Each investor has his/her own situation to take into account, and as you have observed, stress management is part of that equation.
I am in the desirable situation such that if AVXL goes to 0 tomorrow morning my life style will not change. If it goes up to anywhere close to the more modest predictions I will have many more options available to me.
I am reminded of Buffet's comment. "“Wait for a fat pitch and then swing for the fences.”
I see ANAVEX as that fat pitch. That's just me. YMMV.