The study will apply state of the art radiology through advanced magnetic resonance imaging (MRI) techniques to investigate structural and functional brain effects of ECT.

As a multi-disciplinary collaboration, imaging findings will be correlated to psychiatric response parameters, neuropsychological functioning as well as neurochemical and genetic biomarkers that can elucidate the underlying mechanisms. The aim is to document both treatment effects and potential harmful effects of ECT.

Sample: n = 40 patients in a major depressive episode (bipolar and major depressive disorder). Two control groups with n = 15 in each group: age and gender matched healthy volunteers not receiving ECT and patients undergoing electrical cardioversion (ECV) for atrial fibrillation (AF). Observation time: six months.

Inclusion Criteria:

• Patients (age > 18) referred to the ECT-unit and accepted for treatment because of moderate and severe depression,
• fulfilling the criteria for the following ICD-10 diagnoses: F31.3 and F31.4; F32.1 and F32.2 and F32.3; F33.1 and F33.2 and F33.3.
• symptom intensity must be verified by a score ≥ 25 on the Montgomery and Åsberg Depression Rating Scale (MADRS).

Exclusion Criteria:

• ECT treatment within the last 12 months.
• Pregnancy.
• Patients unable to give written informed consent (according to the responsible clinician or ECT responsible).
• Patients who cannot participate in the MRI scanning because of contraindications to MRI.

Forty patients accepted for ECT at Haukeland University Hospital will be included.

Control groups: A group of patients undergoing Electrocardioversion (ECV) for atrial fibrilation (AF) (controls 1) and healthy controls undergoing the same investigations as the ECT patient group, but not receiving ECT or anesthesia (controls 2).