Editor's note: Don't miss "Weed 2: Cannabis Madness: Dr. Sanjay Gupta Reports," at 10 p.m. ET on Tuesday. Also, Dr. Gupta will be answering your questions on Reddit at noon ET Friday.
(CNN) -- It's been eight months since I last wrote about medical marijuana, apologizing for having not dug deeply into the beneficial effects of this plant and for writing articles dismissing its potential. I apologized for my own role in previously misleading people, and I feel very badly that people have suffered for too long, unable to obtain the legitimate medicine that may have helped them.
I have been reminded that a true and productive scientific journey involves a willingness to let go of established notions and get at the truth, even if it is uncomfortable and even it means having to say "sorry."
It is not easy to apologize and take your lumps, but this was never about me.
This scientific journey is about a growing number of patients who want the cannabis plant as a genuine medicine, not to get high.
It is about emerging science that not only shows and proves what marijuana can do for the body but provides better insights into the mechanisms of marijuana in the brain, helping us better understand a plant whose benefits have been documented for thousands of years. This journey is also about a Draconian system where politics override science and patients are caught in the middle.
Since our documentary "Weed" aired in August, I have continued to travel the world, investigating and asking tough questions about marijuana.
I have met with hundreds of patients, dozens of scientists and the curious majority who simply want a deeper understanding of this ancient plant. I have sat in labs and personally analyzed the molecules in marijuana that have such potential but are also a source of intense controversy. I have seen those molecules turned into medicine that has quelled epilepsy in a child and pain in a grown adult. I've seen it help a woman at the peak of her life to overcome the ravages of multiple sclerosis.