Meditation is extremely helpful to people that suffer from ADHD, anxiety and stress-related problems. I have been using different yoga techniques for many years combining my training as a clinical psychologist, transpersonal therapist and a yoga teacher. As for depression and use of meditation I would be careful as it can be counterproductive. Some depressed people are already too much in their heads and meditation can just perpetuate that energy. There are few breathing techniques that help increase life energy which can be useful. Also combining positive imagery in meditation might help.
Within the context of mental health, in particular depression and anxiety, meditation should only - if at all - be used as part of a complete intervention, with qualified support. Without being embedded in such a context, trying to meditate can bring more harm than benefit.
For instance, secular mindfulness meditation, usually described as 'paying attention in an accepting, non-judging and curious way' includes the development of attention - but the important point is here, HOW one pays attention. If you start focusing more on your ruminations, catastrophysing thoughts etc this may be quite detrimental. To learn how to do this in the right way (non-judging, open, accepting, ...) requires careful guidance - even more so if a person suffers from anxiety or depression.
The empirical evidence regarding the effectiveness of Mindfulness-Based Cognitive Therapy (MBCT) for preventing the relapse of depression (after three or more depressive episodes) is relatively clear and accordingly the National Institute for Health and Care Excellence (NICE) in the UK recommends MBCT as treatment under these circumstances.
For acute depression the evidence is not yet as clear - but evidence in this direction starts building up to.
The main point I would like to stress is that it is not meditation on its own but embedded in a complete system offered by a qualified practitioner.
This is not only true in terms of a mental health intervention - but more generally. Meditation on its own is pretty pointless (I often think of it as a tool): you need to have an idea what to use it for and how to use it, to get any benefit out of it.
If you think of meditation in the buddhist context for instance, you will often here reference to: "view, meditation and action", i.e. meditation as part of a complete system including information (view) and application (action).
If you are interested, I recently shared a few thoughts about it in my meditation research blog:
Meditation & mental health care both walk in same line to view the beauty of nature which is the basic symptons of our line line as specially human being are undergoing an uncongenial on healthy environment .
The basic need of our present life demands peaceful atmosphere related to peaceful life.The power of meditation comes to our rescue..Care to be taken that meditation should not be working in the interval process when ever the need arises..it should be carry out regularly for the period of about 15 to 20 minutes .
Disturbing in your life in any areas place to us by depriving the peace of mind & this are the route cause of our regular cycle of our health put us the working of regular heart process-creating quite good diseases connected therewith .
In the process of meditation if practice the process of power of prayer it will certainly help us to offer a fragrance in our life..This will avoid Tension -Worries -& Frustration to keep our mind & quite.
I am glad to view your excellent in professional & my experience covering my help & guideline for my friends & well wishers to offer them a smiling face throu faith healing in their diseases which have become now days a common feature .