How Continued Drug Use Leads to an Overdose

Filed under Addiction

How Continued Drug Use Leads to an Overdose

Tolerance forms after people abuse drugs frequently, but it proves to be a false net of security when it unexpectedly fails and leads to fatal overdose

During the past decade, death by accidental drug overdose has grown exponentially. Most of these overdoses result from prescription drug and heroin abuse, and many people turn to the latter drug once their prescription opioids become impractical to obtain1. Most people understand overdose to involve someone who abuses a drug, gradually increases the dose and eventually takes so much that she overwhelms her body to the point of death. In other words, there is no standard amount that causes overdose for everyone: each person has different health factors, experiences and metabolic rates, and even these factors change over time, so you could risk overdose with the same amount of drugs that you consumed yesterday. In other words, you could take a large dose of a drug and overdose the next time without any warning2.

Tolerance is a key factor in overdose. Through continued drug abuse, the body comes to withstand the substance without experiencing the same effects. Unfortunately, as tolerance builds, addicts increase the dosage to get the same effect, which means they may end up taking too much at some point in this cycle. Generally, opiate overdose depresses the respiratory systems, which can cause death. Frequent drug users typically have greater resistance for respiratory depression than novice drug users, but overdose can occur when someone finally surpasses his tolerance and shuts down his ability to breathe.

Classical Training in Behavioral Tolerance

Some researchers believe that learning affects the way an addict develops her tolerance3. Sometimes termed “behavioral tolerance,” people train themselves to behave a certain way as they reinforce their behavior either positively or negatively, so substance abuse is not the only factor when it comes to tolerance. Psychological connections significantly affect the way a drug influences her, and these connections vary between environments, location and context. Simply stated, someone may take the same amount of drug and get even higher than the day before simply depending upon where she is.

For example, imagine that someone frequently slips prescription pills from his grandmother’s medicine cabinet. Each time he goes for the medicine, his body triggers tolerance adapters to prepare him for the drug he will soon abuse. Now, that same person may grab that same pill out of context, perhaps spontaneously if he finds a leftover in a coat pocket. The body may not notice the cue that the drug is coming, but may fail to prepare its tolerance because the situation is different. Thus, even though he ingests the usual amount, an overdose can ensue, because his body is unprepared. Tests on this thinking confirm that changing the context in which a drug is administered can change its effects on the body.

The Danger of Addictive Reasoning

Most drug addicts are unaware of this aforementioned concept. They may believe that they are safe taking the same amount of the same drug ought every day. After all, if tolerance forms over time, then it should be fine to take a little more with every use. However, as explained above, psychological alterations cause the physical experience of drugs to differ each time, and tolerance levels may change drastically from one day to the next4. An amount that failed to cause a high one day can be more than enough tomorrow to be lethal.

Continued drug abuse and tolerance build a false and dangerous sense of security. Even though negative consequences occur from addiction throughout life, addictive habits continue, so the addict has no control over her decisions and reasoning power. At this point, it is important to get professional help, as addicts program themselves more and more to abuse drugs the longer addiction continues.

Other Causes of Overdose

The more people engage activities, the more heavily those activities influence them, so the chances of overdose rise with each and every bout of drug abuse. Furthermore, combining drugs increases the risk of overdose. Prescription drug addicts who frequently take even moderate amounts of medications can experience greater complications if they ingest over-the-counter substances with their drugs of choice. Lastly, metabolism and resistance abilities change over time with age and factors related to health and genetics. As a result, addictions that last for quite some time may lose bodily functions that support drug abuse, which means a fatal overdose may occur unexpectedly. In short, quit abusing drugs as soon as possible to protect your long-term health.

Get Help for Drug Abuse

With drug abuse being as common as it is, make careful choices when you take medications. If you abuse prescriptions, then please contact us for help managing them and to learn what safe prescription habits entail. Even one addiction can affect the lives of many people, so call our toll-free, 24 hour helpline now for instant support. Our admissions coordinators will help you, answer your questions and connect you with professional treatment, so reach out for help now to begin recovery as soon as possible.


1 Ohio Department of Mental Health and Addiction Services. “Increasing Heroin Overdose in Ohio: Understanding the Issue.” Retrieved 1/12/16.

2 Journal of Forensic Sciences. “Some observations concerning blood morphine concentrations in narcotic addicts.” By Monforte, J. R. Published in 1977. Retrieved 1/12/16.

3 Journal of comparative and physiological psychology. “Evidence from rats that morphine tolerance is a learned response.” Retrieved 1/12/16.

4 Department of Psychology McMaster University, Hamilton Ontario. “Pavlovian Conditioning and Drug Overdose: When Tolerance Fails.” Published in 2001. Retrieved 1/12/16.

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