Dear Mike:

There is no such thing as a psychic, medium, or the like getting "powers" from God. Also, most of these people are frauds using well-known techniques to pretend and to con their audience/customer that have some real power. For those who actually do tap into some "power", that power is from the devil. They can use all the trappings of Christian icons, prayers, and rituals they wish to hide the fact that what they are doing is devilish and is absolutely and categorically condemned by God. There are no exceptions.

Deuteronomy 18:10-12 is crystal clear on this:

There shall not be found among you any one who burns his son or his daughter as an offering, any one who practices divination, a soothsayer, or an augur, or a sorcerer, or a charmer, or a medium, or a wizard, or a necromancer. For whoever does these things is an abomination to the LORD; and because of these abominable practices the LORD your God is driving them out before you. 

It is not just a sin, but it is an "abomination to the Lord." There are not many sins that are classified as an abomination, but this is one of them.

In addition, practicing these abominations, or going to people who do, is a violation of the First Commandment. There is no sin worse than that against the First Commandment to have no other gods before the one true God.

In the Catechism of the Catholic Church, in the section on the First Commandment, we find this warning:

Divination and magic

2115 God can reveal the future to his prophets or to other saints. Still, a sound Christian attitude consists in putting oneself confidently into the hands of Providence for whatever concerns the future, and giving up all unhealthy curiosity about it. Improvidence, however, can constitute a lack of responsibility.

2116 All forms of divination are to be rejected: recourse to Satan or demons, conjuring up the dead or other practices falsely supposed to "unveil" the future.48 Consulting horoscopes, astrology, palm reading, interpretation of omens and lots, the phenomena of clairvoyance, and recourse to mediums all conceal a desire for power over time, history, and, in the last analysis, other human beings, as well as a wish to conciliate hidden powers. They contradict the honor, respect, and loving fear that we owe to God alone.

2117 All practices of magic or sorcery, by which one attempts to tame occult powers, so as to place them at one's service and have a supernatural power over others - even if this were for the sake of restoring their health - are gravely contrary to the virtue of religion. These practices are even more to be condemned when accompanied by the intention of harming someone, or when they have recourse to the intervention of demons. Wearing charms is also reprehensible. Spiritism often implies divination or magical practices; the Church for her part warns the faithful against it. Recourse to so-called traditional cures does not justify either the invocation of evil powers or the exploitation of another's credulity.

2138 Superstition is a departure from the worship that we give to the true God. It is manifested in idolatry, as well as in various forms of divination and magic.

Nothing can be more clear. There are no exceptions.

Anyone who has practiced these "arts" or who has consulted these people needs to confess it and also to renounce the sin by taking back ground that Satan has taken in his life by consulting or practicing these abominations.

I recommend our Prayer After Confession to Re-Claim Ground Taken by Satan.

Finally, those who practice these "arts" and those who consult with them not only commit a sin, but they also risk possible demonization. This is not a trivial matter.

God Bless,
Bro. Ignatius Mary