Collaborative psychiatric management is founded on a person-centred, holistic assessment leading to a diagnostic formulation that guides decision making. Formulation around the individual person, including their unique history and worldview, can be described with presenting, precipitating, predisposing, perpetuating and protective factors as well as the life context for the individual patient. Allied with this, diagnosis – in which the patient’s unique presentation can be evaluated as sharing characteristics and patterns with other patients – can allow for the individual plan to be guided by a wider frame of reference and knowledge. Such diagnostic frameworks have been developed over millennia and across cultures. As well as being important for individual patient care, they are essential for research and service planning. The development of these diagnostic frameworks is discussed with particular reference to the main international classifications of ICD-11 and DSM-5. It is common for people to have more than one diagnosis, and diagnostic hierarchies are considered. Criticisms of the construct of psychiatric diagnosis are reviewed, and an approach to conducting and describing collaborative psychiatric assessment is described.

This chapter emphasises the importance of the physical health history to holistic psychiatric case assessment. It describes the general approach to this and sets this particularly in the context of patients with serious or severe mental illness. Such patients have substantially increased morbidity and mortality from physical causes compared to the general population, and this increased mortality has been clearly documented for nearly two hundred years. A practical, collaborative and optimistic multilevel approach to attempting to make a difference to these outcomes is described, concluding with fourteen broad, practical areas for achievable interventions.

Psychiatry, according to Johann Christian Reil (1759–1813), the German anatomist who first coined the term, consists of the meeting of two minds, the mind of the patient with the mind of the doctor. As the patient’s story unfolds, the doctor’s task is to recognise the pattern and to do so with compassion. Pattern recognition lies at the heart of the diagnostic process throughout medicine and none more so than in psychiatry, which lacks almost all the special investigations that help clarify diagnosis in other medical specialities. Thus, detailed knowledge of the key features of all the psychiatric disorders, both common and rare, is the core body of information that the psychiatrist will need to acquire during their training years. Because of this, we have provided detailed descriptions of each and every disorder as well as their diagnostic criteria according to DSM-5 and ICD-11.

Mental health services are intended to provide the means to deliver interventions and care to people experiencing mental health problems. This can only be achieved if the staff and resources to provide interventions and care are available. Unfortunately, the current design and resourcing of services can seriously interfere with this happening. Services have evolved over centuries, and many practices are determined by convention and limited by resources, particularly availability of staff in sufficient numbers and with appropriate skills. Mental Health Service provision, commissioning and funding in the NHS, and the evidence base are rapidly developing. Community mental health services, early intervention, assertive outreach, inpatient, outpatient, intensive care units and home treatment teams form key components, but clinical and patient-rated outcomes are still too infrequently measured to guide service development. The complexity of these services and their interfaces with primary care and specialist mental health teams are discussed in this chapter.