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Drug Tolerance Definition Psychology

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The phenomenon of tolerance emerges as one of the chief characteristics in the physiological and psychological make-up of every abuser, addict, or chemically dependent person. But what is the drug tolerance definition? Tolerance, simply put, refers to the process by which the body acclimates to the presence of an abused drug. Occurring simultaneously with tolerance is another physical phenomenon, Dependence. Dependence emerges alongside tolerance and is the process by which body requires increasingly larger doses to experience the same results one initially experienced before tolerance set in. In this regard, the two phenomena are not only bound to one another but predictable hallmarks of addictive pathology. They emerge in virtually every scenario where prolonged abuse exists. So why is knowing the drug tolerance definition important?


Drug tolerance definition psychologyIt should be pointed out that the term tolerance is frequently employed improperly and thus generates as much confusion as it does clarity. Many don’t know the true drug tolerance definition. A common example of the misapplication of the term tolerance would be to refer to a person’s ability to consume large amounts of a drug and while maintaining an appearance of normality or a semblance of functionality. It is ironic that with regards to this example, it is in some respects not entirely incorrect, but these definitions lack the clinical context that makes the term significant with regards to habituated abuse. Tolerance cuts across drug types without regard for what substance the person is abusing; e.g., tolerance can develop from abusing opiates as well as stimulants like Methamphetamine.


Significantly, one of the most striking features of tolerance is its consistent presence in all cycle three variations of Abuse. For reasons of treatment protocol it is worth noting that tolerance also develops regardless of whether or not the drug was obtained legally (through a doctor) or purchased illegally (on the street). In other words, the body does not distinguish between opiates legally prescribed to manage post-surgical pain, any more than it distinguishes the effects of ingesting street narcotics such as heroin.


Before going any further it is necessary to enlarge upon the term and define precisely what tolerance means. For clarity’s sake, what we mean when we refer to tolerance is a physical and psychological appetite that develops and eventually emerges as its own distinct illness, complete with predictable symptomology and a fairly common set of stages through which the addict passes. Following prolonged use of certain medications, Tolerance occurs along the entire spectrum of abuse, because it occurs in the wake of prolonged consumption of some medication, be it sedative, Stimulant, and painkiller.

Multiple Routes of Development

As stated previously, tolerance can manifest via several routes; which means it can develop regardless of whether the person is injecting, snorting, or smoking their drugs. Complicating matters is the fact that physiological tolerance, which invariably develops in tandem with psychological dependence, frequently manifests as secondary mental health disorders such as Depression, Anxiety, or some form of Mood Disorder (a complete list of co-occurring disorders is outside of the scope of the particular article. Suffice to say where addiction occurs it is not uncommon to find the presence of other mental health conditions. When a doctor diagnosis a person with one or more co-occurring illnesses they have a dual diagnosis – more below).

By the time tolerance has developed, the addict has likely experienced the symptoms of other disorders; which essentially means that the person’s psychology is now compromised by competing disorders. This is clinically significant because it will shape the nature of the treatment administered.

Symptoms of Drug Tolerance

The drug tolerance definition includes various symptoms. Some of the more common features of tolerance include:

  • Irreversibility, meaning that once this psychic damage develops, there is no known remedy that will enable the addict to revert back to a time before the establishment of tolerance.
  • Establishment of priorities in which drug-seeking or drug consumption takes precedence over other obligations.
  • The frequency of dosing increases, in addition to the quantities consumed, and the addict find themselves in a situation where the amount consumed on Monday no longer works by Friday.
  • Physiological tolerance also occurs when an organism builds up a resistance to the effects of a substance after repeated exposure. Ironically this can occur with environmental substances, such as salt or pesticides.

Drug Specific Causes

Complicating matters more deeply still is the fact that tolerance does not emerge in a standardized way; meaning that the process is as much dependent on the individual as it is the drugs the individual is taking. For example, a person who needs to take morphine to control post-surgical pain will likely develop tolerance (and Dependence) fairly quickly, without any regard for the intentions of the person taking the drug. The same person, if placed in a situation in which they were required to ingest sedatives such as Benzodiazepines, would develop tolerance as well, but guide the nuances of how the drug affects the body.

Classification of Tolerance Building Substances

It should be noted that all prescription medications are carefully regulated by the Federal Government with regards to prescribing protocols, which must be adhered to. This is especially true when dealing with major painkillers such as Oxycontin or Demerol. The government instituted what is referred to as a Scheduling System, which essentially rates a drug for its abuse potential. Schedule IV medications, which include substances such as blood pressure medication or insulin have virtually no abuse potential.

There exist four different stages of scheduling, with I being the most addictive. Drugs that are Schedule I medications are so abusable that the government considers them valueless and without medical efficacy. Heroin, Crack and Methamphetamine fall into this category. It should be noted again that drugs designed to treat chronic pain are highly addictive, and that there is a very real ratio between the painkiller’s effectiveness controlling pain and the intensity of the euphoria that is generated. Any analgesic or sedative will be proportionately as addictive as it is effective.

