Effects of Ketamine and Risperidone on Cognition

This study is a continuation from a previous study (P1V-SCH-CT01-07). The overall aim of the 2 studies is to identify and validate potential biomarker tasks that may be used to provide early indications into the use of new treatments for schizophrenia. The studies are considering two potential models for schizophrenia in healthy volunteers, the first model looks at high versus average schizotypy, schizotypy being a personality trait. The second model, explored in this study, is a ketamine infusion. Healthy volunteers will be identified through advertising and will initially be asked to complete an online questionnaire.Suitability for the next stage of the study will be based on the responses to the online questionnaire. Telephone interviews will then be conducted to assess suitability for screening.Screening visits will then be carried out in which a full medical and lab screening is undertaken. participants will also complete a number of psychiatric questionnaires and interviews. If participants remain suitable they will be invited to an assessment day in which they will be randomised to one of four study medication arms. Participants will then complete the biomarker tasks followed by questionnaires, rating scales and interviews. Patients with schizophrenia will form the 5th study arm and will not receive medication. They will complete the biomarkers in the same way as healthy volunteers.87 participants are planned, 72 healthy volunteers, 15 patients with schizophrenia. This study does not test any investigational medicinal product (IMP) so any ethical issues that are associated with introducing a participant to a study drug are not applicable in this study. Ketamine is already a widely used anaesthetic agent but when given at sub-anaesthetic doses is a useful tool for modelling schizophrenia psychosis. The current study aims to assess the sensitivity of a battery of biomarker tasks (biomarkers are measures of processes that go wrong in illnesses and that contribute to symptoms) to the cognitive deficits induced by ketamine. It may in future be possible to evaluate the effects of novel treatment for schizophrenia in healthy volunteers using this model, which would then potentially provide a rapid indication of the potential efficacy of candidate compounds at an early phase of drug development . The study will provide information about the sensitivity of the biomarker tasks in detecting the effects of the pharmacological treatments for schizophrenia in healthy volunteers.