Electroconvulsive Therapy (ECT)
ECT is the artificial induction of grand mal (tonic-clonic) seizures through the application of electrical currents through the brain. It is the most effective treatment for major depressive disorder (80% success rate, especially with psychotic featuers), as well as mania and catatonia. It is often used for patients who cannot tolerate medication or have failed other treatment. Typically, a course of ECT is administered 2-3 times weekly, with a normal course consisting of 6 – 12 sessions spread over 3 – 6 weeks. Improvement is usually demonstrated after the 2nd or 3rd session.
Historical perspective of using convulsions to treat mental illness
ECT was introduced in 1938 by 2 Italian doctors, Ugo Cerletti and Lucio Bini to replace insulin coma therapy (1933) and pharmaco-convuslive therapy (1934). There was an assumption that epilepsy and schizphrenia never occured together, hence the artificial induction of to treat schizophrenia. Early ECTs were used without anaesthesia or muscle relaxants resulting in fractures.
Types of ECT based on electrode placement
| Types of ECT | Description |
|---|---|
| Bilateral ECT | On electrole on either side of the scalp. Includes bitemporal ECT, bifrontal ECT, left anterior right temporal (LART) ect. Bitemproal ect is the most common type followed by unilateral ECT. Has greater overall effectiveness than unilateral ECT (first-choice) and has a quicker onset of antidepressant effect (particulalry indicated for severely depressed and actively suicidal patients. |
| Unilateral ECT | Both electrodes on the non-dominant side (almost always the right side). Has fewer cognitive side effects (first-line in the elderly or in those with pre-existing cognitive impairment) |
Types of ECT based on the use of muscle relaxants
| Type of ECT | Description |
|---|---|
| Modified ECT | A rapid-onset general anaesthesia followed by a short-acting muscle relaxant (succinylcholine) before ECT is administerd. This reduces the risk of musculo-skeletal injuries e.g. fractures or dislocations |
| Unmodified ECT | No muscle relaxant is given. May be used in setting that lack anaesthetic facilities. |
- Indications for ECT
- Major depressive disorder: severe life-threatening e.g. not eating/drinking or suicidal, refractory to treatment, catatonic, psychotic depression
- Bipolar disorder: catatonic, severe manic episode, treatment-resistant mania
- Acute psychosis
- Schizophrenia/Schizoaffective: catatonic, major mood component, treatment resistant schizophrenia (augmented with clozapine)
- Post-partum psychosis and depression
- Depression in pregnancy
- Catatonic regardless of the underlying cause
- Severe neuroleptic malignant syndrome
- Absolute contraindications to ECT (specific to ECT)
- Raised intracranial pressure (the only absolute contraindication)
- Relative contraindications to ECT (immediate risk of death e.g. due to severe depression may override some of these contraindication)
- Recent stroke or MI
- Unstable arrhythmia
- Coronary artery disease
- Cerebrovascular disease
- Hypertension
- Aneurysms
- Arrhythmia
- Procedure of ECT
- Conset and pre-procedural investigations are obtained e.g. CBC, UECs, EKG and LFTs as indicated
- Premedication with atropine and metroclopramide
- Induction of general anaesthesia using methohexital or propofol
- A muscle relaxant is given before ECT is applied
- ECT is delivered by two electrodes placed on specific points on the scalp, and connected to the ECT machine. The electircal charge has to be equal or greater than the seizure threshold (usually less than 100 millcoulombs).
- A brief pulse of electrical current is passed through the brain resulting in generalized convulsions
- The EEG duration of convulsions is usually 25% higher than the duration of visible peripheral convulsions. Greater importance is given on the quality (generalized convulsion on EEG) rather than the duration (previously considered ≥ 20 seconds) to be therapeutic
- Seizures should be discontinued using a Benzodiazepine if a seizure lasts more than 1 minute
- Mechanism of action of ECT
- Stimulates the vagus nerve (causes bradycardia and can lead to arrhythmia)
- Increases blood brain barrier permeability
- Changes in blood flow/activity in different brain regions e.g. prefrontal cortex
- Changes in synaptic plasticity and neurogenesis
- Changes in the volume and cell density of the hippocampus
- Changes in the expression of genes coding for proteins involved in brain function
- Increases the leves of hormones e.g. growth hormone, prolactin and brain derived neurotrophic factor
- Increases the levels of neurotransmitters e.g. noradrenaline, serotonin
- Changes in the activity of neuropeptide Y
- Induces alpha waves and theta waves associated with relaxation calm and mood regulation
- Side effects of ECT
- Headache
- Confusion
- Memory problems (retrograde and anterograde amnesia): may be short-term (< 1 week) or long-term (rarely lasting over 6 months)
- May precipitate mania in patients with bipolar disorder (like any other antidepressant treatment)
- Complicatins from the use of general anaesthesia and muscle relaxants
- Non-specific side effects e.g. muscle weakness, muscle aches, nausea an danorexia
- Strategies to reduce cognitive-side effects
- Unilateral ECT instead of bilateral ECT
- Increase interval between sessions
- Ensuring that the dose given does not exceed the patient’s seizure threshold
- Brief pulse ECT instead of sine-wave ECT
- Stopping or adjusting the dose of psychotropics with potential cognitive side effects
- Continuation or Maintenance ECT
- ECT given during the first year folllowing an acute course of ECT. After 1 year it is called Maintenance ECT.
