I was once signed off for 6 weeks back in 2005 with stress and depression for something in my personal life. During that time I drove my car locally, and ran 2 red lights - I’d never done that before, and never done it since. Luckily no accidents occured. Another symptom I remember, was that I’d be on a road I’d driven down 500 times before, but wouldn’t feel any sense of familiarity with it, and felt as if I’d not been there before. The way it impacted me was very strange and unsettling. I definitely wasn’t fit to drive an HGV of a night time. The reason I decided to get signed off was because I had my first ever panic attack whilst overtaking an artic in my fully freighted artic on the M40 - it was frightening. Real stress is without doubt very harmful to one’s body and mind.