Ved Kovid, Durgadas talks about meditation and explains how various 'effects' of meditation perceived today are actually seen as psychological not spiritual states in traditional Yoga and Ayurvedic psychology.

 Spirituality and Meditation (Dhyana)

By Ved Kovid, Durgadas.

(c) Ved Kovid, Durgadas / Arogya Ayurvedic Health Ltd.
All Rights Reserved. 

Meditation has become almost a special "science" and "technique" in itself today, but few realise what actual benefits they are having. Many talk about states of consciousness. Well, to attain them takes lifetimes of intense study, austerities and practice as also development of sattvas or purity. Now for most in Kali-Yuga, even advanced Gurus and sadhaks (spiritual aspirants), this is very difficult. First one also requires strong iccha-shakti (will-power) and dharana-shakti (power of concentrated thought) for proper meditation to occur as a flow of continuous consciousness freed from the lesser shackles of the mind and again, even few trained Yogis and Gurus can really enter this state on a deeper level, although many aspire to, wish to and teach others in incomplete manners to.

Yoga and Ayurveda also understand several spheres or levels of mudha (delusional) and also vikshepa (projectory or hallucinating) mind and hence also placebo effects, visions and states of "calmness" temporal and produced by vasanas or mental impressions also. These can also be due to (a) malas (wastes) in the mental channels creating disturbances and false visions due to diet, lifestyle etc. (as in dreams) and (b) due to nefarious astral beings assuming forms of Devas (divinities), Rishis (seers) and other or possession by lower astral entities invading one's prana or life-force / psychic being.

Yet everyone today forgets this and thinks their meditations and meditational experiences are "spiritual". But this is nothing more than a cultural and self-righteous egoic trait in society left by Christianity and the western Eurocentric mindset. It fails to understand the depth of Yoga and Ayurvedic psychology that not only encompasses, but expands upon and transcends the views of modern psychology and psychological states. What is more, the teachers, techniques and environments for meditation today are very, very superficial and hence only surface-level effects as explained above will manifest, not the deeper true levels of Consciousness.

These mudha-bhavas or delusional states of the mind can even extend to lower-astral experiences where one falsely beholds themselves as "being one with consciousness", as the physical human plane is so dense in this current age, that anything, even indigestion or light-headedness in extremes can make one feel one is "one with consciousness", which also includes examples as OBEs, which to the limited, untrained human complex, can be a feeling confused with "enlightenment", as few reach the higher stages beyond this, except for very advanced Yogis (who are usually born from the astral and causal planes in human form for specific missions).

Some meditations are also correctional for the mind and simply instill a state of santosha or contentment and shanta or calmness in individuals, not simply due to the effects of meditation per se, but the direct effects of opposite cures (as a Kapha or heavy and lethargic mind does well with Vata (wind)-increasing formless meditations and fiery ones, or Vata (wind or hyperactive minds) does well with warming and watery or dense or emotional ones, such as on deities). These are biological not simply psychological in nature and should be noted as such. Spiritual effects are rare, very rare and always have been.

We should also realise that Buddhist Meditations such as mindful meditations are also not the goal of meditation as per Hinduism, which requires a state of the purified mind which is nirodha or with cessation of all thoughts and even of the mind itself, dwelling in the state of the Atman. Not all philosophies are the same, hence why the great monist, Adi Shankaracharya (c.500BCE) refuted Buddhism and within the older Vedic system, Buddhists are seen as dwelling not in the sphere of the non-Self (or in Hindu terms, the attributeless state of Nirguna Brahman where the Self merges into the Supreme and the "identity" of the jiva or individual soul is nullified), but lost in the buddhi or intellect itself, in the rajasic state of excess debate and logic, from which they may gain mastery over the physical world and sciences, but not of the inner Atmic or Self-worlds and sphere. 

This is a clear example of how even Indian gurus have presented a very limited, incomplete and westernised image of such things Vedic into the West by not properly understanding it themselves first.