well i knew someone who did this, and she did it secretly....while others do it for attention, the reason is most probably similar like everyone elses who hides it......depressed, seeking attention because of this or loneliness......but it needs too be reported, as this is some kind of an addiction.....one keeps on cutting it deeper with time....just like weed:D...the amonut of stuff keeps on increasing.........either help her out yrself or report it.
Self injury is far more "addictive," than weed. Not only does self injury cause a release of endorphins, it induces a state of disassociation and becomes a psychological band-aid for suppressing issues that the individual is unable or unwilling to deal with otherwise.
Girls are more inclined to self injure than males because of socialization. Men are taught it's ok to focus their anger on others (assertive), while women generally internalize their faults and blame themselves (submissive/self sacrificing behavior), this leads to female dominance in self injury. Instead of addressing the issue with the object/person a woman has the issue with, instead (whether it is due to self blaming behavior or not wanting to cause conflict), she punishes herself rather than punishing the other.
Physical pain makes the emotional pain disappear, for a short time. That's why cutters continue to cut. It only lasts so long, and the longer they do it, they more they need to do it, and the deeper they need to cut for the same effect. Generally these are very troubled people.