What is the ruling on succumbing to the disease of depression, which causes severe lethargy, a wish for death, and an inability to maintain one's health and leave bed?

Wishing for death due to hardship is prohibited, as the Prophet (peace and blessings be upon him) said: "None of you should wish for death because of a hardship that has befallen him. If he must wish, let him say: 'O Allah, keep me alive as long as life is better for me, and cause me to die if death is better for me.'"

The sick person should strive to repel the affliction by seeking treatment, consulting trustworthy doctors, increasing in the remembrance of Allah, seeking His help, and supplicating, all while maintaining a strong will and a good opinion of Allah Almighty.