Substance Use Disorder (SUD): Definition, Symptoms & Treatments

Published On: April 5, 2024

Problems with drugs and alcohol aren’t always what we see on TV.

There are many addictive substances. Not all of them are illicit drugs, and some are even available over the counter.

Substance use disorders range from recreational drugs to prescription medications, and sometimes you may not even know you have a problem until it’s too late.

But substance use disorder is treatable, and there are many resources and support groups available to help.

What is Substance Use Disorder?

A man with substance use disorder looking away

Substance use disorder (SUD) is defined in research as ‘a treatable mental disorder that affects a person’s brain and behaviour, leading to their inability to control their use of substances like legal or illegal drugs, alcohol, or medications.’[1]

Symptoms can be moderate to severe, with addiction being the most severe form of SUD.

Substance use disorder is a medical condition that should be treated with seriousness.

SUD is different to substance misuse. Substance misuse involves taking substances occasionally without it becoming a habit or pattern of use.

You can find reliable information from the National Institute on Drug Abuse.

What is the Difference Between Substance Use Disorder and Addiction?

A woman completing an assessment of substance use disorder with a clipboard

Substance use disorder is an umbrella term for drug abuse, dependence, and addiction.

The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders from the American Psychiatric Association) criteria includes:

  1. You use substances in larger amounts or over a longer period than was intended
  2. You have intense cravings, or struggle to cut down
  3. A lot of your time is spent getting hold of, taking and recovering from a substance
  4. Your usage has resulted in you struggling to fulfil major role responsibilities at work, school or home
  5. Use of the substance is causing problems in your relationships
  6. You prioritise using the substance over engaging in social, occupational or recreational activities
  7. You use the substance even in dangerous scenarios, such as driving
  8. You use the substance despite knowing that it harms your health and life
  9. You’ve developed a tolerance, and need more of the substance to get the same effect
  10. You experience withdrawal symptoms when you try to stop or cut down[2]

What is the Most Common Substance Use Disorder?

Patient leaning on a fence and thinking

The most common substance faced by people in treatment is alcohol.[3]

What Other Common Addictive Substances?

  • Prescription and non-prescription stimulants – Adderall, cocaine, methamphetamine
  • Tobacco/nicotine – cigarettes, e-cigarettes, vapes
  • Alcohol
  • Caffeine
  • Cannabis – (marijuana)
  • Hypnotics – sedatives, anxiolytics, sleeping pills, benzodiazepines, barbiturates
  • Hallucinogens – PCP and LSD
  • Inhalants – paint thinners, aerosol sprays, gases and nitrites (poppers)
  • Prescription and non-prescription opioids – codeine, oxycodone, heroin

How do I Know if Someone is Intoxicated?

Two people holding hands across a table

Signs of Alcohol intoxication

As the drunken person gets more intoxicated, they can progress through:

  • Being more talkative – speaking louder
  • Uncharacteristic poor judgement of social norms – foul language, flirtatiousness, off-colour jokes
  • Physical impairment – unfocused eyes, slurred speech, forgetfulness, slow movements, slurred speech, losing balance[4]

Signs of Other Types of Drug Intoxication

Two people looking sociable at a bar

Drugs can have a different effect depending on the substance.

This can generally include:

  • Increased energy and confidence – loss of inhibitions
  • Loss of coordination – trembling, twitches
  • Enlarged pupils – bloodshot or glassy eyes
  • Irritability – moodiness, paranoia (being extremely suspicious) – aggressive behaviour
  • Hallucinations – hearing and seeing things
  • Exhaustion – fatigue or insomnia
  • Changes to eating patterns – eating less or more
  • Sickness – nausea and vomiting, stomach cramps, blurred vision, headaches or dizziness
  • Anxiety – panic attacks, dizziness, sweating, dry mouth, muscle aches and headaches[5]

Who Does Substance Use Disorder Affect?

A diverse group of people with substance use disorders

Substance addiction affects the lives of people from all ages, genders and backgrounds. But there are some trends across the UK.

In 2023, The Office for National Statistics reported that drug use was higher among 16-24 year olds.[6]

How Common is Substance Use Disorder?

Data from 2023 people found that of people aged 16-59:

  • 9.5% reported using a drug in the last 12 months
  • 7.6% reported using cannabis
  • 3.3% reported using a class A drug

This is higher than ten years ago, which suggests drug use has gone up.[7]

What Are the Signs and Symptoms of Substance Use Disorder?

A man sweating withdrawing from substance use disorder

Some of the common symptoms of SUDs are:

  1. Clinically significant impairment
  2. Health problems
  3. Disability
  4. Failure to meet major responsibilities at work, school, or home[8]

How Does Substance Use Disorder Develop?

A brain and neurons

Substance use disorder is something you may have initially experimented with for fun. It may be a prescription drug you took a few times at first.

