Article summary of Cognitive therapy and interpersonal psychotherapy reduce suicidal ideation independent from their effect on depression by Van Bentum a.o. - 2021

What is this article about?

This article focuses on examining the effectiveness of Cognitive Therapy (CT) and Interpersonal Psychotherapy (IPT) on reducing suicidal ideation (SI) in the acute phase of Major Depressive Disorder (MDD). Suicide is a continuum, ranging from suicidal ideation to suicide attempts and death. Active treatments directly targeting suicidal behavior have shown some effectiveness, but clinical guidelines often focus on treating the primary psychiatric diagnosis, like MDD. Recent research suggests there is a relationship between depression and suicidality during treatments with results showing a decrease in suicidality is associated with a decrease in depression. However, theories on the nature of this relationship are still evolving.

This article has the following aims:

1. To assess whether CT and IPT are more effective than a wait-list control (WLC) in reducing SI among patients with MDD over an 8-week period.
2. To assess whether both CT and IPT could decrease SI independently of depression severity during therapy sessions, and whether one treatment is superior to the other in reducing SI.
3. To explore the temporal relationship between depressive symptoms and SI to examine whether changes in depressive symptoms precede changes in SI or vice versa.

What methods are used?

The study was part of a large RCT comparing CT and IPT to WLC for patients with MDD. Participants were recruited from a mental health center and underwent assessments of depression severity and SI. Only those scoring at least ≥1 on the self-report questionnaire BDI-II suicide item at baseline were included, resulting in a total sample size of 109 participants. These participants were seperated into the 3 groups: CT (n = 37), IPT (n = 54) and WLC (n = 18). Both CT and IPT consisted of 16-20 sessions. The primary outcome was severity of suicidality measured with the BDI-II suicide item score before each session. Mixed-effects analyses were used to examine treatment effects and the temporal relationship between depressive symptoms and SI. 

What are the results?

At baseline all BDI-II suicide item scores were low for all participants. There were no significant differences in sociodemographics between the CT, IPT and WLC group. After 8 weeks of treatment no significant improvement in suicide scores was found in the WLC group showing there was no spontaneous recovery in these participants. Additionally, after 8 weeks a significant larger improvement  in suicide scores was found in the CT and IPT groups compared to the WLC group. The mixed-effects model indicated that both CT and IPT led to significant reductions in suicidal ideation (SI) during treatment, with no differential effects between the two treatments. Results exploring the temporal relation between depressive symptoms and SI showed that SI measured at the previous session significantly predicted depressive symptoms at the current session.

What is the conclusion?

Both active treatments CT and IPT showed a larger decrease in SI in patients with MDD compared to patients in the WLC group. Additionally, these decreases in the CT and IPT group remained significant even after controlling for changes in overall depressive symptoms. No significant differences in effectiveness were observed between CT and IPT in reducing SI indicating comparable efficacy.

Furthermore, SI measured at the previous session predicted depressive symptoms at the current session, but depressive symptoms did not predict SI suggesting a unidirectional temporal relationship. These findings challenge the belief that treating depression will automatically reduce suicidal symptoms and underscore the importance of directly addressing SI in depressed patients.

Future research should validate these findings and explore potential long-term effects of CT and IPT on SI. Additionally, future studies should consider investigating the effects of these treatments on individuals with a wider range of SI severity and using multiple-item suicide assessment instruments to capture more nuanced changes in suicidal symptoms. Overall, these findings have important clinical implications, suggesting that addressing SI directly alongside depression may lead to more effective treatment outcomes in depressed individuals.