- This is given to patients who respond well to ECT but quickly relapse after a regular course of ECT despite maintenance psychotherapy
Repetitive Transcranial Magnetic Stimulation (rTMS)
rTMS is the induciton of an focal seizures using a magnetic field that is generated in a pulsatile and repetitive means. It is non-invasive and does not require sedation. The position of the rTMS coil varies for the condition being treated. For depression, rTMS coil is placed on the scalp over the area corresponding to the left dorsolateral prefrontal cortex (L-DLPFC – usually hypoactive in depression). A typical course involves 5 sessions a week for 6 weeks, followed by a period of tapering over 3 weeks with 2 sessions per week.
rTMS was introduced by Anthony Barkery in 1985 in the UK.
- Indications for rTMS
- Depression (the main indication)
- Other psychiatric conditions: OCD, anxiety, addiction
- Neurological: epilepsy, post-stroke disability, movement disorders, migraine prophylaxis, multiple sclerosis, ALS
- Others: chronic pain, tinnitus, conversion disorder
- Side effects of Rtms
- Headache
- Scalp discomfort
- Facial twitching
- Light-headedness/dizziness
- Rare: seizures, precipitation of mania/hypomania, hearing loss, emergence of psychotic symptoms
- Contraindication to rTMS
- Presence of metal (apart from dental) e.g. cardiac pacemaker, cochlear implant, metal prostheses, implanted pulse generators of DBS or VNS
Vagus Nerve Stimulation (VNS)
Vagus nerve stimulation is done by stimulating the vagus nerve using an implanted pulse generator (IPG) placed subscutaneously in the left upper chest. It is done under general anaesthesia. The left vagus nerve is identified and an electrical lead is wrapped around it and tunnelled subcutaneously to the IPG. The IPG is then activated as during the next outpatient visit.
- Indications for VNS
- Treatment-resitant epilepsy (more common than depression)
- Treatment-resistant depression
- Mechanism of VNS
- Increases seizure threshold due to intermittent stimulation
- Release of inhibitor neurotransmitters e.g. GABA
- Increase in serotonergic and noradrenergic neurotransmission
- Increase int he level of 5HIAA in CSF
- Changes in blood flow to different parts of the brain
- Modulation of GABA and glutamate transmission
- Side effects of VNS
- Vocal cord paralysis, change in voice, hoarsness or cough
- Throat pain or discomfort
- Difficulty swallowing or breathing
- Bradycardia
- Nausea or abdmonial discomfort
- Headache
- Insomnia
- Local effects of surgery
Deep Brain Stimulation (DBS)
Deep brain stumulation is done by stimulating the DBS target in brain tissue using bilateral electrodes connected subcutaneousl to bilateral implanted pulse generators (IPGs) under general or local anaesthesia.
Areas stimulated in DBS
| Category | Areas stimulate |
|---|---|
| Psychiatric | Ventral capsule/ventral striatum, nucleus accumbens, subcallosal cingulate cortex (area 25), ventral anterior limb of the internal capsule, median forebrain bundle |
| Neurological | Subthalamic nucleus, globus pallidus interna, thalamus |
- Indications for deep brain stimulation
- Parkinson’s disease
- Severe dystonia
- Sevre tremors and other movement disorder
- Severe, treatment-resistant depression
- Severe, treatment-resistant OCD
- Others: anorexia nervosa, tourette syndrome, addictions, aggression and PTSD
- Adverse effects of DBS
- Hemorrhage
- Infection
- Displacement of elctrode
- Dysfunction of the DBS system
- Delirium
- Insmnia
- Hypomania or mania
- Weight gain
- Epilepsy
Psychosurgery (Psychiatric Neurosurgery
Psychosurgery was pioneered by Egas Moniz (nobel prize 1949), a portuguese neurologist who performed prefrontal leucotomy. Walter Freeman, an american neurologist, also perofrmed transorbital lobotomy using the ‘Icepick Mehtod’ indiscriminately in the 1950s with high rates of major adverse effects. The use of psychosurgery has declined following the advent of neuroleptics. Modern psychosurgery is safer, more refined, and is done in for extremely ill, chronically disabled, treatment-resistant patients.
- Method
- Uses sterotaxis to pinpoints areas of interest (using coordinates in X, Y and Z surgeries)
- Thermocoagulation: heat is directed to the area of interest to cause the lesions. Lesiosn develop immediately. It is more invasive and needs burr holes
- Radiosurgery: ionizing radiation (’gama knife’ ablation) is used to cause the lesiosn. Lesions take time to develop. It is less invasive and does not need burr holes.
- Type of psychosurgery
- Anterior cingulotomy (ACING)
- Anterior capsulotomy (ACAPS)
- Subcaudate Tractotomy
- Limbic Leucotomy
- Indications for psychosurgery
- Sever, treatment-resistant OCD
- Severe, treatment-resistant Depression
- Adverse effects of psychosurgery
- Infection
- Hemorrhage
- Confusion
- Seizures
- Memory impairment
- Weight gain
- Urinary incontinence (temporary)
Other physical therapies
- Transcranial direct current stimulation (tDCS)
- Magnetic seizure therapy (MST)
- Direct cortical stimulation (DCS)