Rapid Tolerance Building Drugs

Opiates, which are the most common drugs doctors prescribe to treat pain, generate effects similar to those of opium or morphine and are highly addictive. These drugs include:

  • Hydrocodone (brand name Vicodin).
  • Codeine, which comes in varying strengths from I to IV.
  • Morphine (brand name MS Contin)
  • Oxycodone (brand name OxyContin)
  • Meperidine (brand name Demerol)

High Risk Populations

A fair question is who is at risk to develop tolerance. Most individuals who take pain medications in the manner consistent with what the physician orders do not become addicted to drugs nor do they exhibit tolerance (it does, however, happen from time to time). This scenario changes when dealing with someone for whom addiction is part of their history. In cases where a narcotic addict must take a painkiller for some procedure or condition are in for a very difficult time. People previously addicted to some medication in the past, or those with a family history of addiction to drugs or alcohol may be at increased risk of becoming addicted to narcotics.


  • The key to avoiding addiction is to take your medicine exactly as your doctor prescribes; not a moment too soon, and not doubling up on a dose if you missed one at dinner.
  • Share with your doctor any personal and/or family history of substance abuse or addiction. Your doctor needs this information to prescribe the medicines that will work best for you. Fears about addiction should not prevent you from using narcotics to effectively relieve your pain.
  • Remember, it is common for people to develop a tolerance to their pain medication and to need higher doses to achieve the same level of pain relief. Such a situation is normal and is not a sign of addiction. However, you should talk to your doctor if this effect becomes troubling.


The drug tolerance definition refers to the body’s ability governed by genetic factors and adaptive changes by the body. Adaptive changes occur in response to the repeated exposure to a particular drug. The result is usually a loss of sensitivity to the drug. This decreased response is tolerance.

Professionals say the drug tolerance definition is as a state of progressively decreased responsiveness to a drug. Consequently, a larger dose of the drug is necessary to achieve the effect originally obtained by a smaller dose.


There are two types of drug dependence.

Physical Dependence

Physical dependence is a condition in which the body has adjusted to the presence of a drug. This results in clear symptoms of withdrawal when its use stops. In extreme cases, rapid withdrawal can be life-threatening because the body has become so dependent on the drug as to interfere with normal body processes.

An individual physically dependent on a drug requires that drug in order to function normally. Physical dependence is associated with tolerance in most cases. The state of physical dependence is revealed by withdrawing the drug and noting the occurrence of withdrawal symptoms sometime after the drug is withheld. The symptoms of withdrawal can be terminated by re-administration of the drug.

Symptoms of drug withdrawal tend to be the opposite of the effects of the drug. If the effect of the drug is sedation, the withdrawal effect will likely be hyper-excitability. If the effect was stimulation the withdrawal effect will likely be emotional depression.

Longer-acting drugs tend to produce less intense withdrawal symptoms because the body has more time to adapt to the decreasing presence of the drug.

Psychological Dependence

Professionals characterize this kind of dependence by the emotional and mental preoccupation with the drug’s effects and by a persistent craving for it. The symptoms displayed are not physical symptoms. Craving seems to be the most common withdrawal symptom.

Psychological dependence usually manifests from compulsive drug-taking, but the frequency and pattern of use can differ considerably from one individual to another.


This is the ability of one drug to suppress the manifestations of physical dependence produced by another and to maintain the physically dependent state. Cross-dependence may be partial or complete. One amphetamine will show cross dependence with other amphetamines. Most sedatives show cross dependence with each other and with alcohol. Cross-dependence usually occurs among compounds of a given family of drugs. However, it may also occur among drugs of different families that have similar pharmacological effects.


Addiction is a difficult word to define. The World Health Organization (WHO) has provided the following definition: “A behavioral pattern of drug use, characterized by overwhelming involvement with the use of a drug (compulsive use), the securing of the supply, and a high tendency to relapse after withdrawal. Professionals view addiction as an extreme on a continuum of drug use patterns. It refers, in a quantitative rather a qualitative sense, to the degree to which drug use pervades the total life activity of the user, and to the range of circumstances in which drug use controls his/her behavior.”

Addiction refers to dependent patterns of drug self-administration without making a distinction between physical or psychological dependence. People often imply moral weakness by the term addiction.

The WHO suggests that the term “drug dependence” should replace the term “addiction.” It is not possible to identify with precision the point where compulsive use turns to addiction.

The term addiction cannot be used interchangeably with physical dependence since one can be physically dependent on drugs without being addicted and – as stated elsewhere – in some cases, addicted without being physically dependent.

Self-administration of drugs:

  • The properties of the drug itself.
  • The route of administration.
  • The size of the individual dose.
  • The amount of work required to obtain a dose.
  • The presence of other drugs.
  • Previous experience with other drugs.

Scientific studies show that pre-existing mental and behavioral disorders are not a prerequisite for drug use. They also show that the drugs themselves are powerful reinforces, even in the absence of physical dependence. This discovery radically alters how we treat addiction. In addition, it affects many of the assumptions we make with regards to the expression of its pathology.


At the Authentic Recovery Center, we offer multiple types of addiction treatment services for co-occurring disorders and addiction. This includes inpatient and outpatient rehab options. With a program focus on the underlying issues that contribute to scenarios from which drug tolerance develops, we provide a platform for sustainable recovery and change. Remember, “The only failure in life is the failure to act.” Now that you know the drug tolerance definition, you can act. If you are interested in learning more about the Authentic Recovery Center, contact us at 866-256-0051.

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