• electroconvulsive therapy
• elderly
• effectiveness
• cognition
• adverse events
• major depression
• old age

Objective: Several variables have been studied as possible predictors for response to ECT; results from studies assessing the influence of age on ECT outcome in major depression reported controversial results. Since in older patients suffering from severe depression, ECT is often the treatment of choice, investigating the relationship between age and ECT outcome is considered relevant. Moreover, since age-specific adverse events such as greater cognitive impairment and higher somatic risks may be limiting factors in geriatric patients, we also investigated the relationship between age and ECT tolerability.
In this prospective naturalistic study, we compared clinical features, treatment outcomes and adverse events of young (18-45 years), middle-age (46 to 65 years), and old (65 years and older) patients treated with bilateral ECT for treatment-resistant major depression.
Method: The study was conducted in a cohort of 402 patients with treatment-resistant major depression who received ECT between January 2006 and April 2016 at the Department of Psychiatry of the University of Pisa. All patients were evaluated 1 day prior to ECT and a week after the treatment termination using the Clinical Global Impression Scale (CGI), the Hamilton Rating Scale for Depression-17 item (HAM-D-17), the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale (YMRS) and the Mini Mental State examination (MMSE). Adverse events were clinically monitored by the treating physician and the ECT psychiatrist during all the ECT course and finally registered on a four points scale. Demographic variables, clinical characteristics, short-term outcomes and rates of adverse events of the three age groups were compared. The influence of age on the attainment of response and remission was further analysed with logistic regression models.
Results: Old patients had the lowest percentage of males, highest ages of onset of any psychiatric illness, shorter lengths of current depressive episodes, higher baseline HAM-D-17 scores and lower baseline MMSE scores. Old patients underwent ECT courses characterized by shorter seizure durations and lower number of sessions. In the old group we observed the higher proportion of patients achieving response (69.6% versus 63.5% in young group and 55.5% in middle age group), but the differences were not statistically significant. No significant differences were detected in the proportions of remitters between the three age groups (31.4% in young group, 27.7% in middle age group and 29.3% in old group). Age as a continuous variable had no significant effect on the attainment of response and remission, adjusted for potential confounding factors. One week after the end of the ECT course all age groups showed an increase in the MMSE score compared to baseline, but the magnitude of such an increase was statistically significant only for the middle age and old groups. We did not detect significant differences between the three age groups nor in the proportions of patients reporting ECT-related adverse events either in premature drop-outs due to side effects.
Conclusion: The most surprising finding in our study was that old patients underwent shorter ECT courses; this finding is probably related to physician ‘s concerns about cognitive side effects in this group, leading to a tendency to stop the treatment as soon as possible. However, the risk of such a cautious approach is the under-treatment of old patients in clinical reality. We suggest that in the elderly, if the treatment is well tolerated, ECT should not be abandoned just because rapid response is not seen. Our results are in line with literature in indicating elderly patients treated with ECT as having a shorter duration of the current episode, which in turn is a predictor of a better responsivity to the treatment. We also confirm previous reports indicating late-life depression as frequently associated with cognitive impairment, which may resolve after ECT as a consequence of symptomatic improvement. Our data support previous studies indicating that ECT effectiveness is independent from age. We also found an excellent tolerability profile in the elderly in our patient sample. There was no mortality and no life-threatening adverse events.
Such results support the further use of ECT in elderly patients experiencing treatment-resistant major depression.