Faith insofar as it is a virtue, is a perfection of the intellect. Therefore, contrary to modern psychological opinion is not, in itself, harmful to one’s psychological health. Every mental illness is in some way contrary to the virtue of faith in its object (revelation).
Faith looks at God and creation under the ration Dei, i.e. faith helps one to see the created order as it is properly related to God, its creator. Hence faith helps us to understand certain things about creation which cannot be known through the natural light of reason, e.g. we know that God has explicit plans as part of His providential care for us and human beings. Therefore, certain phobias actually deny that God is taking care of the person who suffers the phobia. For instance:
- If one has a fear of the future, the tacit premise is that God will not take care of his needs in the future.
- Another example would the case of the person who suffers from a desire to control excessively certain things in his life. This fixation denies that God ultimately the author of history and so, try a we might, it is ultimately up to God determine how and to what extent we will have control over anything.
Another aspect has to do with self-detachment. Now since faith tells us that the whole created order was created for God’s glory, then we learn that creation is really about God and not us. Many fixations implicitly deny that reality is about God, e.g. the man who has a fixation on sex views the woman as something to satisfy himself rather than something created for God’s glory. Also, every phobia stems from
a) a lack of confidence in God to protect and take care of someone, i.e. it is a denial of providence;
b) it is a manifestation of lack of detachment as one is overly concerned about one’s well-being;
c) it is a lack of spirit of mortification as it exhibits a lack of willingness to suffer some future evil.
The object of faith also helps us to correct our judgment about ourselves. Through the teachings of the faith we learn our proper relationship to God, family, friends and even enemies. Since relations can be prime material for mental health or illness issues, a proper faith helps our judgments of others to be rightly ordered.
As our judgments are rightly ordered, this will redound to the imagination and the cogitative power, which will make associations in different ways than they would merely by natural habit. The images can be stored in memory so that in times of suffering or trial the person has something beneficial to occupy his imagination. He can see his suffering as ordered to something greater and can imagine or reflect upon it. All of the effects on the imagination and cogitative power will have an effect on the appetitive life as well. Since that which is higher redounds to that which is lower, no area of man’s ontological make-up which relates to mental health is unaffected.
Revelation provides a moral code by which a person can lead a life according to right reason and the natural law and, as a result, if we do what God tells us in revelation since He knows how we are designed, since He designed us, we cannot but expect to achieve and preserve mental health by following His precepts and commandments. Moreover, since faith orders us toward the object of perfect beatitude (God), faith is the beginning of eternal beatitude and so we can actually begin the process of striving for happiness through faith.
While faith itself is a perfection and those who act in accordance with that virtue can never adversely affect their mental health, it is possible that a man who has faith can actually act in ways not suited to that virtue and therefore adversely affect his mental health. At Times, people will give assent to things which are actually contrary to the faith or not part of faith, which can lead to mental illness,. This is why a clear knowledge of the faith is necessary on the side of the psychologist so that he can properly instruct the directee in the area of the faith which he does not properly understand. Moreover, since he teaching of faith command us to perform certain actions, if a directee does not understand the action to be performed, i.e. he does not know what to do or how to do it according to due circumstances, it can have an adverse effect.
One could go on but the point is that when one looks at any created thing, about which any mental illness can be had, it can be seen that the thing is not looked at from the point of view of God or the faith.
Faith helps us to correct our judgment. It corrects our judgment because it helps us to judge the world the way God sees it. Moreover, the images associated with various articles of faith provide an avenue of correction of the cogitative power, e.g. reading various descriptions of hell by the saints provides the cogitative power with the images which will actually aid one in detaching oneself from something to which one might have a fixation. The images of heaven provide the cogitative power with positive images which can aid one in overcoming sorrow.
In effect, the various images associated with the doctrines of faith provide and avenue by which, if one meditates on the images, the various faculties are rightly ordered. For example, statues of the Holy Family helps us to recognize the right order within families, how the various virtues are necessary to live rightly within a family, such as justice, charity, self-denial by seeking the good of others over the good of self, etc. The doctrine of the saints provides ample example of heroic Christian virtue which can incite one to develop the proper virtues and thereby ward off any possible mental illness in those areas.
 Ripperger, Chad, FSSP, Introduction to the science of mental health, (Sensus Traditionis Press: Denton, NE,) 2007, p. 365-366.