LSD and things like that offer something that is mindblowing and altering in a very obvious way. The gifts of the spirit in the Orthodox life (and I going by what I've read and experienced) are often very subtle -- being able to repent faster after sin, being able to cut off from sins which once happened frequently and spontaneously, naturally returning to a prayerful state, naturally being able to love others, getting insights into the spiritual life, peace, wanting to help others more, things like that. They are subtle, yet profound. Sometimes, we don't even notice them when they happen, but only upon reflection ("It used to take me hours or days to repent after sin, now it happens in minutes"). Unlike psychedelics, drugs, or other forms of "experiences" that are rooted in the passions, sin, and deception, these gifts are rooted in God's Truth and Grace.