“Addiction” and “substance use disorder” are both acceptable and may depend on the context — the former is more recognizable to a nonmedical audience, for example.
“Addict,” “alcoholic,” “abuser” and other terms that define a person solely by their addiction should be avoided. Use person-first terms such as “people with a heroin addiction” instead.
“Died by suicide” or “killed themselves” is preferable to “committed suicide,” as “committed” can imply that the person did something illegal.
Relatedly, do not describe suicide attempts as “successful,” “unsuccessful” or “failed,” which are value judgments rather than neutral descriptions of a situation.
Avoid terms such as “mentally ill,” which can insinuate that someone’s mental illness makes up the entirety of their mental state or that because they have a mental illness they are not “mentally healthy.” A person can have a mental illness such as depression and still be mentally healthy. Instead, specify the illness or use a phrase like “living with mental illness.”