Substance use disorders are a range of mental health conditions that develop when people use drugs or alcohol in a way that damages their health, relationships and ability to function. They involve compulsive use, withdrawal symptoms and long-term harm to the body.
They fall into three broad categories: alcohol-related disorders, drug-related disorders and other substance-related disorders. Each has its own symptoms and its own treatment pathway.
Some substances carry a higher risk than others. Cocaine and methamphetamine are among the most habit-forming, though alcohol accounts for the greatest share of admissions in South Africa.
The goal of treatment is to help a person stop using and maintain their sobriety over the long term. What that treatment looks like is set out further down this page.
Understanding the signs, causes and treatment of these disorders matters, because early recognition changes the outcome.
Types of Substance Use Disorders
Substance use disorders are conditions defined by the harmful use of, or reliance on, chemicals that damage physical and mental health. The DSM-5-TR groups them by substance class.
| Substance class | What the disorder involves |
|---|---|
| Alcohol | Excessive, problematic drinking that continues despite harm to health, work and relationships |
| Cannabis | Heavy or daily use that affects motivation, memory and daily functioning |
| Hallucinogens | Persistent use of substances such as LSD or psilocybin despite psychological consequences |
| Inhalants | Misuse of volatile substances such as solvents, glues and aerosols |
| Opioids | Dependence on prescription painkillers or on heroin, with strong physical withdrawal |
| Sedatives, hypnotics and anxiolytics | Dependence on benzodiazepines and sleeping medication, where stopping abruptly is dangerous |
| Stimulants | Misuse of cocaine, methamphetamine or prescription stimulants, often with psychiatric symptoms |
| Tobacco | Nicotine dependence, the most common substance use disorder worldwide |
Other substances not specifically listed can also produce a substance-related disorder. The diagnosis follows the pattern of use and its consequences rather than the name of the drug.
Causes of Substance Use Disorders
Substance use disorders are complex conditions with several underlying causes, usually acting together rather than alone.
Genetic vulnerability plays a significant part. Research shows certain genetic factors increase susceptibility to addiction by affecting how the brain responds to substances and how strongly it experiences reward.
Environmental stressors also contribute. Adverse childhood experiences such as abuse, neglect or growing up around substance use raise the risk considerably, as does chronic stress in adulthood.
Social pressures shape both the start and the continuation of substance use. Peer influence, the norms of a social group and the simple availability of drugs or alcohol all play a role.
Personality characteristics such as impulsivity and sensation-seeking predispose some people to substance misuse. Difficulty regulating emotions is a common thread.
Underlying psychiatric problems such as anxiety, depression or bipolar disorder frequently co-occur with addiction. Many people begin using to self-medicate symptoms they have not had treated.
Who Is Most at Risk
Some people carry more risk than others:
- A family history of addiction or mental health conditions
- Age, since dependencies often develop during adolescence or early adulthood
- A history of physical or sexual abuse
- Peer pressure, easy availability, or living in a community with high substance abuse rates
- Impulsivity, sensation-seeking or poor coping skills
Recognising these factors early makes intervention possible before the disorder is entrenched.
Symptoms of Substance Use Disorders
Substance use disorders are marked by recurrent use of drugs or alcohol despite the harm it causes to a person’s physical, mental and social wellbeing.
Common symptoms include:
- Intense cravings for the substance
- Withdrawal symptoms when attempting to quit or cut back
- Tolerance, meaning the need for larger amounts to achieve the same effect
- An inability to control or reduce use despite wanting to
Other signs include neglecting personal or professional responsibilities, taking risks to obtain the substance, and damage to relationships and general functioning.
Recognising these symptoms and seeking help early greatly improves outcomes and prevents further complications.
Physical Symptoms
Physical symptoms vary with the drug involved, the severity of the disorder and the person’s overall health.
Tolerance is one of the clearest. It develops as the body adapts to the drug and requires higher doses for the same effect. Withdrawal follows when use stops or drops sharply, and its severity depends on the substance.
Even medication taken exactly as prescribed can produce tolerance and withdrawal, which is why stopping certain prescriptions needs medical supervision rather than willpower.
Wider physical signs include confusion, episodes of violence, neglect of personal care and secretive behaviour. Deterioration in sleep, weight and general health often follows.
