I think our faith tells us to rely on on faith and supernatural outlook and what Jesus teaches than what psychology and medicine teaches; although these have to be taken into account, God’s will prevails.
Jesus said: Take this cup from me (take away discomfort, displeasure, unhealthy bloodletting, psychological and physical torture of scourging and crucifixion), but not my will but yours be done. He talked about the “necessity of suffering” and called Peter “Satan” when the latter tried to stop him.
For your information, there is an entire article on Mortification of the Flesh in Wikipedia which discusses the History of this practice and the Modern Theology behind it, including what the Popes have said. See
en.wikipedia.org/wiki/Mortification_of_the_flesh
Some quotes:
In the second millennium, Saint Francis of Assisi, who is known to have received the stigmata, painful wounds like those of Jesus Christ, is said to have asked pardon to his body, whom he called Brother ***, for the severe self-afflicted penances he has done: vigils, fasts, frequent flagellations and the use of a hairshirt.
At the latter half of the 20th century, Saint Josemaría Escrivá practiced self-flagellation and used the cilice, a modern-day version of the hairshirt. Saint Pio of Pietrelcina, a modern-day saint who received the stigmata wrote in one of his letters: “Let us now consider what we must do to ensure that the Holy Spirit may dwell in our souls. It can all be summed up in mortification of the flesh with its vices and concupiscences, and in guarding against a selfish spirit… The mortification must be constant and steady, not intermittent, and it must last for one’s whole life. Moreover, the perfect Christian must not be satisfied with a kind of mortification which merely appears to be severe. He must make sure that it hurts.” Like St. Josemaria, Padre Pio and Mother Teresa of Calcutta used the cilice and discipline regularly as means of doing penance.
From John Paul II: Faith in sharing in the suffering of Christ brings with it the interior certainty that the suffering person “completes what is lacking in Christ’s afflictions”; the certainty that in the spiritual dimension of the work of Redemption he is serving, like Christ, the salvation of his brothers and sisters.
It is suffering, more than anything else, which clears the way for the grace which transforms human souls. Suffering, more than anything else, makes present in the history of humanity the powers of the Redemption.
From the Catechism: 1430 interior conversion urges expression in visible signs, gestures and works of penance.