A study in The Lancet found the therapy was a safe and effective alternative to medication, with patients seeing improved psychiatric symptoms and no increased risk of adverse effects compared with usual care.
Researchers said it should routinely be offered to all patients unable or unwilling to take drug treatments.
Around half of patients with schizophrenia do not take first-line antipsychotic treatment as many fear side-effects ranging from increased weight gain to an increased risk of sudden cardiac death.
Recent studies have cast doubt on the benefits of these drugs and claimed adverse effects have been underestimated.
CBT has proved to be effective in combination with antipsychotic drugs, yet little research has been conducted into stand-alone use.
In the study, researchers recruited 74 patients aged 16-65 with schizophrenia spectrum disorders, all of whom had chosen not to take antipsychotic drugs for at least six months.
Researchers led by a University of Manchester team randomly allocated patients to receive either CBT alongside usual care, or usual care alone, and then tracked psychiatric outcomes using a battery of tests over the next 18 months.
They found that average Positive and Negative Syndrome Scale (PANSS) scores improved by more in the CBT group than those receiving usual care.
At 18 months, the study continued to track 34 participants. Seven (41%) of the 17 patients receiving CBT had an improvement of more than 50% in the PANSS total score compared with three (18%) of 17 receiving treatment as usual.
Meanwhile, rates of serious adverse events were similar between the groups, with two in the CBT group and six among those receiving standard treatment.
'Safe and acceptable'
Researchers said CBT should be seen as a safe and acceptable alternative to medication for a patient group who are considered to be very challenging to engage with by mental health services.
Lead author Professor Anthony Morrison from the University of Manchester said: ‘Antipsychotic medication, while beneficial for many people, can have severe side effects. Evidence-based alternatives should be available to those who choose not to take these drugs.’
However, fellow lead author Professor Douglas Turkington from Newcastle University warned that patients on antipsychotics should not stop taking their medicine because of the major risk of relapse.