Antidepressants work by modifying the actions of neurotransmitters (brain chemicals) or modifying neurotransmitter receptors. TMS induces small electrical currents in the brain which improve the connections between brain cells and increase the growth of brain cells. Treatment with antidepressants involves taking medications which are absorbed through the mouth, stomach and small intestine with possible side effects throughout the body. They can cause adverse effects such as gastrointestinal side effects weight gain and can have an effect on sexual function (reduced sex drive and delayed ejaculation). Patients can also be allergic to antidepressants or other chemicals contained in the medication.
TMS does not involve the ingestion of chemicals, therefore, there are no systemic adverse effects. There is no impact on the digestive system, on sexual function, cognition and there are no allergic responses. The only side effect with TMS that is greater than 5% is transient site pain, headache which abates typically within the first week as patients desensitize to the treatment.
Antidepressants modify brain chemicals and receptors via an effect on protein synthesis, they can take between three to six weeks to work, while TMS has a faster onset of action. Studies show that in patients who have not responded to two or three antidepressants the response rate the next antidepressant is 10-15%. If such patients are given TMS, the response rate is about 60%.