There is an academic article to prove the effect of Buddhist meditation.
In Plos One, a famous academic journal collecting lots of medical research, Ido Amihai et al. in National University of Singapore reported about the effects of meditation. According to them, the influences of meditation upon your mental state are various, depending on the style of religion.
Plos One: Arousal vs. Relaxation: A Comparison of the Neurophysiological and Cognitive Correlates of Vajrayana and Theravada Meditative Practices
They examined the activity of neural network of the participants with electroencephalogram during the meditation. It revealed that some methods of meditation make you relax, whereas others make you arise. Theravada tradition was the former, and Vajrayana tradition was the latter.
It is known in general that meditation lets you being calm. So it sounds strange that Vajrayana tradition enhances your sympathetic activation. However, some mediators also insist that good meditation makes you creative. Indeed, participants using Vajrayana tradition marked better performance at a cognitive task.
So, you can choose these two methods to modify your mental state, as some mystics claim. Isn't it fantastic?
To be honest, electroencephalogram is not so precise evaluator of the brain activity. Noise and artifacts are easily inserted in it in usual situations. I hardly agree with the opinion that the pattern of electroencephalogram is strictly reflecting the deep mind of a person. Some more complex techniques such as functional MRI or PET are required to examine the exact influence of meditation upon our brain activity.
Nonetheless, there has been lots of studies to visualize the effect of some spiritual activities with newly technology. It is an interesting tendency.