Two hits had an unpredictable effect. Obviously, because ecstasy is illegal, you never know what you are buying. Some of the recent coverage has claimed that 20 to 40 percent of the ecstasy sold at raves and in clubs contains something other than MDMA. Sometimes two pills produced an agreeable high akin to my first ecstasy experiences. Other times, I felt much higher than I wanted, as well as nauseated and mildly paranoid.

Not surprisingly, as my use of the drug increased, so did the subsequent depression. Frequently, it lasted two or three days instead of one. I began to feel lost, and afraid. Also present was an undercurrent of insecurity: I constantly questioned myself. While none of the details of my life had changed -- my career was still clipping along at an impressive rate, my relationship with my husband was thriving and the friendships I'd made through ecstasy were still solid and rewarding -- I felt increasingly unhinged.

During this time, a conversation I had with a friend was inadvertently recorded on my answering machine. When I played it back, I was jolted. "Do you know what I mean?" I asked, after everything I said. It was as if I was obsessively questioning whether anyone could relate to me, and whether I might be just a bit crazy.

The truth was, I didn't feel as if anyone understood how I felt, and I was terrified to admit this to the people close to me. I was afraid they'd tell me to stop taking ecstasy and I didn't want to stop. I simply didn't want to miss the party.

Everything I have read about ecstasy claims that it is not physically addictive. That may be true -- but I'd argue that I was hooked on the emotional high of clubbing, that I was hooked on the experiences I was having while taking ecstasy rather than on the drug itself. I refused to give that up, no matter how low, or strange, I felt afterward.

Finally, one night I took two hits of ecstasy stronger than any I'd ever used. I had grotesque hallucinations. People on the dance floor looked like aliens out of a nightmarish sci-fi movie, their eyes hollow and ringed in black. When I tried to sleep later that night, pornographic images flashed through my brain. I saw bloated, floating penises penetrating gaping orifices, which turned into tunnels that slid and twisted. Whenever I opened my eyes, I welcomed the tame reality of the ceiling of my apartment. I wondered if I had actually taken DXM, a cheap cough suppressant that is sometimes substituted for MDMA and causes hallucinations in the 130-milligram dose usually found in fake ecstasy (13 times the amount in a dose of Robitussin).

I spent the next week trying not to drown in my depression. I suddenly understood "the black wave" Elizabeth Wurtzel describes in "Prozac Nation," her poignant memoir of depression. Dark emotions, highlighted by self-loathing and severe anxiety, crashed down on me. I could do nothing to move out of their way. (While Wurtzel makes clear her depression was organic, she also explains that she and two friends were known at Harvard as "the Ecstasy Goddesses" because of their excessive use of the drug.)

I stayed home from work. I spent most of the next few days in bed, crying nearly nonstop. I refused to answer the phone, even when I suspected it was my panicked husband checking on me. I felt that I couldn't communicate to anyone the depth of my sadness, so why try? I sensed that my thoughts were irrational -- I instinctively understood that the desperation I felt came from a chemical imbalance in my brain. But that awareness did nothing to ease my distress.

Only when I finally told my husband how I was feeling did the knowledge click. I sobbed off and on for hours, confessing the details of my depression. I realized that this drug I had swallowed to lift myself to euphoria was ultimately sending me crashing back down, to a lower, more frightening level than I'd ever known, or would have experienced if I'd stayed sober. With that realization, I gave up ecstasy.

It took several weeks for me to start feeling normal again. During that time, I was tempted to take ecstasy again. Once, at midnight, when friends were heading out to a club, I called my husband and had to be talked out of following. In the morning, I was relieved that I hadn't gone. It felt fantastic not to be hung over and exhausted. That gloriously fresh Sunday inspired me to stay away from ecstasy indefinitely.

Now, with all the media attention to the joys of ecstasy, I find myself in the peculiar position of cheering the messengers while feeling wary about the drug. I saw "Groove" on opening night in San Francisco, and I loved it. The rave scene can be inspiring and invigorating. I applaud Harrison for depicting it honestly and accurately.

But I no longer believe that ecstasy is benign. When I look around at the people I know who take it regularly, it doesn't seem coincidental that many of them are profoundly unhappy. The depression that follows regular ecstasy use isn't trivial and shouldn't be dismissed. I've always believed that the U.S. government is hypocritical for outlawing substances like ecstasy and marijuana while sanctioning drugs like alcohol and nicotine. I considered booze and cigarettes to be far more dangerous than pot. Now I wonder whether the claim that ecstasy is "the new beer" is more apt, and chilling, than I realized.

Thursday: Crackdown on club drugs: Legislation in Congress would make it a crime to distribute information on ecstasy and other illegal substances.

Sign up to receive free e-mail updates from Salon -- now in 17 different varieties!