I know when I'm really depressed I cancel every appointment. I decide I don't need it because what's the point? If I truly don't care about myself, then why take care of myself?

I'm not a doctor and I can't tell you if your friend's in a similar boat as me or anyone with MI. Maybe encourage your friend to seek out some help from a therapist or counselor. More than that, just be there for them and maybe you can help them work through it (but don't quit taking care of yourself in the process).