Final answer:
Transcranial magnetic stimulation (TMS) is a non-invasive treatment for depression using magnetic fields to induce electric currents in the brain, while deep brain stimulation (DBS) is an invasive surgical procedure with electrodes implanted in the brain, both used when CBT and medications are ineffective.
Step-by-step explanation:
Transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS) are alternative treatments for depression, prominently used when traditional therapies such as cognitive behavioral therapy (CBT) and antidepressant medications do not yield sufficient benefit. In TMS, a non-invasive method, a localized and rapidly varying magnetic field is placed close to the brain to induce weak electric currents in targeted areas, potentially leading to the restoration of normal electrical activity in brain tissue. In contrast, DBS is an invasive surgical technique wherein small electrodes are implanted in specific brain regions, and it has been associated with improvement in memory functions, although personality changes have also been reported.
Both treatments are considered when conventional depression therapies fail, and they act through different mechanisms to modulate neurotransmitter release and influence brain function and mood. Psychotherapy, electroconvulsive therapy, and antidepressant medications such as monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed before considering TMS or DBS.