After a while, you may have noticed you’re struggling to go without it, and that it takes up more and more of your thoughts, time and life.

So how does a substance take hold of us?

Brain Chemistry

Brain imaging studies show that our brains experience an increase in dopamine (a hormone that makes us feel happy, satisfied and motivated) when we drink alcohol, or take another substance like nicotine.[9]


Parent and child family

Research shows evidence that our genes can make more or less likely to develop an addiction, including SUDs and gambling.[10]

Mental Health Conditions

Science has shown a link between mental health disorders and addiction.

People with poor mental health such as depression, anxiety and PTSD sometimes use drugs or alcohol to try to cope with their symptoms. This is known as self-medicating.[11]

Access and Exposure

Teenage boy walking down road with backpack, head down

Scientists have theorised that drug use may be increased by socialising, especially if the surrounding people are also using drugs.[12]

Adverse Childhood Experiences

Adverse childhood experiences are events experienced as a child that have the potential to cause trauma.

These commonly include violence, abuse, and being raised in a family with mental health disorders or substance use problems.

There is a link between people who have experienced adverse childhood events and increased substance use disorder.[13]

How is Substance Use Disorder Diagnosed?

Therapist doing an assessment

You should see your GP or contact a treatment centre for an official diagnosis.

There are official tests used when diagnosing addiction. One of these is the DSM-5.

DSM-IV and DSM-5 Criteria for Substance Use Disorders

The criteria are:

  1. One or more abuse criteria within a 12-month period and no dependence diagnosis; applicable to all substances except nicotine, for which DSM-IV abuse criteria were not given
  2. Three or more dependence criteria within a 12-month period
  3. Two or more substance use disorder criteria within a 12-month period
  4. Withdrawal not included for cannabis, inhalant, and hallucinogen disorders in DSM-IV. Cannabis withdrawal added in DSM-5[14]

What is the Treatment for Substance Use Disorder?

A woman taking a white pill during SUD withdrawal


Detox for substance use disorder is a set of interventions which manage intoxication and withdrawal.

The aim is to clear toxins from your body, or minimise harm caused if you’re not yet abstinent.[15]

There are medications available for many physical withdrawal symptoms, which make coming off drugs or alcohol safer and more comfortable.

A qualified healthcare professional should assess your medical history and risk factors before prescribing any medication.


Two women discussing acceptance and commitment therapy for addiction

There are so many therapies available which can treat both substance use disorder and any co-occurring mental illness.

Below are just some of the options available to you:

Cognitive Behavioural Therapy

CBT is a popular therapy which looks at understanding and improving your thought patterns and how they impact your behaviours.

Dialectical Behaviour Therapy

DBT is a talking therapy which focuses on your emotions. You’ll learn how to accept your feelings, and learn skills to manage them in order to make positive changes in your life.

Group Therapies

Group therapy will see you discuss your feelings and behaviour with others who are going through the same struggles.

Some people find that a support network and shared experience helps them to gain a deeper insight into their problems, and develop connections for a strong support network.

Contingency Management

A woman holding a gift with a topper

Contingency management focuses on positive reinforcement for small achievements, like offering rewards for reaching a milestone in recovery or attending a counselling session.

Family Therapy

Family therapy helps families with alcohol and drug use problems look at and understand influences on drug use patterns, and improves general family dynamics.

Motivational Enhancement Therapy

MET looks at your intrinsic motivation to change, and structures therapy around reminding you of these goals.

Twelve-step facilitation (TSF)

12 weekly sessions will be offered to you one-to-one with the aim of becoming engaged in 12-step mutual support programs like the AA. These are good complementary support.

The twelve steps focus on acceptance, surrender, and active involvement in recovery.

Holistic Therapies

Holistic therapy can give you a chance to engage in an activity you find rewarding. This includes equine therapy, art therapy, music therapy and many others.

Doing something you’re good at can boost your self esteem and help you find a hobby.

If you find talking difficult, holistic therapy can take the pressure off, and let you express yourself in a way that comes more naturally.

How Can I Prevent Substance Use Disorder?

Three people smiling with a playful pose with organisation shirts on

  1. Understand how substance abuse happens – by using, seeking out and abusing alcohol, or recreational or prescription drugs
  2. Avoid temptation – stay away from friendships or relationships where SUDs are prevalent
  3. Get help for your mental health – this will keep your mind strong and ensure you don’t turn to substances to cope
  4. Recognise which substances are addictive – and be cautious when using them
  5. Create a well-rounded life – when one part of your life goes wrong, it helps to have other aspects that are meaningful to fall back on[16]

How Easy is it to Recover from Substance Use Disorder?

