Tolerance

Tolerance vs. dependence

Although the word “tolerance” is sometimes used interchangeably with dependence and addiction, they are not synonymous terms: 

• Tolerance refers to the decreasing effect of the same drug dose over time.
• Dependence refers to a biological adjustment to the presence of a drug over time, meaning that suddenly stopping the use of a substance will result in withdrawal symptoms. 
• Addiction refers to a medical disorder in which someone uses a substance (or non-substance) to achieve a temporary reward (such as a euphoric high) despite negative effects. Like tolerance and dependence, addiction can develop after repeated use of some substances. 

Social tolerance is the acceptance of—or lack of interference with—differences, even though one considers them wrong or incorrect. For example, a spouse can tolerate their partner’s taste in music, and a parent can tolerate their child’s career choice.  

For tolerance to exist, there must be a disagreement or difference of opinion. Although the tolerant person may negatively view the difference, they respect the right of the other person to have different beliefs or practices.

As described in the Stanford Encyclopedia of Philosophy, the understanding of what it means to be tolerant can differ. The following four concepts summarize various historical understandings of tolerance: 

• Permission conception: This definition defines tolerance in the majority group when it allows minority groups to adhere to different beliefs, identities, or practices in personal life, as long as they accept the dominant views of the majority in public settings. This definition is frequently used in Western societies in relation to immigrant groups. 
• Coexistence conception: In groups of similar power, coexistence conception refers to practicing peaceful coexistence and compromise as an alternative to conflict. This definition emphasizes that intolerance disrupts peaceful coexistence.  
• Respect conception: This definition is based on the belief that all people are moral-political equals, even though they differ in their cultural practices and beliefs.  
• Esteem conception: Under this definition, tolerance requires that people be respected as equals and that their differences be regarded as ethically valid, even though they are not adopted.

Regardless of how it’s defined, social tolerance can promote human rights and reduce discrimination based on identity, religion, ethnicity, race, culture, beliefs, and traditions. 

Tolerance is valued as a means of both . In 1996, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) declared November 16th the International Day for Tolerance, stating that, “Tolerance recognizes the universal human rights and fundamental freedoms of others. People are naturally diverse; only tolerance can ensure the survival of mixed communities in every region of the globe.” Tolerance does not demand a lesser level of commitment to one’s beliefs or values. Instead, tolerance emphasizes the elimination of discrimination.  

Drug tolerance develops when the same amount (dose) of a drug produces a reduced response compared to past use. Typically, tolerance occurs when someone has been using a substance for an extended period.

The following substances are some examples of medications that may cause drug tolerance to develop: 

• Alcohol
• Antidepressants
• Antihistamines (allergy medications) 
• Anti Anxiety medications
• Opioids
• Benzodiazepines
• Corticosteroids

In general, tolerance develops when the body tries to adapt to the presence of substances that are chronically present. However, there are different types of drug tolerance that can occur depending on the type of substance used: 

• Pharmacodynamic tolerance: This type of tolerance involves desensitization to substances. It develops when cell receptors and enzymes in the body that previously responded to the substance become less sensitive, making the substance less effective. Pharmacodynamic tolerance commonly develops in response to opioid use. 
• Metabolic tolerance: This type of tolerance occurs when the body starts metabolizing substances more efficiently, leading to reduced effects. This type of tolerance commonly develops with repeated alcohol consumption. 

Substance tolerance can be dangerous, increasing the risk of: 

• Negative health effects: Taking high doses of substances can increase the risk of health effects. For example, when someone with alcohol tolerance drinks larger quantities of alcohol, they can increase their risk of high blood pressure, liver disease, certain types of cancer, dementia, and depression. 
• Dependence: Physical drug dependence occurs when the body adjusts to the presence of foreign substances, creating a new “normal” state of functioning. If dependence develops, reducing or eliminating the use of substances can create a state of imbalance, resulting in withdrawal symptoms. Dependence is more likely to develop in people who take increasingly large doses of substances. 
• Addiction: Not all substances are addictive, but for those that are, taking larger doses can increase the risk of addiction, which is a psychiatric disorder.  
• Overdose: When people develop substance tolerance, they usually need more of a drug to feel the same effect. Tolerance is something that can change, and with lower tolerance, a person could be at higher risk of overdose without realizing it. The following can reduce tolerance: 
• Taking a break or stopping the use of a substance 
• Reducing substance use, even by a small amount or for a short time
• Altering the method of drug delivery (such as changing from injection to oral ingestion, or from inhalation to injection)
• Changing the type of substance used
• Using substances that are not as potent as substances previously used
• Having interrupted availability of substances
• Changes in substance strength or purity
• Experiencing illness or stress