From an interview with Metropolitan Hierotheos of Nafpaktos:
Question: Blessed Elder Paisios of Mount Athos frequently had stated that some of the most serious problems experienced by contemporary humanity is the ever increasing spread of mental illnesses. Would it be right to think that these ailments of the soul have a spiritual background, and consequently, the only true psychotherapy for them should be the one which the Orthodox Church could provide?
Answer: Mental and spiritual illnesses, even illnesses of the body, are related to man’s existential problems, that is, his distancing from God and the entry of death to our existence. Sin is viewed as a spiritual illness. The death of the body, which we inherit from our parents and lies in our cells with the genes of aging, is a consequence of man’s distancing from God.
The Orthodox Church preserves this therapeutical method, the neptic tradition, which we may call Orthodox psychotherapy. According to St. Gregory Palamas, the Church is the Body of Christ and a communion of deification. The phrase “communion of deification” shows the way one experiences deification by Grace in his personal life.
Mental illnesses have repercussions on the body, the same way illnesses of the body affect the soul. Beyond this, there are neurological illnesses due to physical exhaustion, there are demonic influences, or sometimes God allows an illness for man’s spiritual aid. This is why in some cases illnesses of the body assist man’s spiritual life more than health does.
I believe that spiritual fathers who work on man’s therapy must distinguish between bodily, spiritual, psychological and demonic illnesses. This distinction is the objective of Orthodox theology. A theologian is Orthodox if he is able to discern between the created and the uncreated, the demonic and the divine, the psychological and the spiritual, the physical and the spiritual.
Since you mentioned Father Paisios, I have a personal view that on various illnesses he referred the ill ones sometimes to spiritual fathers, sometimes to physicians and other times to saints. He used to say often: “This kid needs a saint” and would send him to Saint Nektarios, to Saint Gerasimos, et al., while other times he would send him to physicians he knew.
Sobornost, September 2006.