We understand that you are seeking prayer for someone struggling with mental health issues. We stand with you in prayer and seek God's intervention in this situation.
Firstly, we acknowledge that true healing comes from God. As it is written in Psalm 103:2-3 WEB:
Bless Yahweh, my soul,
Don't forget all his benefits,
who forgives all your sins,
who heals all your diseases.
Remember that God is the great physician. He desires for us to be in good health. However, it is also important to know that God is more interested in our spiritual healing and salvation than just our physical healing and well-being. Regardless of what is the matter, we must first and foremost make sure that we are ready to meet Him should He decide to take us home. This can be achieved by inviting Jesus into our hearts and becoming obedient to Him. It is only by the name of Jesus that we have access to God. Furthermore, it is only by believing in Jesus Christ that we can be saved and born again. Without this, the Bible tells us that we cannot see the kingdom of God. Here is some relevant scripture on this subject:
Neither is there salvation in any other: for there is no other name under heaven, that is given among men, by which we must be saved. (Acts 4:12 WEB).
Jesus said to him, "I am the way, the truth, and the life. No one comes to the Father except through me" (John 14:6 WEB).
Jesus answered, "Most certainly I tell you, unless one is born of water and spirit, he can't enter into the Kingdom of God!" (John 3:5 WEB).
Without mentioning the name of Jesus Christ, we do not have access to God. Prayer should always be in Jesus' Name.
That being said, let us pray for this person's healing:
Dear Heavenly Father,
We come before You today, lifting up this person who is struggling with mental health issues. We ask, Lord, that You send Your peace that surpasses all understanding to calm their mind, body, and spirit. Comfort them in their struggles. Help them to focus on You, Lord, and to find their strength in You.
We pray that You guide the doctors and medical professionals treating them, giving them wisdom and discernment to provide the best care possible. We ask that You grant them the gift of faith and the gift of believing in Jesus Christ that they may be healed and their sins forgiven. If they already know You, Lord, then we ask that you strengthen their faith. We also ask that You provide them with supportive friends and family to encourage them during this time.
We believe in the name of Jesus Christ that this person can be saved and healed. We pray this in Jesus' name. Amen.
Remember that God is faithful and that His will is perfect. Trust in Him, and encourage this person to do the same. It is also wise to seek out medical help and take medications as prescribed by doctors. God works through people and medicine.
Again, encourage this person to seek Jesus Christ. We must all submit to Jesus Christ. That is the most important thing. To obtain the free gift of everlasting life, one must believe in Jesus Christ. This is the most important thing in life. It is a matter of life and death.
Then he brought them out and said, "Sirs, what must I do to be saved?"
They said, "Believe in the Lord Jesus Christ, and you will be saved, you and your household." (Acts 16:30, 31 WEB)