Behavioural Symptoms
Behavioural symptoms are usually what families notice first.
Secrecy is common. People hide their drinking or using, conceal quantities and go to considerable lengths to avoid being found out.
Neglect of appearance often follows, with hygiene and grooming slipping as the substance takes priority.
Responsibilities are the next casualty. Missing work or school, declining academic or work performance and withdrawing from family commitments are all typical.
Diagnosing Substance Use Disorders
Diagnosis involves a comprehensive assessment of a person’s pattern of use and the impact it has across their life. Addiction is a medical condition, and diagnosing it properly requires clinical judgement rather than a checklist alone.
Healthcare providers, whether GPs, psychologists, psychiatrists or counsellors, rely on the criteria in the Diagnostic and Statistical Manual of Mental Disorders. Diagnosis also requires ruling out other explanations for the symptoms, such as medical conditions or other mental health disorders.
Screening and Assessment Tools
Screening tools identify people who may be at risk and indicate whether a fuller assessment is needed.
Several are validated for different age groups, including CRAFFT, CAGE, AUDIT and DALI. Each asks a short series of questions that help a clinician gauge risk quickly.
Comprehensive assessments go further and require specialised skills. They look more closely at the substance history, the psychiatric picture and the social circumstances around the person.
Differential Diagnoses
Several conditions can resemble or accompany a substance use disorder:
- Co-occurring disorders, where depression, anxiety, bipolar disorder or schizophrenia sit alongside the addiction
- Medical conditions, where chronic pain leads to painkiller misuse
- Behavioural disorders, where ADHD or conduct disorder presents with impulsivity and risk-taking
Telling these apart requires a thorough psychiatric assessment, a medical evaluation and a review of the person’s history.
The 11 Diagnostic Criteria at a Glance
The eleven criteria fall into four categories.
| Category | Criteria |
|---|---|
| Impaired control | Using more or for longer than intended; unsuccessful attempts to cut down; cravings or strong urges; spending a lot of time obtaining or recovering from use |
| Social problems | Continued use despite social or relationship problems; giving up or reducing activities that mattered; failing to meet work, study or home obligations |
| Risky use | Using in physically hazardous situations; continuing despite knowing it causes physical or psychological harm |
| Physical dependence | Developing tolerance, needing more for the same effect; withdrawal symptoms when use is reduced or stopped |
Severity is graded by how many criteria a person meets within a twelve-month period. Meeting two or three indicates a mild disorder, four or five moderate, and six or more severe.
Not Sure Where Someone Sits?
A confidential assessment is a conversation rather than a commitment. It is the fastest way to find out whether what you are seeing meets the threshold for a disorder, and what to do about it if it does.
Book a Confidential Assessment
Treating Substance Use Disorders
Treatment is matched to the substance and the severity of the disorder. Where physical dependence is present, treatment starts with medically supervised detox, because withdrawal from alcohol, benzodiazepines and opioids can be dangerous without clinical support.
Treatment runs as a sequence rather than a single event:
- Assessment, which establishes severity, withdrawal risk and any co-occurring psychiatric condition
- Medically supervised detox where physical dependence is present, usually three to seven days
- Inpatient treatment for severe or long-standing disorders, or outpatient treatment where support at home is stable
- Secondary care or sober living, where the recovery is consolidated before going home
- Aftercare and relapse prevention, which is where the long-term outcome is decided
More than half of the people we admit have a co-occurring mental health condition, which is why dual diagnosis care treats the disorder and the psychiatric condition together rather than in sequence.
Treatment by Substance
The substance changes the clinical picture, so the treatment pathway differs:
- Alcohol, where withdrawal carries seizure and delirium risk
- Heroin and opioids, where withdrawal is severe but rarely life-threatening
- Methamphetamine, where psychiatric symptoms often dominate
- Cocaine, where mood and cravings drive relapse
- Cannabis, where sleep and irritability are the main withdrawal features
- Prescription medication, where a supervised taper is usually needed
Substance use disorders are treatable. See our addiction treatment programmes for what care looks like at each stage.
A substance use disorder is a diagnosable medical condition, not a lack of willpower. The signs, how it is diagnosed and how it is treated in South Africa.. Changes team counsellors are here to help you.What Is a Substance Use Disorder? Signs, Symptoms and Treatment
