Temporal and specific pathways of change in cognitive behavioral therapy (CBT) and interpersonal psychotherapy (IPT) for depression

Sanne J E Bruijniks*, Martijn Meeter, Lotte H J M Lemmens, Frenk Peeters, Pim Cuijpers, Marcus J H Huibers

*Corresponding author for this work

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BACKGROUND: The present study investigated the specific and temporal role of putative mechanisms of change in cognitive-behavioral therapy (CBT) and interpersonal psychotherapy (IPT) for major depressive disorder (MDD).

METHOD: 200 patients were randomized to CBT weekly, CBT twice weekly, IPT weekly or IPT twice weekly. Outcome and putative mechanisms of change (i.e., dysfunctional thinking, behavioral activation, CBT skills, IPT skills, therapeutic alliance, compliance, motivation) were measured multiple times up to six months after the start of treatment. Latent change score models were used to investigate temporal relations and test mediation. Explorative analyses tested whether baseline working memory moderated the effect of mechanism change on outcome change.

RESULTS: CBT skills and dysfunctional thinking mediated the relation between treatment modality and changes in depression. In both treatments, IPT skills and behavioral activation were related to subsequent change in depression while a decrease in depression led to subsequent improvement in therapeutic alliance and a decrease in autonomous motivation. Change in compliance was unrelated to change in depression. Baseline working memory was related to therapy skill improvement.

CONCLUSION: CBT skill improvement seems a specific mechanism of change leading to subsequent decrease in depression in CBT. Changes in IPT skills acted as a non-specific mechanism, subsequently reducing depression regardless of treatment modality. The specific role of cognitive change and behavioral activation remains unclear. Future studies should investigate the specificity and direction of the potential mechanisms of change throughout the course of therapy and investigate whether these mechanistic pathways differ between individuals.

Original languageEnglish
Article number104010
Number of pages13
JournalBehaviour Research and Therapy
Early online date27 Nov 2021
Publication statusPublished - Apr 2022


  • Depression
  • Mechanisms of change
  • Cognitive-behavioral therapy
  • Interpersonal psychotherapy
  • Therapy skills
  • Cognitive change

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