Afterlife after OD

I'm interested in hearing from individuals who are not followers of Abrahamic faiths (no disrespect intended). What do you think happens to a person when they die from a drug overdose? I wonder if they have difficulty accepting their death? Also is there anything mourners do that keep them from moving on in the afterlife instead of clinging to their earthly life? I've heard mixed things, such as it's important to wait at least 90 days before attempting to contact them or that excessive mourning can hold them back.