An advanced version of a procedure that uses magnetic fields to stimulate brain nerve cells appears to be extremely effective for combat-related post-traumatic stress disorder, according to a study of active military and veterans.

That procedure in combination with psychotherapy successfully treated 85% of participants with PTSD who received it in the trial, they reported.

Overall, 119 soldiers and former soldiers with severe combat-related PTSD were randomly assigned to receive psychotherapy with or without an MRI-guided, robot-controlled form of transcranial magnetic stimulation, called “navigated TMS,” during a 30-day residential program at Laurel Ridge Treatment Center in San Antonio. Navigated TMS guides placement of the magnetic device to the exact spot that should be targeted based on the patient’s unique anatomy and brain structure, according to a report of the study published in JAMA Network Open.

After one month, 85% of those who received the navigated TMS treatment had clinically significant symptom reductions, enough to greatly improve their quality of life. That compared with 59% of those who received a “sham” TMS procedure as a control, the researchers reported.

Soldiers and veterans receiving the TMS add-on were more likely to maintain their treatment gains over time, the researchers also found.

“These are exciting findings for the hundreds of thousands of U.S. service members and veterans suffering from combat-related PTSD,” study leader Dr. Peter Fox of UT Health San Antonio said in a statement.