Substance Use Disorder

Addiction and health
Substance use disorder (SUD), commonly referred to as ‘addiction’, can be perceived as ‘taboo’ and surrounded by stigma. But the fact of the matter is, SUD is complex and there are so many forms it can take — a single blog would not do the topic justice. As pharmacy students and future pharmacists, it is likely that we will meet patients with SUD, so it is of paramount importance that we have knowledge of the condition. This blog will focus on SUD in relation to the following substances: opioids, alcohol and tobacco.

Substance use disorder
The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) — the handbook used by health care professionals in the United States and around the world as the authoritative guide for the diagnosis of mental disorders — describes SUDs as a part of a class of disorders known as substance-related disorders. Substance-related disorders include 10 separate classes of drugs, 9 of which have been attributed to SUD.¹,²

The British Medical Association (BMA) defines SUD as the repeated use of a psychoactive substance/s, such that the user tends to be periodically or chronically intoxicated, displays a compulsion to take the substance/s and finds it extremely difficult to cease taking the substance/s; demonstrating a determination to acquire the psychoactive substance/s by ‘almost any means’.³​

Substance use disorder can often stem from drug misuse, whether intentional or unintentional.³ Drug misuse is the ‘use of a substance for a purpose that is not consistent with legal or medical guidelines’.³ In other words, the use of a drug that goes against medical advice or the law. The term ‘drug use’ is sometimes used instead of ‘drug misuse’ by healthcare professionals as it is perceived to be less judgmental and will be the term used in this blog.³

SUD related to drug use is the compulsive need to take a drug that can be difficult to control, despite the person being aware of the negative consequences of its usage.⁴ When a person takes a psychoactive drug, the reward circuit of the brain releases dopamine and produces feelings of elation.⁴ The dopamine release reinforces the feelings of pleasure, which gives the drug the ability to be addictive.⁴ SUD  can even be initiated by as-prescribed use of a drug, as repeated drug use can change the brain’s biochemistry such that the brain’s ability to resist compulsion for the drug is challenged, resulting in a harsh cycle of recovery and relapse.⁴ 

The impact of drugs use is significant. It has been associated with poor physical and mental health, as well as death, unemployment, homelessness, family breakdown and criminal activity.⁵ In fact, drug use is the third most common cause of death for those aged 15 to 49 in England.⁵ This reveals the pressing need to help people quit drug use in an effort to improve and preserve the lives of these individuals and better society as a whole.
 
Opioid use disorder
Opioid use disorder (OUD), also known as ‘opioid dependence’ is defined in the DSM-V as “…a problematic pattern of opioid use leading to clinically significant impairment or distress…”² A joint paper by the World Health Organization (WHO), The United Nations Office on Drugs and Crime (UNODC) and the United Nations AIDS division (UNAIDS) states that: ‘substitution maintenance therapy is one of the most effective treatment options for opioid dependence.’⁷ The type of substitution maintenance therapy can vary between countries and even between patients. In the United Kingdom (UK), The Royal Pharmaceutical Society (RPS) supports methadone treatment as a maintenance treatment to recover from and overcome OUD, stating that methadone is ‘not a cure for addiction’  but is a ‘safer alternative’ to the use of illicit opioids such as heroin.⁸ However, the RPS recognises the limits of methadone treatment in the long-term, and so supports a holistic approach where methadone or newer therapies such as buprenorphine are combined with other interventions such as psychosocial interventions to help drug users recover from OUD.⁸

In the United States (US), OUD has been linked to the misuse of prescription opioids.⁶ In fact, in 2016, 11.5 million Americans self-reported that they had personally misused prescription opioids in the previous year.⁶ Medication-assisted treatment (MAT) is considered the Gold Standard treatment option for OUD in the US.⁶ MAT for OUD is the use of one of three medications, namely buprenorphine, naltrexone, or methadone in combination with psychosocial and/or behavioural therapy.⁶ OUD is also a concern in Australia, with heroin the 4th most common principal drug of concern in 2016–17.⁹  One of the main treatment types used for OUD in Australia is opioid pharmacotherapy which involves regular use of a legally obtained, longer-lasting opioid, examples of which are methadone, buprenorphine or buprenorphine-naloxone.⁹

Tobacco use disorder
When we think of the long-term effects of smoking tobacco, people may immediately jump to lung cancer as the major condition- and they aren’t wrong. Smoking is the cause of 7 out of 10 lung cancer cases, and it can also cause or worsen other lung conditions like asthma and chronic obstructive pulmonary disease (COPD).¹⁰ But what many people don’t realise is that it can cause a whole array of other conditions, including many cancers like liver and pancreatic cancer, and also increase the risks of heart attack and stroke in otherwise healthy individuals.¹⁰ Smoking causes around 100,000 deaths in the UK alone each year.¹⁰ With these facts in mind, it’s understandable that 50% of smokers try to quit each year.¹¹ Despite this, only 6% of smokers manage to quit smoking in a given year.¹¹

