Layne Redmond on the shamanistic and meditative affect of drumming on the brain.
For some people -- whether "naturally" alert, tweaking on coffee, hyper-vigilant due to childhood trauma and finding "mindfulness" meditation practiced as "wakefulness" really easy, chasing a racing mind -- just being in the present moment is not easy.
Distinguish this with most people who are actually in a natural state, easily able to slip into light hypnotic states, deep relaxation, normal concentration, and easily in the now. When one realizes that others can come into the present -- can be relaxed, can focus (which means actively tune out the extraneous by not attending to it), can abandon discursive thought (evaluation, judgment, measurement, assessment, liking, disliking, and confusion) -- one may get anxious and wish for a way to let go and relax into a calm and cool collected state.
The best help is good health, a natural-nonsynthetic diet, avoiding stimulants, getting lots of sleep and even more sitting practice. Yet if one is physically healthy and mentally unstressed and is still unable to let go and let things be, more is needed: binaural beats; supplements (B-vitamins, magnesium, GABA, multiples); herbs (St. John's Wort, Skullcap, Hops, Kava, and so on; tryptophan, melatonin, tyrosine... But when all else fails, there's tradition. There's the drum. There's the beat to establish entrainment.