Classification of drug treatments for depression is described noting the ambiguities of current terminology and the move towards standardised nomenclature based on pharmacology and mode of action, such as that proposed by the Neuroscience-based Nomenclature group. Antidepressant drugs are described in terms of background, mechanism of action, pharmacokinetics, side effects, interactions, contraindications and toxicity in overdose. Groups include selective serotonin re-uptake inhibitors (SSRI), serotonin and noradrenaline re-uptake inhibitors (SNRI), tricyclics, noradrenergic and specific serotoninergic antidepressants (NaSSA), monoamine oxidase inhibitors (MAOI) and others such as buproprion, agomelatine, reboxetine, trazadone and vortioxetine. Augmentary medications are also described, including antipsychotics, antiepileptics and lithium. Developments with the use of ketamine and other compounds are discussed.

The classification of physical treatments for depression is into neuromodulatory (e.g. electroconvulsive therapy, transcranial magnetic stimulation, deep brain stimulation and phototherapy) and neuroablative techniques (e.g. stereotactic psychosurgery).

There has been a resurgence in the practice of psychosurgery in the last decade primarily for depression and obsessive compulsive disorder. This is due to the application of deep brain stimulation (which has largely replaced lesioning) and to a greater understanding of the imaging correlates of mental illness. Psychosurgery is expanding well beyond these indications. Many ethical challenges arise, including informed consent, establishing the efficacy of these procedures from the literature and in the design of new studies, the harm versus benefit ratio, and the role of institutional and governmental regulatory control over psychosurgery. Psychosurgery remains experimental or at least investigational and the ethical considerations should be of prime importance for any practitioner undertaking this surgery. We propose eighteen principles as a basis for a regulatory framework of psychosurgery. Neurosurgeons who perform psychosurgery have an immense responsibility to guard against a repeat of the failures of the past.