I have had a similar thing with eyebrows but just found out about trichotillomania today - I knew there was something where people pulled out their head hair but didn't ever think of my habit in this way. My family tease me about it but it's something I can't control and I have more than I used to at the moment but they did fall out a lot, probably more in times of stress. I remember seeing them all over exam papers. It's still really irritating, like when I am trying to study but my hand has to be on my eyebrows. I'm not sure why it started but having read some stuff today, I think I might ask the doctor. It's gone on for about 4 years probably, I've always had OCD type tendencies and I think it began around the time I developed an eating disorder (this is gone now) but I also experience a lot of symptoms of depression, which trichotillomania is apparently secondary too sometimes. I'm not sure this post is helpful but it's reassuring to hear that someone else is experiencing the same as you - people always just think I'm weird and don't understand I can't control it (and I try to hide it from friends as I get embarrassed, but it can be hard). Good luck with everything