When a person smokes a cigarette, nicotine binds to cholinergic receptors to release dopamine, causing an elated sensation while reducing stress.¹¹,¹² Over time, the receptors become desensitised and nicotine levels in the body decline, causing the person to feel withdrawal symptoms like irritability and anxiety.¹¹,¹² These symptoms, alongside other factors like environmental stressors and smoking cues, add to the craving urges the person experiences to continue smoking.¹²

Although the number of smokers continue to drop annually due to the decreasing appeal of smoking and improvements in health education, there is still a substantial subset that smokes regularly (14% for the UK in 2019).¹³ As future pharmacists, we will be in a position to help people quit smoking and lower the number of people with tobacco use disorder further. Smoking cessation programmes are offered by some pharmacies in the UK.  One key service is the promotion of nicotine replacement therapy, where nicotine formulations like patches and gums are offered to patients in the event that they are considering or trying to quit.

In addition, an important campaign that pharmacies promote in the UK is Stoptober, where smokers are encouraged to quit smoking for 28 days during the month of October.¹³ In 2019, 25% of smokers nationwide attempted the challenge, with 8% continuing to abstain after the four weeks, suggesting that this campaign does have an impact on the smoking population.¹³ In North Carolina the programme QuitlineNC is also available as a free smoking cessation service, which provides 24/7 telephone and online coaching.¹⁴ In Victoria, the programme Quit offers a hotline where smokers can access a trained counsellor to speak to for advice and support, as well as access to regular texts that offer encouragement in their journey.¹⁵

Alcohol use disorder 
Alcohol is often portrayed by the media as a ‘glamorous’ or an ‘exciting’ thing to have on a night out with friends. It is possible that due to this association, people don’t usually link its consumption with addiction. When people drink alcohol, they tend to  feel more fun, confident or relaxed, as alcohol stimulates dopamine release.¹⁶ However, this can also cause people to become psychologically dependent on alcohol, where they feel that they need a drink- this is the basis of alcohol use disorder (AUD), also called ‘alcohol dependence’.¹⁷ Another sign of AUD is worrying about when the next drink will be available and wanting a drink in the morning.¹⁷ This psychological reliance also results in physical dependence where people develop shakes, sweats and feel nauseous and anxious without a drink.¹⁷ Over time, this leads to long term effects like hypertension, heart disease or liver disease, so identifying when a patient needs treatment is essential in helping them avoid these effects.¹⁸ The Alcohol Use Disorders Identification Test developed by the World Health Organisation is available for people worldwide to use to identify if an intervention is needed, with a score of 8 or more indicating hazardous alcohol use.¹⁹

Many UK pharmacies display educational posters explaining that adults should not drink more than 14 units of alcohol a week, with half a pint of beer being equivalent to 1 unit and a small glass of wine being 1.5 units.²⁰ There are also many leaflets available with the contact details of support groups such as Alcohol Change UK, Alcoholics Anonymous in the US and SMART Recovery in Australia. Patients identified as heavy drinkers are encouraged to cut back by having several alcohol-free days per week, and to set a limited budget per week to spend on drinks.²⁰

If the addiction is severe enough to warrant an intervention by a healthcare professional, inpatient treatment is offered at licensed treatment centres.²¹ Monitored detoxification treatment is given to the patient, after which patients recover in residential treatment centres. This is where they can be put on medication-assisted therapy in order to stay sober and avoid relapsing.²¹ The most common drugs used are disulfiram, which stops the body from metabolising alcohol, acamprosate, which prevents alcohol cravings, and naltrexone, an opioid antagonist, which also prevents cravings.²² Disulfiram, a carbamate derivative, interacts with the acetaldehyde found in alcohol and causes it to build up in the patient’s body if alcohol is consumed, causing them to experience symptoms like nausea and vomiting, sweating and headaches.²²

Other drugs which can be used include antipsychotics, where the alcohol use is associated with mental illness, and clonidine, an antihypertensive which helps by reducing the side effects caused in the detoxification process such as hot flashes. Anticonvulsants and beta blockers can also be used off-label in treating alcohol use disorder.²²

SUD is difficult to define, and even more difficult to treat. Although drug therapies are available to help treat this condition, these are typically offered in conjunction with other therapies (such as counselling) for a more holistic treatment. Pharmacists and pharmacy teams have a role to play in helping individuals overcome the types of SUD described in this blog, and as pharmacy students, we will come across patients battling this condition - if not now than in the future as qualified pharmacists - and the more informed we are about the condition, the better help we will be. 

Written by: Nusayba Ali and Amelia Ryan

References:

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2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Washington, DC: American Psychiatric Association; 2013. 541-46.
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