Scaling up a success story: how do we achieve universal access to transcranial magnetic stimulation?

Purpose of review: Over one billion people suffer from psychiatric and/or neurological disorders for which transcranial magnetic stimulation (TMS) has shown efficacy. Achieving widespread TMS access will require major improvements to cost and convenience. A key figure of merit for a given TMS protocol concerns not its remission rate or tolerability, but simply its treatment time per remission (TTPR).

Recent findings: Outcomes for conventional bilateral TMS protocols imply a TTPR of more than 100 h - incompatible with widespread access. However, briefer accelerated and/or theta-burst protocols may improve TTPR to less than 20 h. Personalization strategies that improve remission rates sometime improve TTPR, depending on associated cost-penalties of time or complexity. A potentially groundbreaking new strategy to improve TTPR involves pharmacological augmentation of neuroplasticity, using agents such as D-cycloserine. Plasticity-augmentation may improve TTPR by improving remission rates, and by reducing the number of required sessions. Recent literature suggests that TTPR values of under 5 h per remission may be achievable via neuroplasticity augmentation.

Summary: The most recent plasticity-augmented TMS protocols may approach or exceed cost-parity with pharmacotherapy, in terms of reducing the prevalence of depression. With the health economics of TMS improving steadily, a pathway to universal access may be within reach.