M20, recently started smoking. I haven't started any therapy or meds (I'm not even diagnosed with anything yet, I have my first consultation with the mental health and counseling services at my college in 2 weeks), so when I get pretty down or begin coming off of a high (just came off a 6 hour hypomanic episode) it's an easy way to cool myself down. Not sure why, but there's just something really comforting in the feeling of smoke filling up my lungs. Maybe it's also my inclination towards self harm.  
  
Anyway, any other smokers here? Why do you do it? Think it's related to BPD?