Throughout highschool I was one of those 'moody teenagers' who oscillated between depression and normality. I went nowhere near even the most conventional drug use. When I got to college, I experienced anxiety and depression and was prescribed Lexapro (escitalopram), the SSRI antidepressant, at 10mg.
Fast-forward: two months later I suddenly experienced an increase in energy, mind-expansion, and general self-confidence to the point of obnoxiousness (to others). About two weeks into it, I happened to be in India, and a friend who had recently begun using hashish offered to share a joint. Being in an already altered state of mind, I accepted.
I almost immediately blacked out; the hash was that strong. Most people talk about not really getting stoned their first time, but I most definitely was, to the point of having visual distortion and some dissociation. Well, I purchased several tolas (a tola is 10g in India), smoked for four days straight, and boarded a plane from India to Britain to the States with about 10g of hash in my luggage and a gram of opium on me.
The next six weeks or so, my mood continued to escalate; marijuana didn't help me calm down, either. Instead of making me foggy, forgetful and sleepy it acted like a stimulant, keeping me up till 6am every time I smoked. Eventually I snapped after staying up for several days, crashed into depression.
I was diagnosed with bipolar disorder, and am now on six prescription medications to keep me stable. I guess it had always been there, latent, but the antidepressant kicked me off into mania and the hashish definitely exacerbated it. I don't know what would happen to me if I smoked while depressed. I have stayed away from weed in all forms since my breakdown (although I have tried several other things).
I am not opposed to drug use, and I wholeheartedly think most drugs should be made legal. But I think if there's a moral to my story, it's this: Know your family history (my grandma is also bipolar), beware of any instability, because drugs can definitely bring out or exacerbate mental problems. Lastly, never underestimate the power of a single experience to change the course of your life.