Body Scan Versus Feeling Breath Overall

Whatever you make the spatial focus point for breath meditation, nose, middle of skull, belly, feet, all focal points can have pros and cons. In general, breath meditation is very safe to do, but people can have all kinds of unique and strange physical/mental health problems, so really any kind of meditation can 'cause', induce, or aggravate psychosis.

In general, people with hypertension, prone to headaches, by focusing on the nostril area, to the exclusion to the rest of the body, is going to tend to exacerbate those problems. Focusing on the entire body, every cell in the body, is in general going to be much more conducive to relaxation, pacification, bliss, leading into deeper states of meditation. And that's what the Buddha teaches in steps 3 and 4 of the 16 steps of breath meditation.

https://www.dhammatalks.org/books/WithEachAndEveryBreath/Contents.html

With Each & Every Breath A Guide To Meditation Thanissaro Bhikkhu (Geoffrey DeGraff)

The same site also has the book in various ebook formats (epub, mobi, etc.).

This is the best book available for a comprehensive guide on the topic of breath meditation, an authentic interpetation of the EBT (early buddhist texts).

If you overlook mindfulness of your body you run the risk of missing out on a lot of important self observations regarding the rupa and vedana skandhas (your bodily sensations and/or emotions). For that reason i'd recommend widening the scope of investigation.

The consecutive tetrads in anapanasati meditation provides a suggested framework for this, going from examining your breath, and further on to your body and so forth.

The full scope is covered in the anapanasati sutta.

The topic of Karma is only understood by a Buddha, but having said this I think if you have the karma to have a breakdown most probably this will happen if you meditate or not. The type of meditation may not play much of a factor as both are Vipssana type meditation. The probability can be lessened if you meditate.

There is some belief that doing Samatha meditation without a teacher and proper guidance may lead to breakdowns.

So finding a good teacher and having access to a teacher to clarify would diminish any possibility of break downs.

Part of breath meditation is mindfulness of the body. So is scanning the body. In this aspect, there is no difference in term of what frame of mindfulness (the type of sathipattana) is used.

In case you do not have a proper guide it is best that you take a course:

• http://dhamma.org
• http://www.internationalmeditationcentre.org

Just breathe. If you spend your meditation time worrying about how you are breathing, then you are not meditating.

"In-&-out breaths are bodily fabrications. "In-&-out breaths are bodily; these are things tied up with the body. That's why in-&-out breaths are bodily fabrications[sn41.006].

“On whatever occasion, bhikkhus, a bhikkhu, breathing in long, knows, ‘I breathe in long’; or breathing out long, knows, ‘I breathe out long’; breathing in short, knows, ‘I breathe in short’; or breathing out short, knows, ‘I breathe out short’; trains thus: ‘I shall breathe in experiencing the whole (breath) body’; trains thus, ‘I shall breathe out experiencing the whole (breath) body’; trains thus, ‘I shall breathe in calming the bodily formation;’ trains thus, ‘I shall breathe out calming the bodily formations’—on that occasion, bhikkhus, a bhikkhu abides contemplating the body in the body, ardent, clearly comprehending, mindful, having put away covetousness and grief regarding the world. “I say that this, bhikkhus, is a certain body among the bodies, namely, the breath. That is why on that occasion, bhikkhus, a bhikkhu abides contemplating the body in the body, clearly comprehending, mindful, having put away covetousness and grief regarding the world. [modified by me to make clear my preferred interpretation of mn118]

"In this way he remains focused internally on the body in & of itself, or externally on the body in & of itself, or both internally & externally on the body in & of itself. Or he remains focused on the phenomenon of origination with regard to the body, on the phenomenon of passing away with regard to the body, or on the phenomenon of origination & passing away with regard to the body. Or his mindfulness that 'There is a body' is maintained to the extent of knowledge & remembrance. And he remains independent, unsustained by (not clinging to) anything in the world. This is how a monk remains focused on the body in & of itself. (Satipatthana Sutta)

Person consists of 6 element; one of the six is wind element, in & out breaths are wind element.

"And what is the wind property? The wind property may be either internal or external. What is the internal wind property? Anything internal, belonging to oneself, that's wind, windy, & sustained: up-going winds, down-going winds, winds in the stomach, winds in the intestines, winds that course through the body, in-and-out breathing, or anything else internal, within oneself, that's wind, windy, & sustained: This is called the internal wind property. Now both the internal wind property & the external wind property are simply wind property. And that should be seen as it actually is present with right discernment: 'This is not mine, this is not me, this is not my self.' When one sees it thus as it actually is present with right discernment, one becomes disenchanted with the wind property and makes the wind property fade from the mind. (Mn140)

Based on my study of Buddhist texts, the guidance of my teachers, and my own experience - the most effective meditation (of this type) is to maintain awareness of the entire breath AND feelings, while releasing any mental/emotional blocks that you notice thanks to this awareness.

First of all, there is no magic in merely holding your attention - whether it is the tip of the nose or the diaphragm or abdomen or anything else. There is no magic button somewhere that will open some door if only you keep pushing, nothing like that.

Instead the key principle is to stop creating/maintaining trouble in your mental continuum. This is called "samatha". In order to stop creating/maintaining trouble we must notice it first. This is called "vipashyana". The better you see, the better you stop, the better you see.

When you watch the entire "body" of your inner experience, it is likely dominated by thoughts. This is expected in this era. There is another type of meditation for working with thoughts. But for this meditation you need to tune your awareness to predominantly watch everything but thoughts. This includes sensations of the body, the somatic components of emotions (the part of emotions felt in and around the body), and the emotional aspect of your mindstate (colloquially known as "the mood"). Sensations of the body include the muscle tonus, posture, and any acute neuroses manifesting in body shaking, tensions, or blocks. In the very center of this entire body of non-discursive experience is the cluster of sensations connected with breathing.

The breathing sits right on the intersection between physical and mental, which is what makes it special. If you center your awareness on the breathing, you will naturally include most of the bodily sensations on one side and most of the emotional aspect on the other side. This makes breathing a perfect focal point.

Specifically, it is the muscles involved in breathing in and breathing out. Because, if you watch carefully, you will notice that these muscles are extremely sensitive to all emotions. Any change in emotional "weather" results in the change of tension and affects the speed with which these muscles contract and relax. So by watching the state of muscles connected with breathing you can very clearly see your emotional state.

Once you learn to see the emotional state, you don't really have to focus on breathing. The point of all this exercise is not breathing, after all, it is perfection of samtha and vipashyana.

So the entire exercise of meditation is to watch all that, and to trace these blocks and neuroses to their emotional roots, so you can uproot them. This process of tracing may involve a little bit of thinking, but for the most part your job is to dwell on the feelings. The hangups are something you discover by seeing, not by reasoning.

Once you see them, you let them go, release them, dismiss them - whatever you want to call it. As said in the sutta, you watch your breathing in long, you watch your breathing out long, you watch your breathing in short, you watch your breathing out short, you watch your breathing while paying attention to the whole experience, you watch your breathing while relaxing the mind, you watch your breathing while gladdening the mind, you watch your breathing while liberating the mind.

This is not all there is to Buddhist meditation, and not all there is to Buddhism - but this is a big chunk. Just practicing this for a while (months? years?) will be of great benefit to most anyone.