Warning Signs of Drug Abuse

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Drug abuse continues to be a major concern in the United States. According to the report by Substance Abuse and Mental Health Services Administration (SAMHSA) in 2013:

  • Half of all Americans regularly drink alcohol with about 25% binge-drinking in the last month and heavy drinking reported by 16.5 million people over the age of 12.
  • More than 24.5 million people used an illicit drug in the last month, which is about 1 out of every 10 people.
  • Almost 5% of adults between 18 and 25 years old used prescription drugs in ways other than prescribed.

Knowing the warning signs of abuse creates a better opportunity to address the problem.

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What is Drug Abuse?

Drug abuse is an umbrella term that has different meanings depending on the substance use. Generally, definitions of drug abuse include:

person abusing pills
  • Using an illicit drug like cocaine, heroin, and crystal meth.
  • Taking a prescription medication that is not meant for you or taking your prescription more frequently, at higher doses, or for longer durations that directed.
  • Using a substance for nonmedical reasons or reasons that were not intended like overusing over-the-counter cold medicines to become high.
  • Using a legal substance like alcohol in excess or with high regularity.

Even one use can qualify as drug abuse. Drug abuse usually begins as a willful experience for the person using the substance, and addiction typically is a product of continued drug abuse. Addiction is a persistent urge to obtain and use substances regardless of the negative consequences to the user or others in their lives.

Signs of Drug Abuse


The eyes can provide a great deal of information about drug abuse.

  • Someone under the influence of opioids will have tiny pupils.
  • Someone on a stimulant will have dilated pupils that are so large only a small portion of their iris will be visible.
  • People using marijuana will have eyes that look red and glassy.


Substance abuse can affect the skin in several ways:

  • Someone using any drug intravenously will have bruising and needle marks on their arms or other locations on their body.
  • Someone injecting anabolic steroids can have these marks in areas of large muscles like the upper thigh.
  • People abusing crystal meth can develop sores on their skin from scratching.
  • Crack users may show burn marks on their mouth and fingers.
  • Substances that damage the liver will result in skin that looks yellow.


With substance abuse, weight can either increase or decrease dramatically.

  • People using marijuana may gain weight due to decreased motivation and activity levels.
  • Most notably, stimulants can reduce the appetite to a point where people stop eating completely. Any significant, unintentional weight change can point towards abuse.


Major changes in sleeping habits and energy levels can indicate drug abuse:

  • Someone on a stimulant may spend days awake and constantly active, which will be followed by a crash where they sleep for days.
  • People abusing depressants may seem to be stuck between awake and asleep for long periods or seem to drift in an out of sleep.


Substances change the mood of the person using them, which is one of the primary reasons why someone might begin abusing a drug.

  • Most substances result in a pleasurable, euphoric feeling initially, which encourages further use.
  • After the positive feelings subside, unwanted feelings will present. Increased depression, anxiety, irritability, anger, and irrationality are common among substances abusers.


While influenced by the drug or following the influence, someone may report perceptions that do not match with reality. Examples include hearing voices, seeing people or objects that are not there, delusional thoughts, or other sensory hallucinations. These are referred to as psychotic symptoms. They are often present in mental health issues like schizophrenia, but substance use can trigger similar reactions.

  • They may make statements that signify that they are responding to stimuli that are not present (e.g., talking back to the voices).
  • They might report feeling paranoid that someone is trying to hurt them or listen to their conversations.


Any extreme behaviors that suggest a major shift in functioning can be a warning sign of drug abuse.

  • Obsessive behaviors. Staying up all night to do iron or repeating the same task or phrase over and over in a compulsive manner can be a sign of certain drugs like meth.
  • Missing for long periods of time and establishing new routines with new friends are common behavioral signs.
  • Secretiveness. A shift in communication style to be more guarded can mean the person is trying to hide substance use.
  • Drastic change in beliefs. If someone was previously very religious and focused on their family but now has time for neither, drug abuse might be a factor. Or, someone who was previously not very religious may develop preoccupations with religious content (e.g., quoting or reading the bible persistently).
  • Using measures to conceal. Abusers may try to hide signs of abuse, for example by wearing sunglass inside or long-sleeves in the summer.
  • Paraphernalia. Finding pill bottles, large amounts of money, empty alcohol containers, needles, scales, and other paraphilia hidden around the house are all warning signs.
  • Random injuries and illness. While intoxicated, people are more likely to become injured. If someone is having more “accidents,” drugs could be the culprit.

Video: 8 Telltale Signs of Drug Abuse

Credit: Howcast

Drugs of Abuse Categories

It can be overwhelming to consider the numerous individual substances that can be drugs of abuse. From glues and amphetamines to benzodiazepines and opioids, understanding the substances and the category they belong to will help understand the effects of drugs in those categories. Drug categories include the following:


They cause relaxation and can be tranquilizers, sedatives, and alcohol.

  • These substances are known for their ability to slow down the body, extend reaction times, limit motor coordination, and increase drowsiness.
  • Energy will be low with less motivation and increased sleep.

Opioids/narcotic painkillers

Many prescription painkillers are opioids, which means they are derived from or sharing properties with opium. Heroin, morphine, oxycodone, and hydrocodone fit this category.

  • These can relax and slow the body.
  • They often create confusion and disorientation.
  • Use can result in constipation.
  • People may appear so sleepy they nod off during a conversation.


This category has numerous inclusions like some prescription drugs used for attention-deficit/ hyperactivity disorder (ADHD), such as Ritalin, and illicit substances like cocaine and crystal methamphetamine.

  • They generally speed up the body, making one feel awake, full of motivation, and very energized.
  • Weight loss will be a major warning sign here as a user may spend days awake and active without eating.
  • After use, they may sleep for days to recover.


These are substances that are inhaled to produce a desired feeling that is the result of restricting oxygen to the brain. Usually, inhalants are items found in the home like paints, aerosols, and gasoline.

  • Inhalant abuse will be seen through an appearance of being drunk with slurred speech, diminished motor skills, and disorientation.
  • Prolonged use can result in anger and irritability or a state of indifference.


Examples include LSD and PCP. This class causes distorted perceptions of time and sensory hallucinations.

  • Someone under the influence of a hallucinogen could be seeing, hearing, feeling, tasting, or smelling things that are not present.
  • Pupils will be dilated.
  • After use, the person may report increase mental health symptoms of depression, anxiety, or paranoia.


Marijuana is the most obvious example with hashish included.

  • These substances will trigger confusion and poor memory.
  • Increased heart rate and anxiety are common effects during and following use.
  • Motivation, energy, and activity levels will decrease leading to weight gain.
  • The smell and paraphernalia associated with the substance will indicate use as will products used to reduce the appearance of red eyes.

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Amanda Lautieri is a Senior Web Content Editor at American Addiction Centers and an addiction content expert for DrugAbuse.com. She holds a bachelor's degree and has reviewed thousands of medical articles on substance abuse and addiction.
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