那个家伙突然在街上大喊大叫，像个疯子一样。

That guy started yelling in the street like a ___psycho.

他对心理学的兴趣始于大学时选修的一门心理课。

His interest in psychology started with a ___psycho course he took in college.

她对健身简直走火入魔，每天都要在健身房待五小时。

She's a total ___psycho about fitness, spending five hours at the gym every day.