Substance use disorder affects a person’s brain and behaviour. They become unable to control their consumption of the drug or medication (note that alcohol and nicotine are also considered ‘drugs’).

Addiction sometimes begins with recreational, social use and becomes more frequent. At other times, it begins with prescription medication. The risk of addiction and how fast it progresses varies by the drug – some cause addiction more quickly than others (for example, painkillers). As time passes, the person needs higher and higher doses to ‘get high,’ and may find that without their drug they feel sad and depressed. Attempts to stop may cause severe cravings and even physical illness. This is called ‘withdrawal.’

Doctors, family, friends, social and support groups, and organised treatment programmes can all play a significant role in helping a person overcome their addiction.

There is a difference between substance abuse and substance dependence, though it isn’t always easy to tell when a person crosses the line from abusing a substance to being addicted to it. Regardless, there are very serious consequences to this kind of behaviour, not just for the person doing it but for those around them as well.

Diagnosing substance use disorder requires a detailed evaluation that may involve assessments by a psychiatrist, a psychologist or a drug counsellor. Blood, urine and other laboratory tests may be requested, but they are not diagnostic as such – rather, they may be used for monitoring a person’s recovery.


Like many other mental health problems, multiple factors contribute to substance use disorder, mainly:

Environment. Family beliefs, social attitudes, peer pressure and exposure may play a role in initial, experimental substance use.

Genetics. Once a person has started consuming the substance, the descent into addiction may be influenced by inherited traits.

Chemical composition. The substances being consumed can be highly or slightly addictive in nature. What a person consumes influences whether and how quickly they become addicted to it.

Brain chemistry. These substances, when consumed, make the brain experience pleasure. It’s the craving for this feeling of pleasure that drives the addiction to consume the substance repeatedly. The changes to the brain may remain long after substance use has stopped.

Mental health issues. While having a mental health problem does not cause substance abuse, people struggling to get back control may try to find relief in the pleasurable sensations delivered by consuming substances.

Signs & Indications

Substance use disorders affect a person’s physical and mental health, behaviour and emotions. By being watchful for signs of an issue, you can ensure your loved one gets professional help to overcome their challenges.

Physical signs may include:

  • Bloodshot eyes, constricted pupils and redness
  • Sudden weight loss and decreased appetite
  • Irregular sleep patterns, whether sleeping too much or too little
  • Changes in complexion, such as acne, marks, or a yellowish tinge
  • Poor hygiene and inattention to cleanliness and personal care
  • Behavioural signs may include:
    • Noticeable sadness, anxiousness or uneasiness
    • Losing confidence in their own abilities
    • Failing to set or follow through on goals, regardless of how big or small
    • Being irritable or having unpredictable mood swings
    • Being secretive and showing anger when questioned even casually
    • Ignoring responsibilities and obligations at work, school or home
    • Poor decision-making – for example, overspending, missing work or school, theft, insubordination


The best way to steer clear of substance use disorder is not to consume these dangerous substances at all, but that’s not always possible, particularly in the matter of prescription medication. As a rule of thumb, make sure you understand the potential effects of medicines that are prescribed for you and take them exactly as per your doctor’s instructions. Always tell your doctor or mental health advisor if you are consuming alcohol or drugs.

Once you are addicted, you are at high risk of having a relapse, even though you may have stayed ‘clean’ for a period of time. If you do start consuming a substance again, there is a very real risk that you will lose control of your consumption.

Here are some of the things you can do to control your substance use:

Stick with the treatment plan. Be alert and monitor your cravings. Don’t discontinue therapy or counselling, or your participation in recovery support groups. Don’t discontinue any medication you may have been prescribed until the course of treatment is over.

Avoid situations that may tempt you. This may involve making major lifestyle changes, and it can be very hard to break away from people and places that are important to you. But your health and recovery are the most important and as peer pressure plays such an important role in substance use, seeking out healthier and safer companionship may be vital to keeping your strong streak going.

Get help immediately if you lapse. Nobody is perfect, and you may at some point start consuming an addictive substance again. If this happens, remember you are not alone. Reach out to your doctor, your mental health professional, family or friends right away so they can support and help you.


Substance use disorders can’t be cured but you can overcome your addiction and remain healthy with individual, group or family therapy; a focus on understanding how addiction works, freeing yourself from dependence and preventing relapse through active monitoring and management; and establishing a level of care that’s customised to your needs, with the participation of your medical and mental health advisors, friends and family.

Detoxification, medical care, psychotherapy, and self-help support groups are all approaches to help people struggling with substance use disorders.

A therapist or counsellor can help you learn to cope with cravings; suggest strategies to avoid relapse and to handle relapses when they occur; talk about other issues you are facing that may drive you to consume harmful substances and help you deal with them; include family members so they can support your recovery better; and address other mental health conditions that may put you at risk.