This chapter outlines the historical development of psychiatric intensive care as a specialty. It presents an overview of the current facilities and patients based on the most recent UK National Surveys and current admission criteria taken from national guidelines. Further, it discusses how psychiatric intensive care interfaces with general adult services, mental health secure estates, the criminal justice system and community mental health services. Finally, the chapter presents an outline of the future strategy for the development of the specialty.

This chapter focuses on the management of acutely disturbed patients in psychiatric intensive care units (PICUs). It provides an overview of the nature of acutely disturbed patients, their symptoms and behaviours and the general challenges faced in managing their disturbance. The chapter discusses a philosophy for dealing with disturbed patients, appropriate assessment and care planning and a range of interventions that can be utilised, including verbal de-escalation, medication, physical intervention, seclusion and segregation. It also explores the development of activity and engagement programs for acute disturbance and the training and experience mix required for effective management. The roles of multidisciplinary team (MDT) members in the management of acute disturbance are outlined as well. The chapter highlights the prevalence of violence and aggression in healthcare settings and the importance of creating an informed and supported environment for staff to minimise risks. It concludes with recommendations for ensuring a safe environment and a philosophy of person-centred care in the management of acutely disturbed patients.

This chapter outlines the scale of the problem of substance misuse in the context of psychiatric intensive care units (PICUs) and related services. Further, it discusses relevant health inequalities and how these impact on the issue. It also reviews the characteristics of dually diagnosed patients and illustrates how substance use commonly presents in clinical practice in PICUs, low secure units (LSUs) and locked rehabilitation units (LRUs).

The species–area relationship (SAR) has been described as one of the few general patterns in ecology. Although there are many types of SAR, here we are concerned solely with the so-called species accumulation curve (SAC). The theoretical basis of this relationship is not well established. Here, we suggest that extreme value theory, also known as the statistics of extremes, provides a theoretical foundation for, as well as functions to fit, empirical species accumulation curves. Among the several procedures in extreme value theory, the appropriate way to deal with the species accumulation curve is the so-called block minima procedure. We first provide a brief description of this approach and the relevant formulas. We then illustrate the application of the block minima approach using data on tree species from a 50 ha plot in Barro Colorado Island, Panama. We conclude by discussing the extent to which the assumptions under which the extreme types theorem occurs are confirmed by the data. Although we recognize limitations to the present application of extreme value theory, we predict that it will provide fertile ground for future work on the theory of SARs and its application in the fields of ecology, biogeography and conservation.