How long can a person be in a coma?

How long can a person be in a coma?

It depends on the cause of it. So for instance, if you go into a coma because you have renal failure, and then you get dialyzed, you may come out of it within 24 to 48 hours after that. If you have a toxic overdose--if you've taken too much of some medicine or you've made a suicide attempt--as soon as that drug is out of your system, you may wake up from it, providing that you didn't stop breathing or have a cardiac arrest from all of this. If there is permanent damage, even if it's going to be transient, it may take you weeks to come out of a coma. Head injuries, it may take you weeks to come out of a coma. Now, a lot of patients, when they go into a coma from a head injury, after several weeks they will respond to deep pain. They're just not awake, they're not talking, but they may respond to some stimulus. But how long somebody is in a coma is variable. Generally speaking, before we say that somebody is irreversible, we like to have other evidence of brain damage, not just the level of consciousness.