“The new psychological understanding of psychosis”
by Professor Dr. Richard Bentall,
Institute of Psychology, Health & Society, University of Liverpool, United Kingdom
Psychotic disorders are characterised by hallucinations, delusions and related phenomena, with patients typically receiving diagnoses of schizophrenia, schizoaffective disorder or bipolar disorder. Throughout most of the history of psychiatry, these disorders have been seen as genetically-determined brain diseases. However, this approach has not produced breakthroughs in treatment or benefits to patients. Findings in the last twenty years have challenged many of the assumptions of the standard psychiatric model and have led to a new psychological conception of severe mental illness.
It is now recognised that psychotic experiences occur much more commonly in the community than previously thought, supporting the idea of a continuum between psychosis and normal functioning. It has also become recognised that diagnoses such as schizophrenia and bipolar disorder are unlikely to be discrete, separable conditions. The inherited risk of psychotic disorders is less than previously supposed, does not recognise diagnostic boundaries (psychiatric disorders do not ‘breed true’ in families) and, at the molecular level, is massively polygenic (many genes, each with a small effect). By contrast, recent evidence points to the role of many social risk factors including economic disadvantage in childhood, childhood trauma, exposure to urban environments, migration and victimization in adulthood. Some of these effects are, to a degree, symptom-specific. For example, childhood sexual abuse seems to be particularly toxic for hallucinations.
These findings point to a new conception of psychosis, in which particular types of adverse events affect particular cognitive and affective processes, leading to specific symptoms. Symptoms co-occur, leading to syndromes, not because they are the result of common biological causes, but because each symptom of psychosis can play a causal role in provoking other symptoms. By targeting the underlying psychological processes, new approaches to treatment become possible.
Richard Bentall is Professor of Clinical Psychology at Liverpool University and has previously held chairs at Manchester University and Bangor University. He graduated with a BSc and then a PhD in experimental psychology at the University College of North Wales (now Bangor University) and then completed his clinical training at Liverpool University. He also holds an MA in philosophy applied to health care awarded by University College Swansea (now Swansea University). His research interests have mainly focused on psychosis. He has studied the cognitive and emotional mechanisms involved in psychotic symptoms such as hallucinations, paranoid delusions and manic states, using methods ranging from psychological experiments, and experience sampling to functional magnetic resonance imaging. Most recently, his research has focused on why social risk factors (for example childhood adversities such as poverty, abuse, and bullying) provoke the cognitive and emotional changes that lead to these symptoms. In collaboration with colleagues at Manchester and elsewhere he has also conducted large scale randomized controlled trials of psychological interventions for people diagnosed with schizophrenia, bipolar disorder and prodromal psychosis. He has published over 200 peer-review papers and a number of books including Madness explained: Psychosis and human nature (Penguin, 2003) and Doctoring the mind: Why psychiatric treatments fail (Penguin, 2009).