At-risk mental state and prediction

Introduction Recently, the area of ‘prodromal’ research in schizophrenia and related disorders has grown considerably. From initial retrospective studies of this phase, dating back to the early twentieth century, the last decade of the century has seen the beginning and expansion of prospective studies aiming to identify the earliest manifestations of psychotic illnesses. From identification of these prodromal or ‘ultra-high-risk’ (UHR) individuals, the area has also developed to include intervention studies aiming to prevent, delay or ameliorate the onset of a full-blown psychotic disorder and to investigate underlying processes that cause or contribute to the onset. This chapter discusses the rationale behind this field of research, reviews the literature on the detection of prodromal or UHR individuals, summarizes the findings on the prediction of psychosis in these people and provides an up-to-date overview of progress and future directions in the field. We start by briefly reviewing the background. Background: the prodrome of psychotic disorders The fact that psychotic disorders, such as schizophrenia, begin with a prodromal phase prior to the onset of frank psychotic symptoms has been known since the first descriptions of the illness were documented (Conrad, 1958; Kraepelin, 1919). Although there is great variability between patients in how their prodromes manifest, certain symptoms and signs have been frequently described. These include depressed mood, anxiety, irritability and aggressive behaviour, suicidal ideation and attempts, and substance use. The most commonly occurring prodromal symptoms, according to retrospective studies of patients with schizophrenia and schizophreniform disorder, are shown in Box 6.1.