatively low caseload comprised mainly of schizophrenia patients and iii) came from either Greece, Germany, Britain, Spain, Italy or some other Eastern European country. The single most important factor related to changes in duration of treatment was found to be pre-seminar behaviour: respondents below the recommended duration of treatment increased their duration of treatment significantly.

Background: The main aim of the studies in this thesis is to provide insights into the neonatal phencyclidine (PCP) induced deficits in male and female rats as a neurodevelopmental animal model of schizophrenia. Methods: Both male and female rats were treated with neonatal PCP on postnatal days (PNDs) 7,9 and 11 or vehicle, followed by weaning on PND 21-22. The rats were then tested in behavioural paradigms such as novel object recognition, spatial memory and social interaction in their adolescent and adult stages and were also tested with acute treatment of typical and atypical antipsychotic agents. Results: Neonatal PCP treatment (10 &amp; 20 mg/kg in males and 10 mg/kg in females; once a day for 3 days on PND 7,9 and 11) caused novel object recognition and spatial memory impairment in male and female rats both in the adolescent (PND35-56) and in the adult stages (PND&gt;56) (chapter 2) and robust deficits in social interaction behaviours in the adolescent stage. The SI deficits were observed in adulthood in female but not in male rats thereby establishing a sex-specific social behavioural deficit (chapter 3). The object memory and social interaction deficits induced by neonatal PCP treatment were reversed following acute risperidone but not haloperidol. Finally, the temporal profile of this treatment regime was investigated and the male and female animals were tested on PND 190 and PND 365. The animals did not have any challenge dose of PCP during their testing stage. The result showed that there was significant deficit in object and spatial recognition memory in both male and female animals at both time points, thereby establishing enduring deficits. Conclusion: Given the heterogeneity of the schizophrenic disorder and its complex aetiology, it is understandably difficult to find animal models that completely mimic most or all of the symptoms associated with the disorder. However, data from the studies in this thesis support the use of neonatal PCP as a valid animal model of cognitive and negative symptoms, and explores the effect of antipsychotics in understanding the model. Also, in light of the efficacy of neonatal PCP to produce robust object, spatial memory and social interaction deficits in rats, it appears that this model may be a useful tool to investigate the potential of novel therapeutic candidates that may help improve therapy and understand the illness.

INTRODUÇÃO: Re-hospitalização é uma medida de desfecho reconhecida e utilizada em estudos para acessar prevenção de recaída que é considerada um dos principais indicadores de efetividade de um antipsicótico. Foi testada a hipótese que a clozapina seria superior aos demais antipsicóticos na prevenção de re-hospitalizações em pacientes com esquizofrenia que receberam alta do Instituto de Psiquiatria do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo entre 1 de dezembro de 1997 e 31 de dezembro de 2004. MÉTODOS: Este foi um estudo observacional de coorte, retrospectivo, desenhado para avaliar o tempo de re-hospitalização de pacientes que receberam alta em uso de antipsicóticos convencionais ou antipsicóticos de segunda geração, exceto clozapina ou clozapina, por um período de três anos. A análise de sobrevivência foi estimada pela fórmula produtolimite de Kaplan-Meier. Foi utilizado o modelo de regressão de Cox para identificar fatores associados à re-hospitalização. RESULTADOS: Dos 464 pacientes com esquizofrenia que receberam alta no período do estudo, foram selecionados 242 pacientes. A re-hospitalização foi observada em 12 (17%) pacientes em uso de antipsicóticos convencionais, 27 (24%) pacientes em uso de antipsicóticos de segunda geração, exceto clozapina, e nove (15%) pacientes em uso de clozapina. As análises de sobrevivência demonstraram uma diferença estatisticamente significante entre os três grupos e entre os grupos de antipsicóticos de segunda geração e clozapina. As variáveis clínico-demográficas não foram associadas à re-hospitalização. CONCLUSÕES: O grupo de pacientes que recebeu clozapina apresentou menor taxa de re-hospitalização do que os demais grupos. As diferenças entre tempo de rehospitalização foram estatisticamente significantes entre os três grupos e entre os grupos de pacientes que receberam clozapina e antipsicóticos de segunda geração. Os resultados são limitados pela heterogeneidade da gravidade do transtorno entre os grupos. / INTRODUCTION: An important outcome parameter of drug effectiveness in schizophrenia is relapse prevention which can be reliably measured by time to rehospitalization. We tested the hypothesis that clozapine was superior to other antipsychotics in preventing rehospitalization in patients with schizophrenia discharged from the Institute of Psychiatry. METHODS: This is a retrospective observational cohort study designed to evaluate rehospitalization rates of patients with schizophrenia discharged from the Institute of Psychiatry of the Hospital das Clínicas of the University of Sao Paulo between Dec 1, 1997 and Dec 31, 2004 on a regimen of either conventional antipsychotics or nonclozapine second generation antipsychotics or clozapine during a three years follow-up. Risk factors associated with rehospitalization were examined by Cox regression model and survival curves were estimated by the product-limit formula (Kaplan-Meier). RESULTS: Of the 464 patients with schizophrenia discharged from hospital 242 met criteria to enter the study. They were followed at IPq outpatient clinic for three years. Of these 12 (17%) patients discharged in use of conventional antipsychotic, 27 (24%) in use of non-clozapine second generation antipsychotic, and nine (15%) in use of clozapine were rehospitalized. Survival analysis demonstrated a significant difference in timeto-rehospitalization between groups and between clozapine and second generation antipsychotics groups. CONCLUSIONS: Patients with clozapine were less rehospitalized than the others groups. The differences in time to rehospitalization were statistically significant between the three groups and between clozapine and nonclozapine second generation antipsychotics groups. Results were limited due to the heterogeneity of severity of illness between groups.

Schizophrenia is a severe mental disorder affecting ~1% of world population. Two G protein coupled receptors (GPCRs): Gi-coupled dopamine D2 receptor (D2R), and Gq-coupled serotonin 2A receptor (2AR), are targeted by the typical and atypical antipsychotic drugs to treat schizophrenia. These two receptors have been shown to co-localize in brain regions relevant to schizophrenia, including the ventral tegmental area (VTA), striatum, and prefrontal cortex (PFC). Studies in our lab characterized the integrated signaling of the D2R-2AR heteromer and found that both the Gi activity of D2R and the Gq activity of 2AR were potentiated in response to dopamine (DA) and serotonin (5-HT), whereas the potency of the typical antipsychotic drug (APD) haloperidol antagonizing Gi and Gq signaling was also enhanced. Using a peptide mimicking the transmembrane (TM) domain 5 of D2R, we showed disruption of the formation and function of the D2R-2AR heteromer in heterologous systems and ex vivo brain slices. Our functional and mutagenesis data suggested that D2R and 2AR heteromerize though a symmetric TM5,6-TM5,6 interface, and a network of Pi-Pi stacking interaction among eight conserved aromatic residues of D2R and 2AR may underlie the mechanism for the functional cross-talk between D2R and 2AR. Based on these results, we built a structural model for the D2R-2AR heteromer recapitulating its functional cross-talk characteristics. We are presently pursuing behavioral experiments to investigate the effectiveness of antipsychotic drugs on the function of the D2R-2AR heteromer in animal models of psychosis. Our overall study shows a dual role of the D2R-2AR heteromer in schizophrenia-associated psychosis and sheds light on the development of future therapeutic drugs for schizophrenia and other psychotic diseases.