What is the ruling on someone with obsessive-compulsive disorder (OCD) if they commit suicide?

Suicide is one of the gravest major sins, as Allah Almighty says: "And do not kill yourselves. Indeed, Allah is ever Merciful to you." The one who commits it does not leave the fold of Islam, and funeral prayers should be offered for him. However, it is preferable for prominent scholars to avoid leading the funeral prayer, as the Prophet, peace and blessings be upon him, did with a person who killed himself.