'Else', not 'other'. 'Other' implies a comparison to something else within the sentence.
'Pursuit,' not 'pursue'. It's a noun, not a verb. I wouldn't use 'meanwhile,' as it implies something happening independently of the drugs, rather than as a result of them. 'Ended their lives earlier' implies an active involvement in the process, so I'd change that. You need an article before 'similar situation.' 'Precedents' implied you said something about football players dying in your essay already, and you'll want to pluralize or add an article to 'football player' ('footballer' seems a bit informal, though I could be wrong, not being a fan of football). Pluralize 'body,' as they don't have a collective body. I'm not sure why you decided to turn the person into an 'organism' -- I'd try to make this mesh a bit better with the rest of your essay. I'd turn your last sentence into 'can often be disastrous, even fatal,' as phrasing it the other way implies that it could be fatal, but what's worse, it could be disastrous! --which isn't your intent.
'Pop culture' is two words, and 'can' goes after the subjects ('fame and success'). 'One's' because it's a possessive, not a plural. Capitalize 'Spears,' and put a comma after your descriptive clause (ending after 'century'). You need to pluralize or add an article to 'rehabilitation course.'
'THE examples above,' otherwise it looks as though you're picking amongst your examples, instead of citing all of them, and 'it's' obvious. 'Thing' should be pluralized, and again it's 'pursuit,' not 'pursue.' A comma is need after 'unfortunately.'
I don't like the 5 paragraph format, but I think you could do with adding another paragraph of examples (how about the simple dream of being popular in your group of peers?), and you should either make your pop culture paragraph longer, or your sports one shorter, as it's unbalanced otherwise.
I hope I didn't seem too terse; I just didn't want to write an enormous wall of text -- but did it anyway.