Substance Abuse & Addiction Causes & Effects

No one experiences addiction the same way as someone else. Understanding the signs, symptoms and side effects of addiction is a key component toward starting the recovery journey.

Understanding Addiction

Learn about addiction

Drug addiction or “substance addiction” can occur after a period of repeated drug abuse and is characterized by a damaging pattern of drug use that leads to tremendous problems in the child or teen’s life. One of those problems includes tolerance, a state in which the body and brain have become so reliant upon drugs or alcohol that it leads to symptoms when the drug use is abruptly discontinued or cut way down. Another problem includes withdrawal symptoms, which come about as a person discontinues or cuts down on the drug of abuse and can range from annoyances to life-threatening emergencies.

Any drug that causes euphoria or feeling “high” when used can become a drug of abuse. The common categories of drugs of abuse cause different symptoms and are abused in a variety of ways. The most common classes of drugs of abuse include:

Marijuana (“grass,” “pot,” and “weed”) is the most commonly abused drug in the United States and can be smoked or eaten in food. Abusing pot causes feelings of bliss, memory impairment, impedes coordination, and distorts reality.

Narcotics and opiates, including heroin, prescription painkillers (Vicodin, Oxycodone, Percocet), and opium can be injected, smoked, snorted, or swallowed. Opiate narcotics cause feelings of euphoria, well-being, and relaxation.

Stimulants including cocaine (“coke”), amphetamines (“uppers”), and methamphetamine (“meth”) can be abused in a number of manners: they can be snorted, injected, smoked, or swallowed. The usage of stimulants leads to increased energy and heightened mental acuity.

Hallucinogens and dissociative drugs also known as “psychedelics,” include PCP, LSD, peyote, ecstasy, ketamine, and psilocybin. Hallucinogens and dissociative drugs can be absorbed through the oral mucosa (the tongue), eaten, or smoked, depending on the drug being abuse. These drugs lead to hallucinations and can cause users to hear, see, and feel things that are not there.

Inhalants, which includes solvents (such as gasoline and glues), aerosols (spray paint), gasses (propane, butane), nitrous oxide, and nitrates (“poppers”) are chemicals that lead to intoxication when sniffed or inhaled (a process known as “huffing”). Inhalants lead to light-headedness, dizziness, hallucinations, delusions, euphoria, slurred speech, and impaired coordination.

CNS depressants and downers slow down the central nervous system and the brain, which makes them ideal for treating anxiety and sleep disorders. Common CNS depressants include tranquilizers, barbiturates, benzodiazepines, GHB, and Rohypnol. CNS depressants may be abused by ingestion, snorting, and injection.


Addiction statistics

Worldwide, at least 15.3 million people struggle with drug abuse and addiction. IV drug abuse – drug use that involves injection with a needle into a vein or directly into a muscle – has been reported in 148 countries. Of these, 120 countries report increased amounts of HIV/AIDS infection among this population.

In 2009, approximately 23.5 million people ages 12 and older in the U.S. (or 9.3% of the population) required inpatient treatment for substance abuse or alcoholism. Of these, only about 2.6 million people (or 11.2% of that population) who needed inpatient treatment received it at a specialized treatment center.

Causes and Risk Factors

Causes and risk factors for addiction

There is not one single factor that can determine a child or teen’s risk for developing an addiction to drugs. The causes for addiction involve the influence of a combination of genetic, physical, and environmental risk factors working in tandem. The greater the amount of risk factors a person has, the greater the likelihood that they will develop an addiction.

Genetic: It appears as though our genes combined with environmental influences account for approximately half of a person’s susceptibility to addiction. It has been noted that addiction runs in families; children and teens who have a parent or sibling who have struggled with addiction are more likely to develop an addiction than those without a similar family history.

Physical: Drugs contain chemicals that act on the body’s communication system – the neurotransmitters – and disturb the ways in which these cells usually send, receive, and process information. The longer a person abuses drugs, the more likely that the drugs will cause lasting damage to this system. Long-term drug abuse may lead to the reduction of the neurotransmitters in the brain which leads to a physical dependence upon drugs to function.

Environmental: People who begin to experiment with drugs at an earlier age are at an increased risk for developing drug or alcohol addiction. Other children and teens find the psychoactive effects of certain drugs temporarily relieves unpleasant stresses and overwhelming emotions and rely on drugs to cope with negative life events.

Risk Factors:

  • Lack of parental supervision and involvement
  • Lower socioeconomic status
  • Poor social and life skills
  • Peer pressure
  • Availability of drugs
  • History of aggressive behaviors
  • History of child abuse – physical, emotional, verbal, or sexual

Signs and Symptoms

Signs and symptoms of addiction

Signs and symptoms of drug abuse depend upon the drug abused, frequency of drug use, individual genetic makeup, length of use, co-occurring mental health disorders, and the usage of one or more drugs. The most common symptoms of drugs abused include:


  • Euphoria and relaxation
  • Decreased ability to concentrate and learn
  • Anxiety and panic attacks
  • Psychosis
  • Long-lasting cough
  • Impaired reaction time
  • Distorted sensory perception
  • Impairment in balance, coordination, and memory
  • Increased heart rate and appetite


