depression
"I was started on Mirtazapine at 16 after 5 years of Major Depression and suicidal ideation to the point where I was admitted into a psych ward 6 times for up to 5 weeks each time. I've tried Fluoxetine and Escitalopram and Mirtazapine has been the best. I felt happier and I wasn't as suicidal anymore which was a huge change. 
Warning though, as good as it is, be prepared to gain weight. I gained 10kg in six weeks and being already overweight I decided to discontinue its use and try something else."