Depression or anxiety disorder does not automatically disqualify a person from entering Religious life. Discernment is taken on a case to case basis. Depression comes in different levels and some authorities on this will agree that some form of depression can be an appropriate response to a given event. “Circumstantial depression” is a form of behavior response appropriate to some given circumstances of death, grave loss of loved one, home, wealth, job, etc. It usually is passing and temporary. I am not a professional psychologist but my nursing experience has exposed me to this knowledge.
Religious life a particular form of lifestyle not suited to everyone. A desire to be a Priest, Sister/Nun, however great it may be, does not guarantee a definite calling to this life. But Chronic depression and Chronic Anxiety disorders are conditions that are very hard to reconcile with Religious life. It is not to say that those in religious life now are “superhuman, perfect” people who are free of anxieties and are always happy. That is not always the case. But the stresses of community life, ministerial demands, spiritual challenges are constant factors one faces. In the past, little consideration was given to the psychological state of candidates and communities suffered and continues to feel the effects of this neglect years later. Some entered with this condition, only to leave later because the life and stress became too much for what they can take. The Church is wise to require that a candidate be psychologically balanced.
I do not believe that decline in religious vocations is caused by the lack of mentally sound people! And even if it is as Vickinator16 indicated, we are not just looking to inflate the numbers but are looking for vocations that persevere. No, lack of vocations is created by a number of factors.
I would like to offer encouragement to those who find themselves with this problem and feel a great desire for Religious life. Religious life is a call from God. We do not create it nor do we make it happen. God does the calling and we only respond. Discerning whether a person is fit for Religious life is given to the Church by the Holy Spirit who discerns all truths. We have to accept this in faith. We have to accept this in humility. If you find that you do not have the necessary qualities, that does not make you a lesser person! Entering religious life is not necessary for salvation. Loving God and being obedient to the Commandments are. It is better to be out of a convent and doing God’s will than to be in a convent following one’s own will!