depression
"20 year old male.  After failing 2 of my college classes in one semester, decided it was time to do something about my increasing depression.  Doctor started me on Zoloft.  Took about 4 weeks to start to notice the effects.  Occasional shakes.  Memory loss was frequent.  Immediately noticed a decrease in sex drive and wasn't a problem until I started dating again and couldn't get it up the first time I got with my current girlfriend.  Luckily she is understanding.  My doctor is switching me to Wellbutrin.  If it wasn't for the decreased sex drive I probably would have stayed on it."