Effects of Psychological Interventions on Depression Symptoms in Oncology Patients: A Systematic Review.

Background: Depression is one of the most common psychological comorbidities among cancer patients and contributes substantially to a reduced quality of life and impaired treatment adherence. A range of psychosocial interventions have been proposed to address depressive symptoms in oncology, but evidence across intervention types remains heterogeneous. Aim: To evaluate the effectiveness of psychological interventions in reducing depressive symptoms among cancer patients. Methods: A systematic search of Results: Twenty studies met the inclusion criteria. Interventions included cognitive behavioural therapy (CBT), mindfulness-based interventions (MBIs), mindfulness-based stress reduction (MBSR), mindfulness-based cognitive therapy (MBCT), and positive psychology approaches. Most studies reported significant reductions in depressive symptoms measured by using validated scales such as PHQ-9, HADS, BDI, and SDS. CBT- and mindfulness-based approaches demonstrated the most consistent improvements, although several trials reported no significant differences compared with control groups. Conclusions: Psychological interventions, and particularly CBT- and mindfulness-based approaches, are associated with reductions in depressive symptoms among cancer patients. However, substantial heterogeneity in the intervention design and outcome reporting limits direct comparison across studies. Further large-scale randomized trials using standardised outcome measures are needed to establish optimal psychosocial treatment strategies in oncology.