Introduction

If you suffer with chronic pain or any pain which has remained or recurred for more than 3 months, you are not alone as millions of people around the world are also going through similar experiences. Chronic pain can negatively impact one’s life and while there are many different painkillers and management advice available to you, it is understandable to seek alternative options if they do not provide significant relief. Cannabis, a drug legal in some areas across the world and illegal in others such as the UK with exceptions, has been used for medical reasons for many years as an alternative pain management option.^1-4 However, using cannabis carries a risk of drug dependency and it is important to understand this if you are considering its use or are already using it, to be able to make informed health decisions.⁵

Cannabis as a treatment for chronic pain

Cannabis the plant known by many names such as marijuana and weed, contains multiple substances called cannabinoids such as cannabidiol (CBD) and tetrahydrocannabinol (THC), which can be extracted or made synthetically into recreational or medicinal products.^5,6 

It can be available in various forms for use and can be ingested by:¹

• Smoking
• Vaping
• Eating
• Applying on the skin

When you ingest these substances, they interact with the body’s systems but not all of the substances cause the same effect in the body.^4,5 Whether medical cannabis is able to provide pain relief has been debated and research has produced inconsistent results. For example, one large study found that a high number of patients taking medicinal cannabis for chronic pain have reported pain relief and reduced use of other painkillers.⁴ Whereas another large study which conducted interviews with patients taking cannabis found no evidence of these effects, with some patients experiencing more pain.⁷

Despite the conflicting information regarding whether cannabis can provide pain relief, as with any product you take, there is a risk of unpleasant reactions. In the case of cannabis, some of side effects you may experience are:^4,5

• Anxiety
• Worsened mental health conditions such as depression and schizophrenia
• Feeling or being sick
• Palpitations
• Confusion
• Seizures
• Memory loss
• Diarrhoea
• Impaired attention
• Inability to process information
• Sweating

Understanding cannabis dependency

Another major side effect of cannabis is dependency, so you may find yourself relying strongly on the drug to manage the chronic pain and to be able to go about your day more comfortably.⁶ Drug dependence can be categorised into both physical and physiological dependence.

Physical dependence

Physical dependence is where you experience withdrawal symptoms when you stop taking the drug and the drug is no longer in your body.⁶ For cannabis, some of the withdrawal symptoms are:⁶

• Irritation and anger
• Sleep problems
• Feeling sick
• Feeling uneasy
• Weight loss
• Tiredness
• Body pains

Physiological dependence

Physiological dependence is when there is a change in your mental or emotional state, where your body craves the drug and believes it needs the drug to function.⁶

You may experience both categories at the same time as they are linked.

There is a difference between drug dependence and addiction as an addiction is when you have extreme cravings or lose control of your  drug use regardless of how negatively it may be impacting you or your life.⁶

How can cannabis dependence be measured?

Some criterias can be used to determine if an individual is dependent on cannabis, and some examples of criterias used in America is detailed below and is taken from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) publication.⁶ Although it should be noted that the criteria in DSM-5 assess cannabis dependence together with addiction under one term called cannabis use disorder.⁶ The criteria covers topics surrounding:⁸

• The frequency or quantity of cannabis used
• Cravings
• Failed attempts of quitting cannabis use
• Time spent conducting cannabis-related activities such as acquiring or using the drug
• Neglect of the individual’s life
• Continued use despite harm to the individual’s life
• Tolerance
• Withdrawal symptoms

Risk factors specific to chronic pain patients

There are a few risk factors described below that may make someone more sensitive or increase the likelihood of cannabis dependence when used in treating chronic pain. These risk factors are:

• Cannabis type

It has been stated that depending on the type of cannabis-based substance you take can influence your risk of dependency. For example, THC-based substances have been said to be more likely to cause cannabis dependence whereas CBD has a lower potential.⁹ 

• High doses⁶
• Aged below 18 years old
• Length and frequency of cannabis use

Due to the long-lasting nature of chronic pain, individuals are likely to use cannabis regularly, for a prolonged period of time and/or increase the dose which contributes to the risk.⁹

• Other health conditions

Research has found that mental health conditions can increase cannabis dependence and those with chronic pain are more likely to suffer from mental health conditions.⁹

• Genes passed down through the family

There is evidence that cannabis dependence can be inherited in your family and some specific genes have been associated to the condition.^5.9

Although some of these risk factors may be difficult to mitigate, others can be reduced or taken into consideration before using the drug including using specific types of cannabis substances, limiting the quantity of the cannabis substance, and perhaps avoiding its use if you have mental health conditions. Also, seeking advice from a healthcare professional will be useful in guiding it’s use.

If this article has brought your attention to cannabis dependence and you feel you may be experiencing it, there is support available to you. There is advice and information available online and in health centres, treatment centres. Additionally, you can call helplines to understand your options, and you can utilise charities and support groups to interact with others going through similar experiences to you and more. The support offered can also be given confidentially so please access the support you need without hesitation. 

FAQ

What should I do if cannabis is effective for my chronic pain but I am worried about cannabis dependence?

The first point of call would be to explain these worries to a healthcare professional who can assess you for cannabis dependence, help you to monitor your useage, suggest alterations to your dose and work with you to find alternative options if needed. 

Summary

The use of cannabis for medical reasons has been done for many years but it has also increased with some countries relaxing their laws surrounding its use. Although the research on the effectiveness of cannabis on chronic pain has not been clear, it is important to understand the risks of dependency if you choose to use it. Cannabis dependence can be physical or physiological but it should not be confused with addiction. There are methods to detect dependence and some individuals may be at an increased risk of developing it such as those continuously using cannabis for a prolonged period or those with mental health conditions. More research is needed in cannabis dependence for those with chronic pain however, it is important to understand the known risks before using this drug and seek the necessary help if you need it.