In short

The signs of substance abuse fall into three groups. Physical: changes in pupils, sleep, appetite and weight, and shakiness or sweating as the substance wears off. Behavioural: secrecy, missing money, dropped plans. Psychological: moods that follow access to the substance, denial, and anxiety that keeps rising.
A full diary does not rule out dependency. Under DSM-5, two or three of 11 symptoms is already a mild substance use disorder, according to the MSD Manual Professional Edition. Someone can meet that bar while still going to work every day.
Family often spots it first. Mood that tracks access to the substance, cash that does not add up, and sleep that changes shape are usually easier to see from outside than from inside it.
Renewed Life Center treats the substance as a symptom of something bigger. A free 20 to 40 minute call, and admission that can be immediate, typically within three days of first contact.

Worried about someone who still seems fine on the outside? Book a free, confidential call with our team. We reply the same day.

Houses climbing a hillside above Fish Hoek, Cape Town, in overcast light

A father makes every school run and closes the big deals at work, but the wine starts earlier each evening, and the bottle empties faster than it used to. A daughter pays her own rent and shows up to every family lunch, and also takes two different prescriptions from two different doctors, because one stopped being enough months ago.

Neither looks like the addiction most people picture. It looks like a busy adult having an ordinary week, which is exactly why a family can miss it, sometimes for years.

What are the physical, behavioural and psychological signs of substance abuse?

The signs usually fall into three groups: what shows in the body, what shows in behaviour, and what shows in mood and thinking. Most people display some of each, not all of one, and a family often notices the behavioural and psychological signs weeks or months before the physical ones become obvious.

Physical signs

Bloodshot eyes, or pupils that are dilated or pinpoint depending on the substance
Sudden changes in weight, appetite or eating habits
Sleep that is too little, too much, or at odd hours
Shakiness, sweating or nausea once the substance wears off
A smell, on breath or clothing, that gets explained away or masked with mints and perfume

Behavioural signs

Secrecy about time, money, or who they have been with
Irritability or defensiveness when the subject comes up, well out of proportion to the question asked
Giving up hobbies or family plans that used to matter, without a real explanation
Using in situations that used to be off limits, such as before work or while driving
Relationships that get smaller, as using quietly takes the place of people

Psychological signs

Mood that tracks access to the substance more closely than the day’s real events
Denial or minimising when someone raises a concern
Anxiety or low mood that gets worse, not better, the longer the using continues
Guilt or shame about the using, alongside a strong pull to keep doing it anyway
A growing sense that the substance is the only thing that works, for sleep, stress or pain

NIDA puts the core test simply: a drug problem is present when a person continues to use drugs even though it’s harming their life. Everything above is a way that harm tends to show up before it reaches a crisis.

Can someone be dependent on drugs or alcohol and still function normally?

Yes. Dependency rarely announces itself with a lost job or a public collapse. Dependency is diagnosed on a scale, and the mild end of it fits comfortably around a job and a family. Someone can meet the mild or moderate bar while working, parenting and paying every bill on time.

Tolerance builds slowly enough that nobody marks the day it changed. A single glass becomes two, then most of a bottle, and the people around that person adjust without noticing they are adjusting: dinner moves later, certain arguments get shorter, one or two subjects quietly stop coming up. By the time a family finally names what is happening, the pattern is often already years old.

A thatched house above a long, empty beach on the Cape Peninsula — Cape Town, South Africa.

What are the 11 DSM-5 criteria for substance use disorder?

The DSM-5 lists eleven possible symptoms in four groups: impaired control, social impairment, risky use and physical dependence. A diagnosis needs two or more from the whole list within a year, not all eleven, and the same list applies whether the substance is alcohol, cocaine, cannabis or a prescription medicine.

The eleven criteria, in four groups

Impaired control

Taking the substance in larger amounts or for longer than planned
Wanting to cut down or stop, and not managing to
Spending a lot of time getting, using or recovering from the substance
Craving, or a strong urge to use

Social impairment

Failing to meet responsibilities at work, school or home
Continuing to use despite it causing problems with people close to you
Giving up activities that used to matter because of the using

Risky use

Using in situations where it is physically hazardous
Continuing to use despite knowing it is making a physical or psychological problem worse

Physical dependence

Tolerance: needing more for the same effect
Withdrawal: physical effects when the substance is stopped

List from the MSD Manual Professional Edition. The American Psychiatric Association defines mild substance use disorder as two to three symptoms from that list of 11, moderate is four to five, and severe is six or more.

Mild substance use disorder2 to 3 symptoms

Severe substance use disorder6 or more

Out of 11 possible symptoms in the DSM-5 framework for substance use disorder.