A woman smiling at another, holding a smart device

Factors that determine how easy it will be for you to recover include:

  • Age –the younger you are, and the sooner you tackle the issue, the easier you may find it to change your behaviours
  • Drinking habits – the more disordered your drinking, the more help you may need
  • Social stability – having a good support system can give you a better chance of recovery
  • Motivation – having a strong willingness to change will help you greatly – this can be boosted with treatment
  • Diagnostic category – the more severe your addiction, the more help you may need to fully recover[17]

It’s important to remember that recovery is possible for everyone, and that help is available.

What Are the Possible Complications of Substance Use Disorder?

A doctor typing on a keyboard with a stethoscope to her side

Health Consequences of SUA

Common health issues include:

  • Cancer – consuming harmful toxins
  • HIV/AIDS – sharing needles or engaging in unsafe sex
  • Cardiovascular disease – putting a strain on your heart
  • Stroke – lowering your body’s natural defences
  • Hepatitis B and C – sharing needles
  • Lung disease – consuming pollutants
  • Mental disorders – changing your brain’s natural chemistry[18]

Family and Social Consequences of SUA

Parent and child family

Families and relationships can be affected by:

  • Adverse events for children – trauma, neglect, and mental health problems
  • Emotional problems – anxiety, anger, fear, shame and guilt
  • Money problems – spending money on substances
  • Marital and relationship breakdown – tension and conflict

Work Consequences of SUA

Your job prospects could be disrupted by:

  • Sickness leave – time off intoxicated or recovering from substances
  • Poor performance – low motivation, concentration, and accuracy
  • Being fired – failing to meet standards
  • Unemployment – struggling to find a job

How Can I Help a Loved One with Substance Use Disorder?

One man with his hand on another's shoulder in support

It can be really difficult to love someone who you can see is struggling with substance use disorder.

Some of the ways you can help are:

Build a Support Network

A support system of people who can help is a vital coping strategy to keep your loved one on track.

If agreed with all people, you could set up regular check-ins or go together to support meetings.

Those who live with your loved one can ensure they keep to rules to ensure their space is free from relapse triggers – like old friends who may not support sobriety, and any substances.

Seek Psychological Treatments

Therapy and addiction counselling can greatly increase chances of a successful recovery.

Behavioural therapies can also enhance the effectiveness of medication.[19]

If your loved one is open to receiving this kind of help, you can look into therapy together. Some will also allow you to attend.

Find Out if Medication is Necessary

Two men talking at a table

Medication isn’t necessary for behavioural addictions, however some substance use disorders result in chemical changes in the brain.

Medication will help your loved one to go through withdrawal safely and without too many unpleasant symptoms.

Physical addictions include:

  • Tobacco
  • Opioids
  • Alcohol
  • Prescription drugs
  • Cocaine
  • Amphetamines
  • Marijuana
  • Hallucinogens

Find a Prevention

During treatment, your loved one should learn coping mechanisms, that will help them into their future to keep relapse triggers at bay.

Many rehabs offer aftercare services like recovery management check-ups, where they’ll receive regular telephone calls or face-to-face meetings to keep them on track.

How Do I Live with Someone with SUD?

A dog looking out of a window

It can be scary, draining and frustrating living with someone who has a substance use disorder.

Remember to:

  1. Look after yourself – you can only help others when your own mental health is strong
  2. Seek therapy if you’re struggling – SUDs can take a mental toll on families and households too
  3. Set boundaries – say no to substances in the house or friends who enable this
  4. Check you’re not enabling – don’t try to hide, take on responsibilities or pay for your loved one

Are There Any Support Groups for Loved Ones of a Person with SUD?

There are many support groups across the UK. The charities listed below offer help for people in addiction, as well as their friends, families and carers.

  • FRANK – support for people who use drugs or alcohol and their parents or carers
  • Alateen – help for teenage family and friends of alcoholics
  • Al-Anon – an open space for loved ones of people with alcoholism to meet and share a common bond
  • Families Anonymous – online and face-to-face support meetings for the family and friends of people facing any substance use disorder

Intervention for Substance Use Disorder

An intervention for substance use disorder with people sitting in armchairs

Intervention for substance use disorder is a process where those who are close to the addicted person, confront the issue, talk about how it’s impacting everyone and offer options.

Sometimes people receive help from a professional interventionist.

During the intervention, you should seek to see how willing your loved one is to change. If they will consider the possibility, you can go their options and begin the first steps to getting treatment from a healthcare provider.

If they’re resistant, know that you cannot force them, and that you’ve done what you can at this moment in time.

How Else Can I Get Help for Substance Use Disorder?

A person using a phone and laptop

Rehab 4 Alcoholism’s helpline can provide you with advice completely free of charge.

Once you or your loved one are ready, we can let you know what your options are for rehab, and facilitate a referral to a top-quality facility.

For more information about substance use disorder, call the 24/7, confidential hotline on 0800 111 4108.






















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