Three Paths Into the Brain
Three modalities dominate non-invasive brain stimulation: TMS, tDCS, and Focused Ultrasound. Each uses a different physical mechanism with different tradeoffs.
TMS — Magnetic Pulses
FDA-cleared for depression (2008), OCD (2018), smoking cessation (2020). The SAINT protocol achieved 79% remission in treatment-resistant depression. Requires clinic visits.
tDCS — Weak Electrical Current
Flow FL-100 is FDA-cleared for depression. Home-use devices exist ($300-500). Evidence weaker than TMS but far more accessible.
Focused Ultrasound
LIFU uses acoustic energy at precise deep-brain targets. The only modality reaching the thalamus and basal ganglia non-invasively. Promising OCD results from UVA. No consumer devices yet.
The Bottom Line
TMS is the gold standard. tDCS is the accessibility play. Focused ultrasound is the future — 3-5 years from consumer availability.