|
Professor Anthony Harris Psychiatrist , University of Sydney School of Medicine , Faculty of Medicine and Health ; Westmead Institute for Medical Research , Sydney , NSW .
Copyright © 2022 Australian Doctor All rights reserved . No part of this publication may be reproduced , distributed , or transmitted in any form or by any means without the prior written permission of the publisher . For permission requests , email : howtotreat @ adg . com . au .
This information was correct at the time of publication : 1 April 2022
|
BACKGROUND
SCHIZOPHRENIA is the most common of the psychotic illnesses . 1 It usually starts early in adult life ; its chronicity blights the lives of many of the people who have it and the families who care for them . Life expectancy is around 15 years shorter for those with schizophrenia , mostly due to poor physical health ; however , around 5 % of people with schizophrenia complete suicide . 2
The care of people with schizophrenia has been improved by an increase in the range of antipsychotic medications available for pharmacotherapy and the potential expansion of quality psychosocial interventions using the National Disability Insurance Scheme ( NDIS ). Significant challenges remain in individualising pharmacotherapy , maintaining treatment compliance and accessing good quality psychosocial treatments .
The GP plays a central role in the care of someone with schizophrenia by maintaining pharmacotherapy , maximising physical health and steering the patient with schizophrenia , and their carers , through the maze of mental health care .
This How to Treat discusses what we know of the aetiology of the
|
disorder , refreshes readers memories about the symptoms , signs and diagnosis of schizophrenia and aims to provide a practical biopsychosocial approach to treatment .
AETIOLOGY
ALTHOUGH we lack a clear pathophysiology of schizophrenia , the disorder can be understood as the result of a genetic vulnerability interacting with developmental stressors . The genetics of schizophrenia is complex with over 128 different loci , mostly of low effect size , contributing to the risk of developing the disorder . 3 The genes predisposing to schizophrenia also overlap with those associated with a range of other psychiatric disorders , for example , bipolar disorder , possibly contributing to the diagnostic instability seen in psychiatric diagnosis . No single gene or class of gene appear to be necessary for the development of the disorder . 4 Even in monozygotic twins the chance of both developing schizophrenia is no more than about 50 %, pointing to the importance of environmental or gene plus environment interactions in the disorder . 5
The environmental factors that interact with the genetic vulnerability
|
are diverse and include prenatal factors such as maternal viral illness , starvation or bereavement in the first trimester , perinatal factors such as obstetric complications and early life stressors such as bullying , abuse or neglect ( see figures 1 and 2 ). These can be compounded by later life stressors such as isolation , substance abuse or autoimmune illness to result in the development of a psychotic illness such as schizophrenia . 6 , 7 This multiple-hit stress vulnerability model of illness in which the underlying genetic risk is compounded by early life events provides a better understanding of the development of the illness and creates a platform for interventions to help decrease the prevalence of the illness as well as treat it successfully . 8
EPIDEMIOLOGY
SCHIZOPHRENIA has a median incidence of 15.2 ( 7.7-43.0 )/ 100,000 and a lifetime incidence of 7.2 / 1000 people . 9 , 10 This is a little less than 1 % of the Australian population . More men than women are diagnosed with schizophrenia and for most people ( 65 %) the age of onset of their illness is under 25 with their first symptoms being evident in the teenage years ( see figure 3 ). 1
|
The 2010 second Australian national survey of psychosis reported that few people in Australia with schizophrenia work . Disability and labour practices mean that only about 31 % of people with a psychotic disorder had any sort of work over a 12-month period and 85 % were dependent upon government support . Because of this high level of welfare dependency , very few people with schizophrenia own their own home and most are reliant upon public housing or still live with their family of origin , and 13 % were homeless . They are also very isolated ( see figure 4 ) with few ever partnering — only a quarter of women and 12 % of men were living with a partner — leaving them alone or dependent upon their family for friendship and support . 1
SIGNS AND SYMPTOMS
THE signs and symptoms of schizophrenia
are protean in that two individuals diagnosed with the disorder may appear quite dissimilar cross sectionally ( see table 1 ). Although there are several ways in which the signs and symptoms of the disorder can be divided , conceptualising them in these five domains helps with
|