Curtailing worry reduces key schizophrenia symptom

4 March 2015

Just six sessions of cognitive behavioural therapy (CBT) can substantially reduce psychiatric patients’ levels of worrying, which in turn reduces the severity of delusions of persecution, a new clinical trial has found.

Using CBT in this way could potentially help to prevent mental illnesses before they happen in at-risk people. 

The study, published in the journal Lancet Psychiatry, was funded by the UK’s Efficacy and Mechanism Evaluation (EME) Programme, an MRC and NIHR partnership. It was carried out by researchers at the Universities of Oxford, Southampton, and Manchester.

Persecutory delusions are unrealistic beliefs that others are intentionally trying to harm the person. This severe paranoia is a key problem in many mental health conditions, such as schizophrenia.

The 150 NHS patients in the trial had been diagnosed with schizophrenia or a related mental health problem. They all had severe paranoia, which had persisted despite medication.

Six sessions of cognitive behavioural therapy (CBT) focused upon reducing worry reduced the severity of persecutory delusions, the researchers found.

The patients were much happier and less fearful of other people after therapy. These effects lasted at least six months.

A study participant commented, ‘The breakthrough was that I was able to, with the help of my psychologist, come up with a strategy – that is, when worry is gripping me I would say ‘Excuse me worry, I need to interrupt you because…’. I sometime worry about people trying to harm me but now I can interrupt my worry and do something else’.

Professor Daniel Freeman at the University of Oxford, the study leader, said: ‘We know that worry brings implausible ideas to mind, keeps them there, and stirs up fears. It is one factor that causes paranoia. We’ve translated this knowledge into a new treatment. The clinical trial convincingly shows that teaching people how to limit worry has a major impact on long-standing fears about other people. Brief, targeted, and active psychological help makes a real difference for patients with paranoia.’

‘Paranoid thinking is remarkably common in the general population, which is not surprising since every day we have to make decisions to trust or mistrust. The fears range from thinking that others are spreading malicious rumours to concerns about imminent physical attack. When paranoia gets a strong grip on a person it is typically associated with anxiety, depression, and isolation. We need much more of a focus upon problems such as paranoia. This study offers real hope and a major step forward.

‘ The researchers are now combining the worry reduction intervention with the targeting of factors such as sleep deprivation and low self-esteem. They aim to come up with an intervention that helps many patients recover from persistent persecutory delusions.

Professor David Kingdon at the University of Southampton, a researcher in the trial team, said: ‘This intervention is very timely in view of the introduction of access and waiting standards for early psychosis and development of psychosis pathways. The hope is that there is not a large gap in time between the research showing it works and people actually getting it in services.’

The trial statistician, Professor Graham Dunn of Manchester University said ‘This was a well-specified trial with an intervention specifically targeted to reduce worry which, in turn, would lead to a corresponding reduction in the severity of paranoia. The effects of the intervention on both levels of worry and paranoia have been clearly demonstrated and our statistical analysis indicates that much of the change in paranoia can be explained by the indirect effects of the intervention through worry.’

For more information contact: Professor Daniel Freeman, [email protected]

Alternatively contact the Oxford University News Office on +44 (0)1865 270046 or email [email protected]

For copies of the full paper, please contact The Lancet Psychiatry press office: [email protected], +44 (0)207 424 4249

Notes to Editors:

  • A report of the research, entitled ‘Effects of cognitive behaviour therapy for worry on persecutory delusions in patients with psychosis (WIT): a parallel, single-blind, randomised controlled trial with a mediation analysis’, is published in The Lancet Psychiatry.
  • The project is managed by the Efficacy and Mechanism Evaluation Programme, an MRC and NIHR partnership, that supports later-phase ‘science-driven’ clinical trials and evaluative studies, which seek to determine whether a health intervention  (e.g. a drug, diagnostic technique or device) works and in some cases how or why it works. The programme is funded by the MRC and NIHR, with contributions from the CSO in Scotland, NISCHR in Wales and the HSC R&D Division, Public Health Agency in Northern Ireland (
  • The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government’s strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website (
  • The Medical Research Council has been at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers’ money in some of the best medical research in the world across every area of health. Twenty-nine MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms ( This article presents independent research supported by an MRC and NIHR partnership. The views expressed are those of the author(s) and not necessarily those of the NHS, the MRC, the NIHR or the Department of Health.
  • The University of Manchester, a member of the prestigious Russell Group of British universities, is the largest and most popular university in the UK. It has 20 academic schools and hundreds of specialist research groups undertaking pioneering multi-disciplinary teaching and research of worldwide significance. The University of Manchester is one of the country’s major research institutions, rated fifth in the UK in terms of ‘research power’ (REF 2014), and has had no fewer than 25 Nobel laureates either work or study there. The University had an annual income of £886 million in 2013/14.