There are people who argue that it is fine to commit suicide for a good reason. However, their arguments are flawed.
Suicide is unlawful for any reason.

“And do not kill yourselves. Indeed, Allah is to you ever Merciful.”
Quran 4:29

The body has no choice but to pass through the gate of physical death. This death is a must for human beings and there is no escape from it. Never seek it, for it will seek you.

“Every soul will taste death. And We test you with evil and with good as trial; and to Us you will be returned.”
Quran 21:35

However, there is another type of death which is by choice and honourable. And that is to let all the inner desires of the self in pursuing that which is unhealthy die a death.
For how long will you keep drinking alcohol, fornicating, taking that which is not yours?… Let it die a death. And live a true life.
Have you not read?

“Death is noble.
Forfeiting is heart-breaking and sorrowful.
Death is dissociation from the creation.
Forfeiting is dissociation from the Creator.”
Sidi Abu Madyan [Born 509 Hijra / 1115 and died 594 Hijra / 1198]