ECT, rTMS, chronobiology

ECT

electro-shock treatment, being the most effective therapy in psychiatry (71-94% efficacy in MDD):

- MA: ECT provokes an epileptic paroxysm via electric stimulation (over several day-long intervals) stimulating dopaminergic transmission, GABA and β-endorphines. The procedure is done under anesthesia (propofol anesthetic + succinylcholine for myorelaxation) and pre-treatment with an anticholinergic (e.g. atropine) to prevent cardiac bradyarrhythmias or aspiration is recommended. Treatment is continued till the patient achieves maximum therapeutic response (>20s EEG seizure!)

- Indications: depression (pharmacoresistant, psychotic depression or MDD in 🤰 ), manic schizoaffective disorder, symptomatic psychosis, schizophrenia (catatonic or with psychomotor agitation), lethal catatonia (bilateral approach), NMS (from severe EPS);

- CIs: intracranial HT, CNS tumour/aneurysm, CNS post-hemorrhage, demyelination, retinal detachment, pheochromocytoma, anesthesiological hazards (concomitant infection), post-infarction;

- AEs: confusion, memory loss (rare & disappearing after ≈ 3m);- Procedure (takes ≈ 20 minutes): treatment of MDD usually takes ≈ 6-8 sessions, whereas mania and schizophrenia take ≈ 8-12 sessions; Tonic phase (during shock delivery) → clonic phase (immediately after shock);

rTMS (repetitive transcranial magnetic stimulation)

Non-invasive technique used to excite neutrons in the brain as weak electric currents are induced in the neurons by rapidly changing magnetic fields:

- Indication: major depression (coils in dorsolateral prefrontal cortex) + tinnitus + NMS; - CI: history of epilepsy, intracranial HT, usage of drugs ↓ seizure threshold, history of stroke or a pathological EEG;

- AEs: induction of epileptic paroxysm, headache during application, temporary ↑ seizure threshold; Vagus nerve stimulation: invasive method, used mainly for resistant epilepsy (after ECT has failed);

- AEs: alteration of voice, coughing, throat pain, hoarseness, ↓ HR, obstructive sleep apnea (reversible); DBS → only used for resistant OCD (also for intention tremor and PD);

Chronobiology

A branch of biology concerned with cyclical physiological phenomena:

• Biological timing system: central (suprachiasmatic nuclei) and peripheral clocks (every organ/cell);
• Zeitgebers (Synchronising agents): reset and stabilise central/peripheral clocks: light/dark cycle (blue light is the major one → melatonin from pineal gland), social cues, mealtimes, exercise, …
• Experiences in mices with clock mutations (polygenetic) manifest ↑ similar behavior to human mania! • Daily and seasonal cycles affect many aspects of mental illness:
  • Depression is linked to diurnal mood variation, early morning awakening, longer-term periodicities (manic-depressive cycles) or seasonally linked episodes; Sleep deprivation may reveal ↑ effective!
  • Seasonal affective disorder: may be treated with phototherapy