Interestingly enough, yes stress can have an impact. I have had arthritis since I was young, but it wasn't until pregnant that I developed psoriasis on my hands. It came and went, sometimes worse than others. Fast forward 25 years later, the death of my mother triggered severe psoriasis on my feet. Which led to the actual diagnosis of psoriatic arthritis. By then my arthritis was severe, but started treatment and it keeps me mobile. Stressful events can certainly bring out symptoms.