Objectives:
The aim of the study was to compare the occurrence of depressive symptoms between a group of patients with MPN (essential thrombocythemia, polycythemia vera, and primary myelofibrosis) treated with interferon-alpha and patients with chronic myelogenous leukaemia (CML) treated with tyrosine kinase inhibitors and to check whether individual side effects may contribute to the occurrence of depressive symptoms.

Methods:
The study involved 175 adult patients with MPN and CML who had been treated with IFNα or TKI for a minimum of 3 months. The study used: the David Goldberg Questionnaire (GHQ-28), the Four-Dimensional Questionnaire 4DSQ and our own survey.

Results:
Approximately 40% of patients with MPN and almost 20% of patients with CML obtained a moderately and strongly elevated score on the depression scale. The analysis revealed no statistically significant differences between women and men. Bone and joint pain (β=0.196, p=0.013), nausea and indigestion (β=0.191, p=0.007), fatigue (β=0.136, p=0.053), cramps and muscle aches (β=0.159, p=0.038) and diarrhoea (β=0.138, p=0.050) were side effects that affected the possibility of developing depressive symptoms in both groups. The common predictor of depressive symptoms was the number of side effects, the type of illness, and age. The older the person was, the greater the severity of depressive symptoms.

Conclusions:
There are significant differences in the prevalence of depression between patients with CML and MPN. Specific side effects of interferon-alpha and TKI treatment influence the occurrence of depressive symptoms. No association between interferon treatment and the development of depression was confirmed.