Even when such data were available, Gelenberg and colleagues often found fault with them.
For example, they noted that transcranial magnetic stimulation had been compared in several trials with electroconvulsive therapy, a mainstay of treatment for severe depression for decades, but some of the results set off alarm bells.
"TMS has been found in randomized studies to be either less effective than ECT or comparable in efficacy to ECT," Gelenberg and colleagues wrote, "but in the latter studies TMS was more effective and ECT was less effective than is typically seen in clinical trials" -- apparently a hint that physicians should take those results with a grain of salt.
Among nonpharmacologic therapies, ECT still has by far the largest evidence base for its efficacy, the guideline authors indicated.
As in the last version of the guideline, the update is careful to stress the importance of psychotherapy in conjunction with drug and device-based treatments, as well as the many individual patient factors that may affect treatment choices.
Bernstein indicated in her statement that the APA is still grappling with how to manage conflicts of interest. "Early this year, the Council of Medical Specialty Societies issued principles for preventing undue influence of industry in the activities of its member societies," she said.
"One of the principles states that chairs of work groups and the majority of work group members that develop practice guidelines should have no conflicts of interest. How 'conflict of interest' is defined and monitored remains an issue in all of medicine," Bernstein added.
She said the APA would probably adopt "congruent policies" including specific rules for guideline authors.