Psychosis

Introduction

Psychotic illness is a frequent cause of presentation to the emergency department (ED). It is estimated that in excess of 64,000 people in Australia aged 18 to 64 years have had a psychotic illness and have been in contact with public specialized mental health services each year. This equates to 5 cases per 1000 population or 0.5% of the population. Because these patients are usually severely mentally unwell, they also account for a significant share of the workload of EDs.

The tasks of the ED staff in relation to patients with psychotic illness are complex and varied. Initially, there is usually a need for containment and stabilization of an aroused and frightened patient with impaired reality testing. The patient is often in the hospital unwillingly and frequently following a major crisis in the community or at home. Patient preference should be elicited and considered in treatment and disposition planning wherever possible. There is often a need to manage behavioural disturbance, potentially involving risk of harm to the patient, staff or others, while the patient remains in the ED for significant periods of assessment and for the implementation of disposition plans. It is also important to exclude medical causes for the psychotic symptoms and to consider the presence of co-morbid medical conditions. In determining disposition, consideration must be given to the need for voluntary or involuntary admission or, alternatively, referral to an array of community-based treatment services. Finally, it is important to involve families and other carers in both the assessment phase and in treatment planning. These tasks are summarized in Box 20.5.1 .

Classification

Traditionally, psychotic illnesses were classified into ‘functional’ (i.e. non-organic) psychoses and ‘organic’ psychoses. Developments in psychiatric nosology have expanded this classification and the ICD-10 Classification of Mental and Behavioural Disorders now contains at least 16 different diagnoses, many with several subtypes, which could be used to describe patients with psychotic symptoms.

However, in emergency practice, the differentiation of the specific psychiatric syndrome is not always possible. The pragmatic classification shown in Box 20.5.2 is based on:

• excluding medical causes for the psychotic presentation

• considering the role of alcohol and other drugs of abuse

• making a provisional psychiatric diagnosis as a guide to initial management and

• considering the possibility that the symptoms may be related primarily to psychological stress.

A description of each of these categories is given in the section on clinical features.

Epidemiology and prognosis

The two principal ‘non-organic’ conditions, which involve psychotic presentations are schizophrenia and bipolar disorder (type 1).

The prevalence of schizophrenia is about 1% of the adult population. It is not a rare disorder. The male:female ratio is approximately 1:1. Onset can be at any age, but mostly before the age of 30. Age of onset is slightly later on average for women than for men.

Schizophrenia is usually a chronic condition, but with a variable course. In the long term, about 20% of cases have a good recovery, 20% have recurrent episodes with good recovery between episodes, 40% have recurrent episodes with incomplete remission and 20% have a severe chronic course. The 20-year suicide rate may be as high as 14% to 22%.

The prevalence of bipolar I disorder (which, by definition, means that the patient has had at least one manic episode) is about 1.0% of the population. The male:female ratio is 1:1. The onset is often in late adolescence and 95% of cases have onset before the age of 26.

A patient who has had one episode of mania has about an 80% chance of a recurrence within 5 years. Although there is usually a good recovery between episodes, there is a very high rate of recurrence, with an average of one episode of mania or depression every 2 years, although the frequency of episodes in the individual case varies greatly. The 22-year suicide rate is 13%.

Aetiology and prevention

The aetiology of schizophrenia and bipolar disorder is not well understood, despite intensive research. Both disorders involve genetic and environmental factors. A person who has one parent with schizophrenia has about a 10% chance of developing the disorder; this is similar for bipolar disorder. There is insufficient knowledge about the aetiology of either disorder to suggest effective strategies for primary prevention.

There is considerable scope for secondary prevention, which is early diagnosis and prompt treatment, especially in relation to recurrent episodes. Strategies include the education of patients and families, the identification of early warning signs of relapse and the use of maintenance and prophylactic medication. ED staff can make a major contribution to this preventative work by emphasizing the importance of continuing treatment and facilitating engagement with generalist and specialist mental health services.

Clinical features