Source: MSD Manual Professional Edition

What do the signs look like for each substance?

The general list above applies to any substance, but each one leaves its own fingerprints. Cocaine and other stimulants show up differently from opioids, and alcohol differently again from cannabis. The table below is a starting point for a conversation, not a diagnosis.

Common signs by substance
Substance	Signs that often show up
Alcohol	Drinking that starts earlier in the day, rising tolerance, shakiness or sweating the next morning, and gaps in memory of the night before.
Cocaine and other stimulants	Dilated pupils, high energy and talkativeness that fades into a flat, exhausted comedown, weight loss, and, with snorted cocaine, frequent nosebleeds, according to NIDA.
Opioids and prescription pain pills	Pinpoint pupils, drowsiness and constipation, plus prescriptions from more than one doctor, a pattern NIDA calls doctor shopping.
Benzodiazepines and sleeping pills	Drowsiness, a flattened sense of calm, and problems with movement and memory, with a higher risk of slowed breathing when combined with alcohol or opioids, per NIDA’s drug charts.
Cannabis	Bloodshot eyes and a bigger appetite while using. Within days of stopping: irritability, poor sleep and a smaller appetite, signs NIDA lists as cannabis withdrawal.

Locally, alcohol and methamphetamine sit at the top of the list. Of everyone treated in the Western Cape’s specialist services in the first half of 2025, methamphetamine was the primary substance for 30%, alcohol for 26% and cannabis for 24%, out of 1,489 people treated. That is according to SACENDU, the monitoring network run by the South African Medical Research Council. Nationally, alcohol was the primary substance for 24% of admissions in the same period.

What financial and prescription signs point to dependency?

Watch for cash that goes missing without explanation, borrowing that does not add up, and, with medicine, prescriptions from more than one doctor or a habit of running out early. NIDA calls the prescription pattern “doctor shopping”: moving from provider to provider to obtain multiple prescriptions.

A rapid jump in the dose someone says they need, or a string of requests for an early refill, are flagged the same way by prescribers. Both count as signs worth a second look, according to the same NIDA report. Older relatives carry a particular version of this risk: NIDA notes they are at higher risk of accidental misuse of prescription opioids, because they typically have several prescriptions and chronic conditions at once. Money that does not add up is easier to prove than a feeling, and it is often the detail a family remembers first.

What is the difference between drug or alcohol use and dependence?

Occasional use stays under the person’s control: they decide the timing, and work, money and relationships stay steady around it. Dependence flips that order. Use starts to decide the timing, tolerance climbs, and consequences pile up and get explained away. Doctors use the same DSM-5 framework to diagnose that pattern.

Occasional use against dependence
Occasional use	Dependence
Control
The person decides when and how much	Use decides the timing more often than the person does
Tolerance
The same amount has the same effect	More is needed over time for the same effect
Consequences
Work, money and relationships stay steady	Consequences turn up and get explained away
Stopping
A week off is easy and unremarkable	Stopping brings physical or emotional discomfort
Prescriptions
One doctor, one pharmacy, the dose as written	More than one doctor, or refills asked for early

None of these lines is a diagnosis on its own. Together, they are worth a conversation with a professional.

How do the signs differ between teenagers and adults?

Adults tend to hide dependence behind work, marriage and routine, so a career and a tidy house do not rule it out. Teenagers hide it behind school and friendships instead, and the stakes are different: a brain that is still developing is more vulnerable to lasting change from repeated use.

What often shows up first in teenagers

Hanging around with a different group of friends than before
Falling grades or missed classes, where school used to be steady
Losing interest in a favourite sport, hobby or activity
Not caring about appearance the way they used to
Sleep and eating that suddenly look different

List from NIDA’s guide for parents and educators.

Adults tend to hold the outside together for longer, so the signs move to money, prescriptions and the private hours nobody else sees, which is why the earlier sections on this page lean on those details rather than on grades or curfews.

15% of US high school students report having used an illicit or injection drug. Most adults with a substance use disorder started using during their teen or young adult years, per the same CDC data. Adolescence is a period of ongoing brain development, so exposure at this age can have a longer-lasting effect, according to NIDA. That is the case for taking a teenager’s use seriously earlier rather than later, even before anything looks like a crisis.

Why does this happen, and is it just a bad habit?

It is rarely just a habit. For a lot of people, the substance started as an answer: something that quietened anxiety, got them through grief, or helped them sleep after a trauma nobody talks about. Treating the addiction without treating what it was answering is a large part of why relapse is so common. That is the whole argument behind our page on dual diagnosis treatment.

