Hi I am due to start having treatment for PV, so far have just been having aspirin daily and venesections when needed. My haematological thinks it's time to start with treatment and I have been fortunate to have been offered the choice between the two. I am leaning towards interferon but am worried as I have always suffered with depression so it concerns me that this will worsen? Has anyone found this to be a major problem. I was also told they both lower our immune system, how concerning is this, would we need to avoid people with colds? Feeling very confused between the choice of the two at the moment.