For patients with psychotic depression, response to treatment, remission rates, and cognitive improvement are better following electroconvulsive therapy (ECT) than for patients with nonpsychotic depression, results from a new study suggest.
However, findings from another study suggest that at least some of these differences may be because psychotic patients are referred for ECT earlier in the disease course.
Both studies were presented at the European Psychiatric Association 2020 Congress, which was held online this year because of the COVID-19 pandemic.
Limited, old evidence
The first study was led by Christopher Yi Wen Chan, MD, Institute of Mental Health, Singapore. The investigators stated that they have “often observed” superior remission rates with ECT in psychotic versus nonpsychotic depression. However, the evidence base is “limited and mostly more than 10 years old.”
They conducted a retrospective case-control study that included 160 patients – 50 with psychotic depression, and 110 with nonpsychotic depression. All patients had a primary diagnosis of unipolar major depressive disorder and underwent ECT at a tertiary psychiatric institute between January 2016 and January 2018.
Baseline characteristics of the two groups were similar, although patients with psychosis were more likely to have had an involuntary hospital admission and to have had higher baseline scores on the Montreal Cognitive Assessment (MoCA) and Clinical Global Impression–Severity scale (CGI-S) than nonpsychotic patients.
Response rates to ECT were significantly higher for the patients with psychotic depression than for those with nonpsychotic depression (79% vs. 51%; P = .009), as were remission rates (71% vs. 36%; P = .001).
Both groups showed significant improvement following ECT in Montgomery-Åsberg Depression Rating Scale, CGI, and quality-of-life scores.
However, only the participants with psychotic depression showed a significant improvement in MoCA total score (P = .038), as well as on attention (P = .024), language (P = .008), and orientation (P = .021) subdomains.
Psychotic depression markers?
For the second study, a team led by Aida De Arriba Arnau, MD, Centro de Investigación Biomédica en Red de Salud Mental, Barcelona, Spain, retrospectively analyzed 66 patients with depression who had received ECT. Of these, 26 had psychotic depression, and 40 had nonpsychotic depression.
Response rates were again higher in patients with psychotic vs nonpsychotic depression (92.3% vs. 85.0%). A similar number of sessions was needed to achieve a response.
Improvements in Hamilton Depression Rating Scale scores were significant between the two groups from the start of treatment, although the difference became nonsignificant at week 6.
Arriba Arnau said that there were some notable differences between patients with psychotic depression and those with nonpsychotic depression. For example, the former had “poor functionality, shorter episode duration, and less pharmacological resistance before receiving ECT,” she said.
“So we hypothesized that they might be referred more promptly to ECT treatment,” she added.
The psychotic depression group was significantly older than the group with nonpsychotic depression, at an average of 67.81 years vs 58.96 years.
They also “showed more illness severity and cognitive disturbances at baseline and ... required less anesthetic doses and higher initial stimulus intensity,» Arriba Arnau noted.
“All these features could be the markers of psychotic depression as an entity,” she said. However, the potential impact of age on these differences should be “further studied.”
She added that other aspects, such as age at onset and number of previous episodes, were similar between the groups.