Most cases of drug overdose that are not fatal are considered accidental overdoses unless the person was attempting suicide. When a person dies from an overdose the medical examiner will need to determine whether the overdose was intentional or unintentional. If a person’s overdose is determined to be intentional then it can be assumed the individual was committing suicide.
An accidental overdose can come in many different forms depending on the type of drug the person used and their intention in taking it. In many cases if the person is an addict they may have taken more than their own tolerance could handle and end up overdosing. This happens frequently when users attempt to quit for a period of time and then start using the amount that they used to without realizing that they have lost their tolerance.
In other cases of overdose the person may have taken the drug accidentally because it was laced with something else or they mistakenly thought it was another substance. This is also a case where the person does not have a tolerance for the drug and their system cannot handle it. A less common occurrence but equally dangerous situation is when another person gives them a dangerous drug either intentionally or unintentionally and they are poisoned.
The only incidence where an overdose is not considered accidental is when a person purposefully takes too much of a drug because they intend to end their own life or otherwise harm themselves. Being aware of the dangers of a particular drug, always knowing what you are taking and evaluating your own tolerance can help prevent accidental overdose.