1-T Tren caused a definite increase in aggression, irritability, and overreaction to stuff that would normally be a minor or moderate nuisance. My brother and mother who was visiting both independently said that I had been more touchy lately. I am naturally a litle irritable, and steroids do tend to amplify personality traits like this, but I have read about non-irritable people blowing up over little things on 1-T Tren (so I think there is some basis for it causing it, but everyone is different). When I came off, I was back to my old self and even I could notice the diff.
My libido was fine for the first 3 weeks and then the 75 year old woman syndrome came by and after 4 weeks of PCT, it is more or less back to normal. Supplementing with test would definitely help. I went from being a walking erection to not-even-qualified-to-be-called limp **** starting in week 3 of the cycle (and a beanie baby for balls of course).
The gains are indeed great.