Signs of drug useHow do you tell whether your son or husband is using drugs, and what should you do if you suspect it?

1Is there one sign that confirms drug use?

Many parents look for one decisive sign: the look of the eyes, a smell, or a piece of paper in a pocket. The truth is that most signs of substance use, taken one at a time, have other innocent explanations. What really stands out is the pattern: a group of changes that appear together, differ from the person’s usual self, and last for weeks.

In its guidance for parents, the US National Institute on Drug Abuse (NIDA) warns that adolescence itself is full of mood swings and a desire for privacy, and that telling normal adolescence from the start of a problem depends on how severe and how fast the change is, and whether it comes with other signs. So compare your son with himself a few months ago, not with other people’s children.

Signs also differ by substance and by stage of use: someone who tries a drug once or twice may show no signs at all, while advanced addiction shows in every part of life. This guide covers the general signs they share, and each substance has its own page with its specific signs, linked at the bottom of the page.

2What are the behavioral signs of drug use?

Behavioral changes are usually the first thing a family notices, and they are clearer than physical signs because they touch daily life at home:

• Sudden secrecy: always keeping the room closed, hiding the phone, and being very upset by any ordinary question about where they have been.
• A change of friends: dropping childhood friends and attaching to new people the family does not know and that they do not want to introduce.
• Sharp mood swings: unusual irritability and angry outbursts, or listlessness and indifference, or excessive cheerfulness that does not fit the situation.
• Disturbed sleep: staying up late and sleeping for long stretches in the daytime, or going days with almost no sleep and then sleeping deeply for many hours.
• Loss of interest: giving up sports, hobbies, and family occasions they used to enjoy.
• Lying and justifying: conflicting stories about where they were, when, and what happened to the money, and repeated excuses for absences.
• Sudden, frequent outings: short phone calls followed by leaving quickly, or nights away without a convincing explanation.

These signs alone are not enough to judge, but if three or four of them come together and persist, that is reason enough to open a calm conversation and ask for a specialist’s opinion.

3What physical signs might appear in a person who uses drugs?

Physical signs vary a lot with the type of substance, because each group affects the body differently. The table below summarizes the general picture for each group, with a reminder that the absence of these signs does not rule out use:

Other general physical signs include neglect of personal hygiene and appearance, unexplained weight loss or gain, a runny nose or persistent cough, wounds or bruises they cannot explain, and wearing long sleeves in hot weather. Also notice smells on clothes or in the room, and excessive attempts to cover them with perfumes and incense.

4How does substance use show up at school and work?

School, university, and work are among the clearest mirrors of substance use, because drugs weaken concentration, memory, motivation, and discipline. NIDA guidance advises parents to contact the school when they notice a sudden change in performance:

• A sudden drop in grades after a steady level.
• Frequent absences, or skipping classes and lectures without the family knowing.
• Complaints from teachers about sleeping in class, inattention, or behavior problems.
• Leaving a job, frequent lateness, or conflicts with colleagues and managers.
• Loss of enthusiasm for the future and the goals they used to talk about.

A decline in school performance can also be a sign of depression, anxiety, learning difficulties, or bullying, so do not make it evidence for a verdict. Make it a reason to ask and understand.

5What money and belongings signs point to substance use?

As use continues, the need for money grows, so financial signs appear that parents and spouses notice, and they are often stronger than the physical signs:

For spouses, the signs may show in household spending: sums that vanish from the account, belongings sold, or a sudden inability to meet obligations even though income is unchanged.

6What things might you find at home?

A family may sometimes find worrying items in a room, in clothing, or in a car. We will not describe the paraphernalia in detail here, because it does not help families and could be misused, but it is useful to watch in general for:

• Pills or blister packs of medication not prescribed to them, or a family member’s medication running out at an unexplained speed.
• Items you do not understand the reason for or use of, especially if they are burned at the edges or carefully hidden.
• Small bags or tightly sealed containers in unusual places.
• Many empty cough medicine bottles, or containers of adhesives and solvents with no reason to be there.

7What is not a sign of substance use?

It is important not to turn every behavior into an accusation, because a wrong accusation damages trust and can push a son into isolation. Many of the signs above have other causes that deserve attention in their own right:

If your son takes a medication prescribed by a doctor, some medications can cause drowsiness or changes in appetite. Rather than guessing, this calls for an assessment in which the doctor gathers the whole picture and tells use apart from mental illness and physical problems, or finds that they occur together.

8Does a home test detect drug use accurately?

The home test strips sold in pharmacies give only a preliminary result. The US Food and Drug Administration (FDA) explains that any preliminary positive result must be confirmed by a second test in a laboratory, that some foods, supplements, and medicines can affect the result, and that no test of this kind is one hundred percent accurate.

• False positive: some cold and allergy medicines and others can give a result that looks like stimulants.
• False negative: if the test is done after the substance has cleared from the body, or if the strip does not detect the substance at all, as with many types of synthetic cannabinoids.
• Prescription medications: the strip cannot tell therapeutic use from misuse.
• Effect on the relationship: testing by force or by deception can destroy the trust you will need later to persuade them to get treatment.

So we prefer that testing be part of a complete medical assessment, where the reason is explained to the person and a doctor interprets the result. You will find how long each substance stays in the body on the substance pages, such as how long hashish stays in the body.

9You suspect your son is using: what should you do now?

Suspicion alone is an exhausting stage, but it is also a chance for early intervention before the problem deepens. Here are ordered steps to help you act calmly:

1. 1
   Observe and note

   Record what you notice, with dates, for a short time, without humiliating searches or suffocating surveillance.

2. 2
   Agree at home

   Talk with your partner or whoever shares in raising him, and agree on one position and one message.

3. 3
   Talk at the right time

   When he is sober and calm, using “I’m worried” language rather than “you’re an addict,” and describe what you noticed with specific facts.

4. 4
   Listen, do not judge

   Ask him about the pressures he is under, since use may be an attempt to escape anxiety or sadness.

5. 5
   Ask for an assessment

   Offer him a visit to a specialist to assess the situation, and ask for a family consultation yourself even if he refuses.

If he denies it or refuses, do not give up after the first attempt. Learn the evidence-based approach to conversation and encouragement in our guide on how to persuade a person with addiction to get treatment, and go back to the guide for families of a person with addiction to learn what to avoid and how to protect yourself and the rest of the family.

10Signs of use for each substance

If you suspect a particular substance, these detailed guides cover its specific signs and how to tell it apart from others:

11When do the signs become an emergency?

Some of what you see is a sign of poisoning that needs an ambulance immediately, and it cannot wait for a conversation like other signs of use. These signs call for phoning the ambulance without hesitation, and the details are on the overdose page: