[Brain stimulation: the most direct form of neurostimulation]

Brain stimulation is the most direct form of neuromodulation. Direct brain stimulation is an older procedure that has taken various forms, but 'non-invasive brain stimulation' is a more recent development.

To provide an overview of the current arsenal of non-invasive brain stimulation techniques.

We discuss the underlying principles, the pros and cons, and the applicability of non-invasive brain stimulation in experimental research and treatment of neuropsychiatric disorders.

Non-invasive brain stimulation is a direct form of neuromodulation, which is not invasive, harmful or painful. Its effects are in principle temporary, which makes the technique suitable for experimental research. At the same time, temporary effects can have lasting clinical consequences, if they target neuroplasticity to aid rehabilitation or alleviate symptoms.

Whereas the value of non-invasive brain stimulation for research purposes is undisputed, its efficacy and value as a treatment for neuropsychiatric disorders are still being debated. Nevertheless, the accumulated evidence about the clinical efficacy of the treatment for certain disorders is sufficiently compelling to start thinking about European regulations and standard medical insurance coverage.