Magnetic therapy is a non-invasive, drug-free therapy which could help thousands of people suffering from depression.
Results from tests on more than severely depressed 300 patients found 58 percent achieved a positive response while more than a third went into remission.
Researchers from the University of California (Los Angeles), US, were testing the Food and Drug Administration-approved NeuroStar TMS Therapy, which works by beaming magnetic pulses through the skull. These trigger small electrical charges that spark brain cells to fire.
Ian Cook from California, who led the study, said: "The NeuroStar TMS not only reduces the symptomatic suffering of patients, but lessens the disability of depression with important implications for these individuals' ability to return to functioning effectively at home, in the workplace, and in the community."
During each half-hour session the patient was placed under a treatment coil as big as a fist. It sent a pulsed magnetic field an inch under the scalp to the prefrontal cortex, the ante cingulate cortex and the limbic system, three brain areas thought to regulate mood, the Daily Mail reports.
The magnetic field is similar in strength to that created by an MRI machine and sparks off very small electrical currents within the brain. This stimulates neuron activity thought to provide relief from depression.
Anti-depressants are released into the blood, which can cause widespread physical side-effects such as hot flushes and nausea. However, supporters of NeuroStar say because it's a targeted therapy it only causes mild scalp pain.
After an average of five weeks of NeuroStar treatment, the percentage of patients reporting extreme problems with anxiety and depression decreased by 42.2 percent.
H. Brent Sovason from the Stanford University, said: "These data reinforce the clinical efficacy of the TMS therapy as a viable option for patients living with major depression who have not achieved or maintained symptom improvement with oral anti-depressants."
These findings were presented at the annual meeting of the American Psychiatric Association.