This fascinating Illinois State Bar Ethics Opinion 17-01 presents this question under the state's RPC 1.6(c)which mandates disclosure "to the extent the lawyer reasonably believes necessary to prevent death or substantial bodily harm". :
The inquiring attorney has a client who is addicted to heroin and opioids, and also takes cocaine, marijuana and methadone. The client is arrested for possession of a controlled substance, and appears severely impaired during court hearings, but remains silent before the Judge, allowing the attorney to do the speaking. The client is unable to stop consuming heroin and continues to be in violation of bond conditions.In essence the bar committee finds insufficient immediacy of harm but suggests that in appropriate circumstances RPC 1.14 Diminished Capacity may allow the lawyer the ability to take protective steps.
Required to Report a Client’s Drug Addiction? Illinois Says Not Necessarily… | Legal Ethics in Motion
by Nicole Comparato
A recent Illinois ethics opinion advised that although a lawyer is obligated to reveal confidential information about a client if is deemed reasonably necessary to prevent certain death or substantial bodily harm, a client’s addiction to heroin or opioid drugs will not trigger that obligation, absent more specific factual details that indicate the risk is not simply remote and uncertain.
This opinion responded to an attorney’s inquiry about a client, who appeared severely impaired during court hearings and had been unable to stop consuming heroin in violation of bond conditions. Illinois Rule 1.6 departs from ABA Model Rule 1.6 and requires mandatory reporting of life-threatening, dangerous information (rather than discretionary reporting).
The opinion acknowledged that this kind of drug addiction is serious and poses a danger to the client’s safety and wellbeing, but could not conclude that the mere knowledge of such an addiction triggers the mandatory obligation. Though the risk need not be immediate, Comment  to Illinois Rule 1.6 states that there must at least be a present and substantial threat that the person will suffer such harm at a later date if the lawyer takes no action to eliminate the threat.
Here, the opinion states that even though this client’s drug addiction presents a future risk, “such danger is sufficiently remote in time and uncertain of occurrence as to render us unable to say that it presents the present and foreseeable threat … as would be required to call the Rule into play.” Therefore, under the circumstances, disclosure was not required.
The opinion made clear that this analysis is “intensely fact-sensitive” and that there could be a factual scenario where a drug addiction requires mandatory reporting—such as a client with a history of attempted suicide or self-inflicted bodily harm. Furthermore, the opinion offered an alternative to Rule 1.6, suggesting that Rule 1.14, which discusses clients with diminished capacity, allows for an attorney to take protective actions such as consulting with necessary entities or appointing a guardian, if necessary, without violating confidentiality. These are all avenues that an attorney should consider if confronted with a similar situation.