Long term effect of Continuation Electroconvulsive therapy

Depression is a disease that affects a large part of the population, every year about 4.6–7.0% of the population is affected by the disease at some point. One way to treat major depression is with electroconvulsive therapy (ECT). In ECT, electric shocks are given via contact points on the patient's skull, causing the patient to have convulsions similar to an epileptic seizure. ECT is a very effective treatment for depression and often works even after several medications have been tested without reducing the symptoms of depression.

Many people who get better after treatment for depression, whether it is medication or ECT, later regain symptoms of the disease. To prevent the disease from returning, continued treatment is used, mainly medication but also continued ECT can be given but then at longer intervals between treatments.

A randomized study from 2012 showed that continued treatment for one year with medication and ECT provided better protection against new depression than medication alone. We now want to investigate whether the results from the 2012 study stood even after the patients stopped receiving ECT. The primary purpose of the study is to investigate how continuation ECT after index ECT for depression affects the effect of relapse after continuation ECT is completed. A secondary purpose is to investigate what treatment the patients have had. Through register data from national registers such as the patient register, the cause of death register, the drug register, and the Quality Register ECT, we can investigate whether and when patients developed a new depression, and what treatment was given. Through the register data, information at the individual level can be identified. Then we can investigate whether at the group level there is any difference between the patients who were treated with medication and ECT regarding how they coped with depression compared to those who only received medication.