A couple of years ago I was told by a young man that when he prayed after smoking weed his experience was vivid and amazing he felt spiritual, joyous and really connected to God. He asked me what my view on his experience was.
The two sons of Aaron the High Priest on the day of the dedication of the Sanctuary in the wilderness were killed by Divine fire entering through their nostrils. The Biblical reason given was that they had brought strange fire that God had not commanded (Leviticus 10:1).
In the Midrash, in contrast, the sons of Aharon are accused of ministering in the holy precincts while in a state of drunkenness :
Said Rabbi Yishma'el: the two sons of Aaron died only because they entered the Tent of Meeting while drunk. In the text following their death, God commands Aaron and says: "You must not drink wine nor strong drink, neither you nor your sons, when you enter the Tent of Meeting lest you die, it is an eternal statute forever..." (10:8-9). We therefore may infer that they died only on account of wine (Midrash Vayikra Rabba 12:1, 5).
Rabbi Yishma'el connected their indiscretion with intoxication, for although strong drink is often a source of emotional or spiritual inspiration and happiness (Psalms 104:15), it can also cloud one's judgment, removing inhibitions and cause a person to ignore the boundaries between awe and love of God.
God wants us to bond with him in our normal state, one should not seek to enhance a spiritual experience by artificial means.