Vipassana-style meditation has been adapted to treat patients to prevent recurrence of depression and anxiety through MBCT, and to treat chronic pain and stress through MBSR. More info on this can found in this answer.
On the other hand, there have been some reported cases (see here) of people who attended the 10-day Goenka vipassana retreats and became psychotic and suicidal.
I have also heard that such negative effects may be a normal part of a meditator's progress, called the "dark night" or "death of the ego" (according to this answer). These could be part of the sixteen stages of insight (according to this page), namely bhaya nana or "knowledge of the appearance as terror" and adinava nana or "knowledge of the contemplation of disadvantages".
- Are episodes of psychosis resulting from 10-day vipassana retreats the result of something not right (e.g. pre-existing mental conditions, the side effect of combining other techniques such as mantra or tantra with vipassana), or is it a normal part of progress in vipassana meditation? If the two are different, then what is the difference?
- For lay people, are the Goenka retreats considered too intense and thus out-of-moderation? Is it better for lay people to attend weekly sessions and spend less than an hour daily in meditation, rather than the intense and rigorous Goenka retreats?
- Is it better for lay people to practise in such a way that they will not reach the "dark night" stages because these stages are more suited for monks?
- Is it required for lay people to find a teacher who can determine what is moderate for them, or can they just follow generic instructions?