Sponsorship bias has been described in drug therapy studies but has not been widely explored in relation to non-pharmacological treatments, such as psychotherapy.
A paper published in The British Journal of Psychiatry
(online, 3 November 2016) looked at 45 studies comparing the efficacy of psychotherapy with pharmacotherapy in depression to see if an industry bias could be detected.
The meta-analysis found that pharmacotherapy was significantly more effective than psychotherapy in the 20 industry-funded studies, while non-industry funded studies showed no difference between the two treatments. The researchers also discovered five instances where one or more authors had not declared a financial conflict of interest.
The team says the level of industry bias detected in the study was subtle but suggests that journals should require authors to declare all industry ties, a policy that has already been adopted by some publications.