An interesting discussion "Meditation as medication" between Robert Wright (Bloggingheads.tv, The Evolution of God, Nonzero) and Miguel Farias (Coventry University, The Buddha Pill) on the possible negative and positive effects of meditation. I think calling meditation effects positive or negative (or similar comparative adjectives) is something we shouldn't do. I think the whole point of meditation is to explore what the meditation experience is like for you. It is not bad or good, it is just an experience.
What we should remember about meditation is that as the famous quote says: “with great knowledge comes great responsibility” to everyone around us and to ourselves. Meditation doesn’t guarantee you will experience only good or bad things. Bad or good do not exist in Buddhism to begin with. There is no universal formula to attain liberation from suffering. There are only suggestions how to attain it. Buddha says you are the final authority to judge if it works for you.
I have been practicing with Zen for some years as well as Vipassana more recently. Zen emphasizes you should not share your experiences with anyone but your teacher. I couldn’t understand that for a long time, but now I see the benefits of it. Now, after four years of Zen practice, I started to share my experience with other and it helps my practice. However, with more practice I start seeing why Zen approach might be much more useful at least at the beginning of your practice. Zen tradition recognizes that your individual experiences are key and listening to other people experience might contaminate to your practice.
Not every practice is going to work for everyone and there is a not universal formula. However despite which tradition you choose to follow, what they all have in common the emphasis on the fact that you have a choice how you relate to our experiences. You have to discover for yourself what works for you. That is why there are so many traditions to begging with. Mindfulness is just one of the tools; for some it works and for some it doesn’t. I have no idea why in Western culture mindfulness is so popular in comparison with Zen or Tibetan tradition. Perhaps mindfulness has the less religious aspect to it and this attracts Westerners, but it is not a universal solution to every Westerner as it is sometimes presented. However, independent of tradition, a good teacher (in any tradition) will be pointing out that individual experiences and your response to them are what matters and all advice you get is only a guideline. You are the one who makes the final decision.
It always puzzled me why do we expect that meditation will bring only good experiences? As Robert Wright says in the video some people come to meditation with a very troubled mind to begin with. If you are troubled from the beginning why would you expect only good things will come out? Even if your mind is not troubled, you still will experience difficult feelings during the meditation (some bigger or smaller, but bad things happen to everyone). In meditation, you will be put face to face with those experiences and you have no place to run. But here you need to ask yourself, why are you meditating? I agree with James Baraz that your meditation intention is extremely important. If your intention is to feel calm, I bet that when you experience for example an intense fear during meditation, it is very likely you will (to put it very bluntly) freak out. If your intention is to become wiser, then you might explore this fear and stay with it to understand it.
I agree that a good teacher is very important. As Robert says a good teacher for you might be a complete disaster for me. You need to find someone who resonates with you. A teacher there is to guide your practice. A teacher will tell you that meditation doesn’t guarantee you only good or bad experiences; the teacher will guide you to see all these emotions (or anything that arise during your meditation) for what they are. In meditation, you will learn to incline your mind towards being with that emotion and choosing your reaction to it. If someone has terrible experience during the meditation and ends up with for example a depression, maybe that means that person for the first time became aware of it and hopefully will be able to seek necessary help, if meditation doesn’t do the job. We can't however, claim that meditation per se causes depression, but of course, this is a possibility. Experimental studies should help to answer this question. A good teacher and remembering why you meditate could also help in such situations.
I am not knowledgeable enough to argue why people might commit suicide after the retreat. It is really sad to hear such things happen. However, I think before we draw definite conclusions in such cases we again need to examine them by taking into account many different co-founding factors. It is also important to keep in mind that in certain cases intensive retreat is not necessary the best thing to start your meditation practice with. At least in Zen tradition, you might not be advised to go to a retreat for a long time. Sometimes some people might benefit more from a regular sitting at home.
We sometimes feel the need to meditate, but haven't yet fully understood why we want to do it. I think at least in Western culture we want to get the benefits of meditation immediately (today's "marketing" of meditation benefits makes people crave those immediate benefits), without fully understanding that a part of meditation is facing your very deep fears and very negative emotions. Some of these emotions we are not even aware of before we start exploring them. Meditation is a very hard work and a very long process before you start seeing any benefits at all. There are a lot of warnings in older Buddhist text what meditation can do to you if your mind is not ready. Before you start your meditation practice, ask yourself what your motivation to do the meditation is? Meditation can and will bring bad experiences as well as good ones.
Perhaps there was a very good reason why meditation was kept for monks only for a long time (and still is in some countries). Now, when it becomes available to everyone, it is more than ever important to ask yourself are you ready to discover what might be hiding in the deepest realms of your minds? If your aim is just to be more relaxed, perhaps going to intensive retreat to explore the darkest corners of your mind is not necessary the most beneficial thing to do, at least not at the beginning of your practice. The mind is a big mystery and trying to explore it can be a very difficult journey. I agree that meditation can have good and bad sides, but it is like everything else. Most of us coffee keep awake, but there are people who don’t experience such effect and feel sleepy after a cup of coffee. Thus, we can’t claim that drinking coffee will prevent everyone from sleeping. It is the same with meditation. After all, it is all your own experience, it is not good or bad, it is a personal one and with practice, you learn to know what it is for you. Saying that meditation will help or harm someone is the same as denying a need to meditate. The motivation to do or not to do should come from within. The only thing we can do as practitioners is to share our personal experience and let other people decide to if they want to follow the Buddha path.
