5 Organisation and delivery of psychiatric services5.3 Provision of specific treatments
5.3.2 DBS, rTMS and psychosurgery
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Written by Resident Doctor Committee · Published
Three levels of invasiveness
Technique | Invasiveness | Reversibility | Mechanism |
|---|---|---|---|
Repetitive transcranial magnetic stimulation (rTMS) | Scalp coil, no surgery | Stimulation stops at once | Magnetic pulses induce cortical currents |
Deep brain stimulation (DBS) | Implanted electrodes and chest-wall pulse generator | Can be switched off, but surgery has lasting risks | Modulates a targeted circuit without a lesion |
Psychosurgery | Targeted brain lesion | Irreversible | Destroys a small volume of tissue in a chosen circuit |
rTMS
Sham-controlled randomised trials support rTMS in depression, most strongly in unipolar depression that has not responded to antidepressants.
Depression protocols aim high-frequency stimulation at the left dorsolateral prefrontal cortex.
Patients are treated awake as outpatients, without anaesthesia or admission, on weekdays for 4 to 6 weeks.
National Institute for Health and Care Excellence (NICE) interventional procedures guidance IPG542 finds no major safety concerns and adequate short-term efficacy with variable response.
Under IPG542, rTMS for depression may be used under normal governance and audit arrangements.
For obsessive-compulsive disorder (OCD), rTMS needs special arrangements or research, and other conditions have no NICE support.
Adverse effects and contraindications
Headache from stimulation of scalp muscles and nerves under the coil is the most common side effect, and it is mild and self-limiting.
Implanted metal or electronic hardware in or near the head contraindicates rTMS, because the coil's magnetic field can heat, move or disrupt it, as with a ferromagnetic implant.
DBS
DBS is an invasive neurosurgical treatment: surgeons implant electrodes and hardware in the brain, and stimulation can then be adjusted without further surgery.
Treatment-refractory OCD is the only psychiatric indication with an established evidence base: sham-controlled crossover trials, consistent responder rates and regulatory approval.
In other psychiatric disorders DBS is experimental, mixed in its results or unstudied.
In depression, the sham-controlled BROADEN trial stopped early for futility.
For OCD, DBS targets the anterior limb of the internal capsule.
Surgical risks include intracranial haemorrhage and infection, and hardware infection reaches around 5% in some series.
Stimulation can cause hypomania, disinhibition, impulsivity, hypersexuality, apathy or low mood.
Psychosurgery
Year | Event |
|---|---|
1935 | Egas Moniz conceived the first prefrontal leucotomy and Almeida Lima performed it |
1936 | Freeman adapted it with Watts |
1946 | Freeman devised the transorbital route |
Early operations were imprecise and harmful, and use fell sharply with psychotropic treatment.
Neurosurgery for mental disorder is now reserved for a very narrow set of chronic, treatment-refractory conditions, with intractable OCD the accepted last-line indication in current UK practice.
Modern operations make stereotactic lesions in limbic circuits, and only uncontrolled case series support them.
Procedure | Target |
|---|---|
Anterior cingulotomy | Anterior cingulate cortex and cingulate bundle |
Anterior capsulotomy | Anterior limb of the internal capsule |
Subcaudate tractotomy | Substantia innominata beneath the caudate nucleus |
Limbic leucotomy | Subcaudate tractotomy plus anterior cingulotomy |
Law on psychosurgery
In England and Wales, section 57 of the Mental Health Act 1983 covers operations that destroy brain tissue, in detained and informal patients alike.
It needs the patient's valid consent and independent certification, with no route for a patient who lacks capacity and no emergency override.