Read: CBT: How therapy works
Reporting in The Lancet, British researchers say that the treatment can help ease patients' psychotic symptoms and boost their personal and social functioning.
They note that many people with schizophrenia cannot take standard medications.
"As many as half of all people with schizophrenia choose not to take drugs because of side effects that can include serious weight gain, development of metabolic disorders and an increased risk of sudden cardiac death, because the treatment is not felt to be effective, or because they do not perceive that they need treatment," study author Anthony Morrison, from the University of Manchester, said in a journal news release.
Changing detrimental thought patterns
"Currently, no evidence-based safe and effective treatment alternative exists," he added.
To see if cognitive behavioural therapy might work in these cases, Morrison's team tracked the outcomes of 74 schizophrenia patients aged 16-65 who had stopped taking antipsychotic drugs for at least six months.
As part of the treatment, a therapist worked with some of the patients to help them change detrimental thought patterns and behaviours.
The patients in the cognitive behavioural therapy group showed greater improvements after 18 months than those who didn't receive the therapy, the study found.
Prior research has shown that schizophrenia patients benefit from cognitive therapy in combination with antipsychotic drugs, but the effectiveness of cognitive therapy in patients who were not taking medication hadn't been known.
The findings show "that cognitive therapy is an acceptable intervention for a population who are usually considered to be very challenging to engage in mental health services," Morrison said.
Two experts in the United States said these early results are promising, but more study may be needed.
"Non-compliance or medication refusal is a substantial therapeutic issue" when treating patients with schizophrenia, said Dr Russell Joffe, chairman of psychiatry and behavioural science at Staten Island University Hospital, in New York City.
He noted that's there's been good data to support the use of cognitive behavioural therapy in mood or anxiety disorders, "but there is limited data in psychotic disorders" such as schizophrenia. Still, the study was small and focused on short-term treatment, whereas "schizophrenia is a chronic and persistent mental illness," Joffe said.
"Demonstrating the effectiveness of new treatments for major psychiatric illness is always a good thing, given the enormous burden of suffering," he said. "This data, however, is very preliminary and further research needs to be done before confronting the substantial logistic challenges in implementing such treatment on a broad clinical basis."
Mainstay of treatment
Dr Mary Badaracco is a professor at the NYU School of Medicine and the director of psychiatry at Bellevue Hospital Centre in New York City. She said the study "adds to the growing body of evidence supporting the usefulness of cognitive behavioural therapy approaches in patients with schizophrenia, an illness that can cause lifelong suffering and heartbreaking disability."
She stressed, however, that "the results of this study should not be used to encourage patients not to take medications, which remain the mainstay of treatment."
Morrison's team agreed with Badaracco that schizophrenia patients on antipsychotics should not suddenly stop taking the drugs. They should first discuss the matter with their doctor.
"The study does, however, underline the usefulness of cognitive behavioural therapy – an intervention that is free of the sometimes intolerable effects of some medications," Badaracco said. The new finding may also provide "another source of hope for the 1% of the world's population that suffers from this illness."