Clinical neuromodulation began in psychiatry with electroconvulsive therapy (ECT), but in recent years several new techniques have been developed: repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), vagal nerve stimulation (VNS), trigeminal nerve stimulation (TNS) and deep brain stimulation (DBS). Each works in a different way, although the principle remains to effect therapeutic change through physically modifying brain activity. Their use in different clinical groups varies between techniques, as does their underlying evidence base. Most support currently exists for rTMS, with a more modest, but growing database for tDCS. Understandably, but problematically, most research in the other techniques has, to date, been in unmasked open trials. This article describes the mechanism of action and current evidence base for each technique, and notes the challenges facing future work in this potentially important field and new clinical avenue.