Disclaimer 

Meditation is a centuries old practice facilitating relaxation and stress management.  For some it is also a tool to enable spiritual development.  Meditation is not a substitute for those requiring psychological, psychiatric or medical care although the practice may be complementary under the correct conditions with professional supervision.

What the Science Says About Safety and Side Effects of Meditation*

Meditation is generally considered to be safe for healthy people.

Some research suggests that practicing meditation may reduce blood pressure, symptoms of irritable bowel syndrome, insomnia, anxiety and depression.

Some research suggests that meditation may physically change the brain and body and could potentially help to improve many health problems and promote healthy behaviors.  A 2013 review of three studies suggests that meditation may slow, stall, or even reverse changes that take place in the brain due to normal aging.

Do not use meditation to replace conventional care or as a reason to postpone seeing a health care provider about a medical problem.

There have been rare reports that meditation could cause or worsen symptoms in people with certain psychiatric problems.  People with existing mental health conditions should speak with their health care providers before starting a meditative practice.

* Source: National Center for Complementary and Integrative Health, 

part of the National Institute for Health  

Meditation and Mindfulness: What You Need To Know | NCCIH (nih.gov)