Cognitive behavioural therapy (CBT) may not be an effective treatment for the symptoms of schizophrenia, a new study suggests.

Schizophrenia is a serious mental health condition characterised by disturbances in a person's thoughts, perceptions, emotions and behaviour. Symptoms can include delusions, hallucinations, behaviour change, social withdrawal and problems sleeping.

The condition affects around one in every 100 people - an estimated 41,000 people in Ireland are currently affected. There are a number of treatments that may be used to treat schizophrenia, including drugs and various types of therapy, including CBT.

CBT is often referred to as a ‘talking therapy'. It aims to help people to better understand how their thoughts and feelings influence their behaviours. It is used to treat a range of mental health problems, including depression, obsessive compulsive disorder (OCD) and psychosis.

Currently, the UK's National Institute for Health and Care Excellence (NICE) contends that CBT is an effective treatment for schizophrenia and should be recommended to all people with the condition.

UK researchers decided to investigate this further. They carried out the most extensive study ever undertaken into the effects of CBT on the symptoms of schizophrenia.

"This study is a new meta-analysis of CBT in the treatment of schizophrenia. It is the most comprehensive study of its effect on symptoms ever undertaken - covering 50 randomised controlled trials published over the last 20 years. We even translated papers from foreign languages, such as Chinese, so our study covers everything worthy of examination," explained Prof Keith Laws of the University of Hertfordshire.

The study found that CBT had only a small therapeautic effect on the symptoms of schizophrenia. When it came specifically to hallucinations and delusions, the effect remained small, even though this was what CBT was originally developed to target.

Furthermore, in certain types of studies, these small effects disappeared altogether.

The researchers said that these findings raise the question of whether CBT should be routinely recommended to everyone with schizophrenia.

Details of these findings are published in the British Journal of Psychiatry.