Ive covered up a slue of mental problems for near 13 years of habitual use. Started drugs at 10, now 25 and the cleaner i get the more other troubles pop up mentally. It's a battle but the war of life is worth fighting every battle.
Yeah man, I know how that feels. I've only started using at 21 (I'm 26 now, 27 in a few days). It's not like I knew the mental issues weren't there, but stuff like GHB, amps, DXM and acid have been so helpful in working through them.
I went back to study at a university though, and this time I self-medicated myself through it and finished every course with good grades (talking top 10% here overall).
And now my second year is nearly halfway done and I'm just not feeling it. Same problems keep cropping up. It definitely doesn't help that I've started doing less drugs and that they took DXM off of the drug store shelves (pharmacies only now in my country).
I did less drugs during my last part of the school year as well and it fucked up my grades. But I don't want to have to pull off all kinds of drug use AND get enough sleep AND not fuck up my major AND not be too fucked up for my significant other. I just don't have enough time for all that stuff together, not unless they change the calendar so days last 30 hours instead of 24.
Ah, we can all wish.
Anyway, I'm going to see a shrink in a week. Hope they'll come up with a fitting diagnosis and for the first time, I'm open to being prescriped medication and therapy. I suspect I might be suffering from bipolar and/or attention defecit disorder; if anything, my drug use has improved the situation in some respects, especially my dissociative trips on DXM where I learned to see myself as others see me.
On the other hand, it might have caused me to seek professional help years later than if I hadn't been self-medicating. But maybe not, I can be a damn prideful person: I want to do everything myself.
On the level of cognitive impairment caused by drugs: it was mostly limiting beliefs and false ideas that I've held about the world around me and the people in it that have prevented me from functioning to the best of my abilities. I tend to overthink things, which can cause me to become very introverted at times, but not always. I can also be very extroverted when I am feeling good. The disinhibiting effects of GHB and DXM in particular have really changed me for the better in that respect, and I'm permanently more in tune with others and with my own emotions. So in that respect I have changed from a control freak who tells people what to do and bottles up his emotions to way more of a team player who can let his feelings flow through himself.
Sometimes I get asked if I'm worried about brain damage from all my DXM use - I'd say a couple hundred trips over the past 6 years (150-200 maybe?) - and I always say "It's totally been worth it." Because it has.
I know its easy to compare yourself to your sister but it doesnt mean there is anything innately 'wrong' with you, just that you have been exposed to an amout of dark shit and abuse with no-one to properly understand/protect you and whatever processes that took place within you, led you into gaping self destruction ...really hope things get better for you, from reading your posts can see that you are trying hard to fight this. Hope is always there, there are twists and turns but its always there to move ya forward. 
