your age, occupation and other symptoms are missing in the clinical information
Anyway MIld Depression
usually wont last for continuous fie years. Dysthymia
can last for 5years
If you find depression after starting on inderal
consult your physician and discuss about the possible contributions.
if it was found to be independent of inderal use then meet your nearest psychiatrist
for CBT sessions.
Usually Mild depression get improve by CBT alone without taking antidepressents depending on your level of dysfunction.
My best wishes to get well soon.