There is also a physical reason stopping is not simply a matter of willpower. With repeated cocaine use, the brain’s reward pathway grows less responsive to ordinary pleasures, while the circuits involved in stress grow more sensitive. That is part of why the days without the drug can feel worse rather than better, according to NIDA’s research summary. Something close to that pattern plays out with most substances people become dependent on. Take the substance away and leave the original problem untouched, and that problem is still waiting the moment sobriety gets hard. It was doing a job, long before anyone noticed the using.

Working out what the substance was doing for someone, and treating that alongside the addiction, is not a job a family can do alone. Dr Ruby Weber heads psychology at the centre. She has worked in the addictions field for more than two decades, with international and South African clients, and has a particular interest in how trauma intersects with dependence.

If a diagnosis has never been the whole picture for your family, book a free, confidential call. Twenty to forty minutes, and we reply the same day.

What are the signs of an overdose, and when do you call 10177 or 112?

Call emergency services immediately if someone is unresponsive, breathing slowly, having a seizure, or turning blue or pale around the lips. Call an ambulance on 10177, or 112 from a mobile.

Signs of an opioid overdose

Unconscious, or cannot be woken up
Slow, shallow breathing, or choking and gurgling sounds
Skin that looks discoloured, especially around the nails or lips
Small, pinpoint pupils that do not react to light

List from the CDC.

Signs of alcohol poisoning

Confusion, stupor, or difficulty staying conscious
Vomiting, or a seizure
Slow or irregular breathing, under eight breaths a minute or long pauses between them
Clammy skin, no gag reflex, or skin turning bluish or very pale

List from the NIAAA. Do not assume sleep is safe, and do not leave the person alone: call for help and stay until it arrives.

Emergency: call 10177, or 112 from a mobile, right now if they are

unresponsive, or breathing slowly after using
having a seizure
confused, very agitated or hallucinating after stopping drinking suddenly
talking about ending their life, or have already tried to

If nobody is in immediate danger but you need to talk it through, the Department of Social Development’s substance abuse helpline runs 24 hours a day and is free. Call 0800 12 13 14, or send an SMS to 32312, a number SADAG publishes. Where the risk is to someone’s life, the Suicide Crisis Helpline is 0800 567 567, day or night.

What should you do once you notice these signs?

Write down exactly what you have seen, get your own advice before you raise it with them, and decide what you are actually asking for. A written record and a clear, small request travel further than a general accusation, and they give you something concrete to say once the moment arrives.

Four steps before you say anything

Write it down

Dates, amounts, specific incidents. Not “always” or “constantly”, detail that somebody could check.
Get advice first

A doctor, a therapist, or a helpline such as SADAG can tell you whether this looks urgent, before you decide how to raise it.
Decide what you are asking for

An assessment is an easier yes than a confession. Aim for one small step. A full promise to change can come later.
Have an option ready

A number to call and a rough idea of what happens next, so a yes can turn into a call the same day.

When you are ready to actually raise it, our guide on how to talk to a loved one about rehab covers what to say, what to avoid, and what to do if the answer is no.

Why do families choose Renewed Life Center when someone still seems fine?

Because a functioning exterior is exactly what dependence hides behind, and here the substance is never treated as the whole story. We start with a free, confidential call. If residential care is the right step, admission can be immediate and typically happens within three days of first contact, with medical detox where clinically indicated and 24-hour nursing supervision.

A resident GP, Dr John Wulz, examines every arrival, and nurses are on duty 24 hours a day. In Lakeside, in Cape Town’s Southern Suburbs, our clinical team works from one plan rather than separate ones for addiction and mental health. Family therapy sessions run alongside treatment, with a video option for relatives abroad.

You pay us directly, so no scheme decides how long you stay: the length of stay follows the clinical picture. For fees, book the free call or write to us, and we send the details in writing the same day.

Book a free, confidential call: 20 to 40 minutes by WhatsApp, video or phone, with no obligation. We reply the same day.

What else do families ask?

No. Occasional use stays under someone’s control, and work, money and relationships stay steady around it. Dependence is what happens when that order flips and use starts setting the terms, which is the comparison set out earlier on this page.

No. A milder pattern already counts under the DSM-5 breakdown above, according to the MSD Manual Professional Edition, and it still deserves a proper conversation rather than a wait-and-see approach.

Denial is common, and it rarely means the family is imagining things. Our guide on talking to a loved one about rehab covers what to say when someone insists they can stop whenever they want.

Yes. Treatment does not need a crisis to work, and waiting for rock bottom mostly just delays help.

Start with people who already understand addiction: family therapy and support at our centre, or the Department of Social Development’s helpline on 0800 12 13 14. Keep an eye on your own sleep and your own life while you wait, because burning out helps nobody.

This article is general information, not medical advice.

Sources

How do you tell if someone who still functions is using drugs or alcohol?

In short