The practice of electroconvulsive therapy : aspects of efficacy and impact on cognitive function from population to polymorphism

ECT is the most effective treatment available for depression. Its usefulness is limited by side effects. The most commonly discussed side effect is cognitive dysfunction. This thesis investigates various aspects of ECT efficacy and the impact upon cognitive function. Using a clinical sample from the Royal Cornhill Hospital, Aberdeen, it was found that repeat courses of ECT are common. Repeated courses were as effective as single courses. On binary logistic regression psychotic symptoms at first treatment and lower MADRS score after first treatment predicted repeat courses. Lithium was underused to reduce relapse in the sample. ECT is prescribed to patients from different socioeconomic groups at a rate consistent with the population distribution in each socioeconomic quintile; ECT is not prescribed to patients from different socioeconomic groups at a rate consistent with the distribution of depression or severe depression in each quintile. Using the empirically determined seizure threshold a commonly used stimulus dosing protocol was compared with the half age method and a fixed by age method of ECT dosing. The fixed by age method was superior to stimulus dosing in terms of fewer stimulations, reduced cumulative electricity and fewer treatment sessions. More therapeutic seizures at first stimulus were achieved compared to the half age method. The CANTAB SRM was used to assess the cognitive function of patients during and after ECT. On this measure deficits were found up to three months following ECT but cognitive function had improved relative to baseline at six months. The MMSE was not sufficiently sensitive to detect change. Subjective memory correlated with mood score and the PRMQ was acceptable to patients. The val66met BDNF SNP and the val158met COMT SNP had no effect on cognitive function during the ECT process and up to three months of follow-up. Neither SNP affected ECT outcomes.