The recent article on Mind and Life by Thomas Rocha "The Dark Knight" talks about how meditation can have negative effects for some people. This is a misconception, and the reason for which I wrote this article in which I explain that meditation IS NOT the cause of these negative effects, but is doing meditation in a WRONG WAY.
Can some people feel lost and confused when doing meditation? Sometimes this can happen when people start meditating by their own based on books and without any guidance. There are many misunderstandings about topics such as emptiness or the three marks of existence: impermanence, dissatisfaction, non-self. If someone meditates on these in the wrong way and for a long time they can become depressed and feel that everything is meaningless.
That's why it's so important to have:
1. A qualified teacher,
2. "Sangha" or spiritual friends, people who are on the same path who can support you.
3. Having a good balance of practices.
If someone meditates only on the no-self, the ego is going to feel threatened, or better said, fear and anxiety can arise. ego in the sense of grasping to a reified self. On the other hand there is the healthy Ego which some psychologist talk about. It's confusing to call it in the same way, because this is a sense of self esteem, confidence and acknowledging the existence of the self within conventional reality.
Some people who do meditation on non-self, miss the point that we DO exist...but how? in interdependence with all phenomena, in a state of flux, in dependence of causes and conditions, what we lack (are empty of) is an inherent existence, independent of all phenomena, this doesn't mean we don't exist at all!
It's very important to practice the Four Immeasurables (loving-kindness, compassion, empathetic joy and equanimity) to balance your Shamatha (attentional balance) and Vipashyana (insight) practices. Also, it's important to STUDY, REFLECT AND MEDITATE, and not only to do one of these.
For people who have a propensity towards developing psychotic disorders or who already have been diagnosed with these, it's very important to have proper psychological and/or psychiatric treatment before going into meditation. The main problem here is that during meditation all kinds of things can arise such as negative emotions, depressive thoughts, etc. because you are not distracted and not repressing. Psychotic people tend to believe and grasp to every thought, this intensifies the mental affliction.
As you can see, meditation IS NOT the cause, but is doing meditation in WRONG WAY.
The instruction is not to grasp to these experiences and let them go, not to reify them, if one follows the instruction, they will be pacified, liberated, non repressed, not reified. As long as one recognizes them as appearances, they have no power. On the contrary, If you get obsessed over a thought, emotion, sensation, etc. it will intensify. But this happen to people without meditation as well because they have severe imbalances that need medical treatment, and if you sit one of these persons to observe their minds for hours, and reflect on topics that challenge the way we understand reality, the consequences can be very negative.
Now, it's not like there are only two groups of people the healthy ones and the psychotic ones, we all have mental imbalances, our grasping, obsessions, internal chit chat and repetitive thoughts are experienced by all of us, so that's why we use meditation to balance our minds, with the proper guidance is very effective. If someone has more imbalances such as hearing voices, having visions, etc, they NEED Psychological treatment first, some of these might also need Psychiatric treatment. If the psychiatrist is also skilled in meditation, they might be able to lead them slowly to develop first loving kindness, compassion, towards themselves, and other suitable meditation practices and not put them to do practices such as emptiness, tantric visualizations and others that are not suitable for them.