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Drug Addiction

Drug addiction rarely starts with a loss of control. It usually starts with something that works — a way to manage stress, pain, anxiety, or the pressure of daily life. Over time, what began as a way of coping becomes something the body and mind depend on.

Understanding what drug addiction is, how it develops, and what can help is a useful starting point — whether you are affected yourself or trying to support someone close to you.

What drug addiction is

Drug addiction (sometimes called substance use disorder) is a pattern of drug use that becomes compulsive and difficult to stop, even when it is causing harm. It is not a matter of willpower or moral character. The brain and body adapt to the presence of a drug over time, which is why stopping becomes genuinely difficult, not simply a decision someone has not made yet.

Addiction can develop with illicit drugs, prescription medications, or a combination of substances. The pattern varies depending on the drug, the person, and the circumstances around the use — but the underlying mechanism is similar: the drug becomes central to how someone functions, and life starts to be organised around it.

Types of Drug Addiction

Drug addiction covers a wide range of substances and patterns of use.

Illicit drugs include substances such as cocaine, heroin, ketamine and cannabis. The risks differ significantly between substances. Heroin and other opioids carry a high risk of physical dependence and overdose, while cocaine, ketamine and cannabis can produce powerful psychological patterns of use alongside their own physical and mental health risks.

Dependence can also develop around medication that was originally prescribed for pain, anxiety, sleep or another genuine medical need. Because the recognition questions and withdrawal risks are different, this is covered separately on our prescription drug addiction page.

Polysubstance use means using more than one drug or combining drugs with alcohol. It is common and can increase both immediate and long-term risks. Cocaine and alcohol, for example, are often used together, with each substance making it easier to continue using the other. Where several substances are involved, assessment needs to consider the complete pattern rather than treating each drug in isolation.

How drug addiction develops

Most people who develop a drug addiction did not intend to. Use that begins recreationally, socially, or as a way of managing a difficult period can gradually shift. Tolerance builds — meaning more of the drug is needed to produce the same effect. Stopping becomes uncomfortable, or frightening, or simply feels impossible. Life starts to narrow around the drug.

Several things make addiction more likely to develop:

  • Using drugs to manage emotional pain, trauma, anxiety or depression
  • A family history of addiction or mental health difficulties
  • Starting drug use at a young age, when the brain is still developing
  • High stress environments, or significant life disruption
  • Neurodivergence — people with ADHD, autism or other neurodivergent profiles are disproportionately affected by addiction, often as a form of self-medication

None of these are a cause for blame. They are factors that make it harder to stop — and understanding them is part of how treatment works.

Drug Dependence

Dependence develops when the body or mind adapts to repeated drug use and begins to rely on it. Dependence and addiction are not identical, although they often occur together.

Physical dependence means that reducing or stopping a drug produces withdrawal symptoms. The nature and severity of withdrawal depend on the substance, the amount being used, how long it has been used and whether other substances are involved. Some forms of withdrawal require medical assessment and should not be attempted without appropriate support.

Psychological dependence means feeling compelled to use a drug to manage emotions, stress, anxiety, sleep, social situations or the feeling of being unable to function normally without it. This can be powerful even where withdrawal is not medically dangerous.

Understanding the substances involved and the type of dependence that has developed is important when deciding how someone can stop safely. Read more about drug withdrawal.

Signs of drug addiction

Drug addiction looks different depending on the substance and the person. Some signs are visible; others are easier to hide. Common patterns include:

  • Needing more of the drug to get the same effect
  • Spending a lot of time thinking about the next use, obtaining the drug, or recovering from it
  • Feeling unable to stop or cut down, even after deciding to
  • Continuing to use despite noticeable harm — to health, relationships, work or finances
  • Using alone, or hiding use from others
  • Withdrawal symptoms — physical or psychological — when not using
  • Mood changes: irritability, anxiety or low mood between uses
  • Losing interest in things that used to matter

Not everyone will recognise all of these. Some people are aware that drug use has become a problem but find it hard to name it. Others are surprised when people close to them raise concerns. Both experiences are common.

Health risks of drug addiction

The health risks of drug addiction depend on the substance, the pattern of use, and the person’s underlying health. Some risks are physical; others are psychological; many are both.

Physical risks include damage to the cardiovascular system, liver, kidneys and lungs. Opioids and some prescription drugs carry overdose risk. Ketamine can cause serious and sometimes irreversible bladder damage. Stimulants such as cocaine place significant strain on the heart. Injecting drugs carries additional risks including infection and bloodborne viruses.

Psychological risks include depression, anxiety, paranoia and psychosis — either caused or worsened by drug use. The relationship between drug addiction and mental health is often circular: mental health difficulties can drive drug use, and drug use worsens mental health. Where both are present, both need to be treated.

Social and practical risks include damage to relationships, difficulties at work, financial problems and legal consequences. These often compound over time and can make it harder to seek help.

Drug addiction and mental health

Many people affected by drug addiction are also managing anxiety, depression, trauma, ADHD or other mental health difficulties. Sometimes the drug use came first; sometimes the mental health difficulty did. Often the two are so intertwined it is difficult to separate them.

This is sometimes called dual diagnosis or a co-occurring condition. Where mental health difficulties are present alongside addiction, treatment needs to address both. Treating addiction alone, without addressing what sits underneath it, is less likely to lead to lasting change.

For people with ADHD specifically, the relationship between stimulant use and self-medication is well documented. Our page on ADHD, alcohol and cocaine explores this in more detail.

Drug addiction and family

Drug addiction affects more than the person using. Families often carry significant weight — worry, exhaustion, broken trust, uncertainty about what to do or say. It is common for family members to have been managing the impact of someone else's drug use for months or years before treatment becomes a possibility.

If you are supporting someone affected by drug addiction, our help for families section has information and guidance for people in that position.

Michael Williams

Michael Williams (Mikey) is the Treatment Manager at Abbington House and has been in recovery since 2011. He oversees the day-to-day delivery of care and brings lived experience into every part of the work.