Drug overdoses are frequently accidental, but not always. Investigating police, emergency technicians, healthcare providers, and even forensic pathologists (if the overdose results in death) generally play a role in helping to determine if the overdose was accidental, suicidal, or even an attempt by another to do harm. Drug misuse is often the reason for accidental overdoses. Unintentional drug overdose can result for many different reasons, which we’ll explore here. There is a connection, however, between alcohol and drug overdose deaths related to dual diagnosis and mental health disorders. As many as a third of people with substance use disorders also have a dual diagnosis, which can leave them more at increased risk of suicidal thoughts and attempts.