Contra-Indications to Mindful Meditation Practice
In very rare cases there have been studies that have shown that some people experience negative effects such as dissociation, anxiety, depression and hallucinations when practising mindful meditation extensively. The people most susceptible to these side effects are people who are mentally vulnerable for example, schizophrenic patients, people who have long term mental health issues and in some cases, people who have experienced PTSD. It is important to be taught meditation by an experienced teacher and in a safe environment.
You should not practice Mindful Meditation if you are under the influence of drugs or alcohol.