Studies have demonstrated a positive association between self-reported mindfulness and self-reported positive affect. It also appears that mindfulness training can increase positive affect, although much more research has focused on the effects on negative affect (e.g., depression, stress, anxiety).

There are many ways to build positive affect. One simple strategy is appreciating things that are already happening. We often overlook many positive moments that occur during the day, but intentionally savoring these can increase positive affect. Social connection is another powerful way to increase positive affect as is physical exercise. There is evidence that various meditative practices (e.g., mindfulness, lovingkindness, compassion) can also increase positive affect.

There is evidence that mindfulness training can increase positive affect, although much more research has examined reductions in negative affect. Trait mindfulness assessed by self-report measures have shown positive associations with positive affect.

Here are relevant scientific papers:

https://www.frontiersin.org/articles/10.3389/fpsyg.2015.00015/full

https://link.springer.com/article/10.1007/s12671-016-0568-y

There are a number of mechanisms that have been proposed. These include decreased emotional reactivity, increased self-compassion, increased attention regulation, and changes in how one views the self. This is an area of active research, and a variety of mechanisms continue to be explored.

If you're interested in reading more, I suggest the following scientific papers:

https://pubmed.ncbi.nlm.nih.gov/26168376/

https://pubmed.ncbi.nlm.nih.gov/25689576/

https://pubmed.ncbi.nlm.nih.gov/30525995/

It's true that not everyone will benefit from mindfulness practices and that many individuals may find mindfulness practice very unpleasant and/or unhelpful. That said, a large body of evidence suggests that, on average, individuals participating in mindfulness-based interventions show reductions in negative affect (e.g., depression, anxiety, stress). Individuals who are experiencing high levels of negative affect may stand to benefit more from practice (i.e., they have symptoms which could be reduced).

In the general population, it appears that individuals who are experiencing depressive symptoms are more likely to practice meditation:

https://bmccomplementmedtherapies.biomedcentral.com/articles/10.1186/s12906-017-1827-8

There are various opinions about the key ingredients of mindfulness training, but most would agree that cultivation of nonjudgmental awareness in the present moment is central. This can certainly happen with breath awareness. And one can learn a lot simply from trying to attend to the breath mindfully (i.e., it may not be necessary to engage in another style of practice to benefit). The association between length of practice per day and outcomes has not been established. There is some indication that practicing more is more helpful, but this is an active area of research.

Here is a relevant study:

https://pubmed.ncbi.nlm.nih.gov/28527330/

Many individuals find mindfulness challenging, especially at first. You could try exploring ways of incorporating mindfulness into activities (e.g., mindful walking, mindful eating). You also might explore other forms of meditation practice, such as lovingkindness or compassion practices.

Here's a link to a free mobile app that includes mindfulness practices (awareness) as well as lovingkindness practices (connection): https://hminnovations.org/meditation-app

Interestingly, the very first mindfulness-based intervention tested in the Western scientific literature (mindfulness-based stress reduction) was designed to address chronic pain. Participants were encouraged to explore their experience of pain, including the variety of psychological layers that were added on top of the physical sensations. It may seem counterproductive / counterintuitive, but that original study and many studies since have found that training in mindfulness meditation and attending to physical pain with mindfulness can in fact reduce the distress associated with the pain, and to some extent the pain itself.

Here are a few studies to read more:

https://pubmed.ncbi.nlm.nih.gov/7042457/

https://pubmed.ncbi.nlm.nih.gov/27658913/

This is an area of active research. It is clear that many individuals find mindfulness meditation unpleasant and can have a variety of unwanted experiences (e.g., anxiety, disturbing memories, sleep disruption). There are reports of individuals experiencing substantial impairment, particularly within the context of intensive meditation practice (e.g., long meditation retreats).

That said, evidence from randomized controlled trials as well as large-scale evaluations of common mindfulness-based interventions (e.g., mindfulness-based stress reduction) do not suggest that mindfulness-based interventions result in increased risk for serious adverse events (e.g., suicide attempt) relative to control conditions and rarely result in significant worsening of symptoms.

However, if you are exploring meditation practice and finding it challenging, I strongly suggest connecting with a qualified teacher.

Here are some scientific papers on this important topic:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0176239

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216643

https://pubmed.ncbi.nlm.nih.gov/27119968/

https://pubmed.ncbi.nlm.nih.gov/32807249/

For most of us, present moment attention is a tall order! But most scientific definitions of mindfulness also include having a nonjudgemental attitude towards our present moment experience. There are many other terms we might use to describe this attitude (curious, trusting, open, loving, kind).

The answer depends on what is meant by the term "mindfulness." In the context of mindfulness-based interventions (e.g., mindfulness-based stress reduction), mindfulness refers to a particular style of meditation practice that involves nonjudgmental attention focused on the present moment. Meditation can refer to a much broader set of practices. One might compare meditation to the category "sports," with mindfulness being just one style of practice.

That said, mindfulness has also come to refer to a dispositional tendency or trait (i.e., general tendency towards nonjudgmental, present-focused awareness) as well as a state (i.e., tendency towards nonjudgmental, present-focused awareness in a given moment). There are also interventions that encourage adoption of a mindful stance towards experience, but do not generally emphasis formal mindfulness meditation practice (e.g., Acceptance and Commitment Therapy).