A reader writes:

Since I was a teenager I've struggled with bipolar disorder. In the worst craters of depression I've driven myself to starvation and self-mutilation. I've attempted suicide twice. Traditional therapy never worked because I never gave it a chance. I'm an arrogant and defensive son of a bitch, and self-indulgently preferred my private masochism over admitting I needed help. After one particularly bad incident that landed me in the ER, I was prescribed a standard for-profit mood stabilizer. After a few days I threw it away. Cannabis discovered me one evening my senior year of college.

At first I was underwhelmed. But those weed-lubricated gatherings of wannabe-writers and pseudointellectuals steadily increased in frequency until they were almost nightly. Somewhere along the line I woke up one morning, and my first thought was not to hope I'd be involved in a fatal car accident that day. From then on I was hooked.

Today I'm a very successful web entrepreneur. I've never had a boss. I have employees on three continents and netted a robust six figures last year. This year I'll make more. Several months ago I got engaged and we bought a five-bedroom house in the inner DC suburbs. We adopted two abuse-rescue dogs that we're slowly nursing back to health. I'm extremely active in local politics and was an Obama precinct captain during the election. Once a week I teach a cooking class to kids at our church. I'm 25 years old. And I get high twice a day.

Am I psychologically dependent on pot? Probably. Am I a textbook case of irresponsible self-medication? Almost certainly. But can someone please tell me what the harm is? I use a vaporizer and take antioxidant supplements to mitigate (somewhat) the cancer risk. I buy my pot from another nondescript suburban guy who has a small grow closet in his basement. My drug money does not finance international terrorism. I smoke alone, with the shades drawn, and never drive under the influence. I have never taken any other illegal drugs. I have never broken any other laws.

Marijuana gives me a balance I've been unable to find anywhere else in life. It is much, much cheaper than a therapist and prescription antidepressants. It has allowed me to function normally - in a weak moment I might even say quite admirably - for the past several years, whereas without it I do not doubt for a second I would've eventually attempted suicide again.