Jesus Christ, the Good Shepherd Who lays down His life for the Sheep (source)
Note: It seems that as the years progress, we are seeing more and more people afflicted with Depression, Anxiety, Bipolar disorder, Schizhophrenia, Suicides, and many other mental illnesses. Though the church fathers would not question that genetics, history of abuse, etc. and other things that one cannot control can affect one's mental health, it is clear that our society doubts the role that the passions, sins, demonic influence and temptations, and overall separation from Christ play in affecting our minds. Thus, while it may be help to seek treatment with therapists or psychiatrists, it is truly necessary that we open our hearts towards our Merciful Christ in repentance, for He is our Creator, Who ever loves us and gave Himself up for us all. He is the Good Shepherd, Who seeks us out, the lost sheep, and places us on His shoulders, and brings us to the Father.
Also see pages on Saints Gerasimos, Dymphna, Issac the Syrian and Ephraim of Nea Makri, whose intercessions or writings have been known to help people with mental illness.
Orthodox Prayers for Deliverance from Depression, and Various Psychological Afflictions
(by Fr. Sabbas the Athonite)
O Greatly-merciful Master, Lord Jesus Christ, the Physician of our souls and bodies, come and heal me, Your worthless servant. I have distanced myself from You, I have wounded Your Goodness and Love. I have sinned against Heaven and before You. I have worked all iniquity. I am utterly bed-bound, barren of every virtue and bodily or spiritual healthy. My body is sickened. My soul is afflicted. My spirit is weakened. My will has been overrun. Everything within me is drowned and suffers. I have descended to "the lowest Hades". Deliver me, O Lord, from the spiritual choking and the mourning in the depth of my heart, and the depression which rightly tortures me. I have worked all sins. These war against me. These have placed upon me this unbearable torture. Have mercy on me, O Lord. I, alone, am responsible for this desertment and destruction of my soul and body. Egotism has ruled over me. Negligence has enslaved me. Laziness has deadened me. Forgive me, O Lord, and heal my wretched soul. Drive far from me the evil spirit which works within me and which brings to me this unbearable choking of soul and body. Drive far from me the weight of depression from my heart. Free my soul and body from every negligence, laziness, high-mindedness, bloating, depression, faithlessness, indifference, unconsciousness, despair and deadening. I, myself, have brought all these things upon my soul. Forgive, O Lord, the multitude of my sins. Heal me from the multitudes of my passions. Grant, O Lord, that I might not suffer anymore on behalf of the passions which rule my wretched soul. Take up the heavy burden of my sin. Drive away from me every enemy and battle. Grant peace, O Lord to my life and my soul. Cleanse me from every corruption of flesh and spirit, that I might be able to flee from the evil spirits which worked this darkness and cloudiness within me, along with desperation and hell. Lift me up from my bed of pain, and pallet of evil. The depression and the fear and the slavery of my thoughts, drive away from me. Lord, let Your will be done as You desire. With Your Graciousness and Goodness, trample down my enemies and the old man, together with its passions and desires. Lord, let Your will be done within me, that I might rejoice and exalt, without sorrow, and with joy follow You and glorify You, hymning and blessing You unto all the ages. Visit and strengthen me through Your Providential Power, that I might glorify and chant unto You, the Compassionate Lord, together with the Father and the Spirit unto the ages. You, my Comforting [Jesus], together with the Great and Surpassingly-Compassionate Father and the All-Comforting Spirit, come and find me, among all the trials all the days of my life. Have mercy on me, O Lord, and forgive my saddened and distressed soul and body. You are the Joy and the Light, the Resurrection and the Life, the Spring and our Joyous Pascha. For You told us: "Him who comes to me, I will by no means cast out". You are He Who descended to the "storehouses of Hades", to seek the lost sheep, that is me. Have mercy on me, through the intercessions of Your All-spotless Mother, the All Surpassing Joy of All. through the power of Your Precious and Life-giving Cross, the Tree of Life, through the intercessions of the Precious Heavenly Bodiless Powers, through the intercessions of the Holy Archangels Michael and Gabriel, through the intercessions of Your Holy glorious and all-praised Apostles, the Holy glorious and victorious Martyrs, our Venerable and God-bearing Fathers, and all Your Saints. Amen.
O Greatly-merciful Master, Lord Jesus Christ, have mercy on me and cleanse me from every sadness and disturbance and cowardice. Drive away from me every spiritual choking and demonic sorrow, that I sense in my body and my soul. For You are our Joy, and the Jope of all the ends of the earth, adn those far off at sea. Be merciful to me, O Master, upon my sins. Take from me the heavy burden of sin and despair. Drive far away from me every sadness and laziness. Confirm me in Your Love, and with unassailable hope and unshakable faith in You, through the intercessions of Your Spotless Mother, and all Your Saints. Amen.
From the book: The Passions and Depression---What are they, and how are they healed?, by Hieromonk Sabbas the Athonite. Amateur translation of text from here.
Another prayer for Mental Health
O Master, Lord my God, in Whose hands is my destiny: Help me according to Thy mercy, and leave me not to perish in my transgressions, nor allow me to follow them who place desires of the flesh over those of the spirit. I am Thy creation; disdain not the work of Thy hands. Turn not away; be compassionate and humiliate me not, neither scorn me, O Lord, as I am weak. I have fled unto Thee as my Protector and God. Heal my soul, for I have sinned against Thee. Save me for Thy mercy's sake, for I have cleaved unto Thee from my youth; let me who seeks Thee not be put to shame by being rejected by Thee for mine unclean actions, unseemly thoughts, and unprofitable remembrances. Drive away from me every filthy thing and excess of evil. For Thou alone art holy, alone mighty, and alone immortal, in all things having unexcelled might, which, through Thee, is given to all that strive against the devil and the might of his armies. For unto Thee is due all glory, honor and worship: To the Father, and to the Son, and to the Holy Spirit, now and ever, and unto ages of ages. Amen
Through the prayers of our Holy Fathers, Lord Jesus Christ our God, have mercy on us and save us! Amen!