Edit: by personal statement I meant an essay segment in your application where you write about some difficult life experience that you have had to overcome and as a result have come out as a stronger/better individual. If a person has struggled with addiction to a substance (drugs including ethanol) and that experience very strongly afflicted his/her life for several months or longer, should that person mention this in his/her personal statement. Lets say the person is a friend that had an experience of cycles of functionality followed by inability to work, lack of affect, possibly depression. This person then did terribly for a semester but recovered and from the experience gained an immense amount of insight into addiction and certain mental states. I want to illustrate that the person had an extreme problem. The reason for at all bringing this up is that an extreme drop in academic performance occurred for the friend while in this period of addiction. Is this something that is safe to talk about with an adcom? Will it be taken against the applicant? How great of an influence will this have on the application?