  • Drowsiness and dizziness
  • Euphoria
  • Heavy feeling in arms and legs
  • Impaired memory
  • Confusion
  • Fainting
  • Respiratory depression and arrested breathing


  • Paranoia
  • Violent, erratic behaviors
  • Psychosis
  • Increased heart rate, body temperature, and blood pressure
  • Increased metabolism and decreased appetite
  • Feelings of exhilaration and increased energy
  • Increased mental acuity
  • Tremors
  • Irritability
  • Anxiety, panic attacks

Hallucinogenic and dissociative drugs:

  • Altered states of perception and total disorientation
  • Insomnia
  • Tremors
  • Impulsive behaviors
  • Nausea, vomiting, diarrhea
  • Panic attacks and increased anxiety
  • Increased heart rate, body temperature, and blood pressure


  • Impaired motor coordination
  • Memory loss
  • Weakness, dizziness and fatigue
  • Brief intoxication
  • Loss of inhibition
  • Nausea and vomiting
  • Headache

CNS Depressants and downers:

  • Confusion and disorientation
  • Slurred speech
  • Impaired coordination
  • Drowsiness and fatigue
  • Decreased respiration and heart rate
  • Depression
  • Impaired memory and judgment
  • Decreased anxiety
  • Overall feelings of relaxation and wellbeing
  • Lowered inhibitions


Effects of addiction

The long-term effects and complications of substance abuse will vary depending upon the type of drug abused, presence of other health-related conditions, frequency of use, individual makeup, and length of drug abuse.

The most common effects of drugs abused are grouped by substance of abuse:


  • Frequent respiratory infections
  • Decline in mental health
  • Increased risks for cancer

Opiates and narcotic drugs:

  • Lowered blood pressure and respiration rate
  • Mood swings
  • Septicemia
  • Collapsed veins and/or abscess at injection site
  • Endocarditis
  • Bloodborne pathogen infection: hepatitis B and C and/or HIV/AIDS
  • Fatal overdose
  • Coma
  • Death


  • Psychosis (chronic or short-term)
  • Malnutrition
  • Insomnia
  • Cardiac and cardiovascular complications
  • Nasal perforation
  • Severe dental problems (“meth mouth”)
  • Stroke
  • Heart attack
  • Seizures

Hallucinogenic and dissociative drugs:

  • Cardiac complications
  • Liver damage
  • Violent, erratic behaviors
  • Breaks from reality – hallucinations and/or delusions
  • Flashbacks
  • Intrusive thoughts
  • Consequences of impulsive, risky behaviors
  • Memory loss


  • Loss of consciousness
  • Memory impairment
  • Damage to cardiovascular and nervous system
  • Delusions
  • Confusion and disorientation
  • Coma
  • Seizures

CNS depressants and downers:

  • Consequences of risk-taking behaviors
  • Permanent changes in the brain
  • Amnesia
  • Decreased respiration rate and blood pressure

Co-Occurring Disorders

Addiction and co-occurring disorders

A great number of children and teens who are addicted to drugs have a co-occurring mental health disorder. The most commonly co-occurring, comorbid disorders include:

  • Depressive disorders
  • Attention-deficit/hyperactivity disorder
  • Anxiety disorders
  • Bipolar disorder
  • Schizophrenia
  • Polysubstance abuse
  • Conduct disorder
  • Oppositional defiant disorder
  • Intermittent explosive disorder
  • Antisocial personality disorder
  • Borderline personality disorder
  • Post-traumatic stress disorder (PTSD)

Withdrawal & Overdose

Effects of Withdrawal and Overdose

If used for an extended period of time, each drug can lead to withdrawal symptoms if a person abruptly stops or reduces the amount used. Withdrawal symptoms range in severity from mild to life-threatening depending on the type of drug. It’s advisable that anyone attempting to stop using drugs seek medical advice before making the attempt. Common effects of withdrawal and overdose include:

Marijuana Withdrawal:

  • Anger and agitation
  • Loss of concentration
  • Headaches
  • Mood swings
  • Depression
  • Insomnia, nightmares, night sweats, and vivid dreams

Opiate Withdrawal:

  • Tremors and spasms
  • Anxiety and panic
  • Nausea, vomiting, diarrhea
  • Rapid heart rate and high blood pressure
  • Irritability, agitation, restlessness
  • Insomnia
  • Chills and sweating
  • Goosebumps
  • Muscle and bone pain
  • Depression
  • Suicidal thoughts and behaviors

Opiate Overdose:

  • Constricted pupils
  • Decreased, erratic, or absent breathing
  • Cyanosis or bluish discoloration of the nail beds and lips
  • Pale, clammy skin
  • Slurred speech
  • Ventricular arrhythmias
  • Slowed, erratic, or stopped heart rate
  • Acute mental status change, decreased response to stimuli
  • Hypotension
  • Coma
  • Death

Stimulant Withdrawal:

  • Drug cravings
  • Insomnia and fatigue
  • Nausea and vomiting
  • Agitation and irritability
  • Depression
  • Tremors and chills
  • Muscle pain
  • Psychosis

Stimulant Overdose:

  • Nausea and vomiting
  • Chills and profuse sweating
  • Tachycardia
  • Erratic breathing
  • Paralysis
  • Heart attack
  • Extreme anxiety, panic, agitation, aggression, restlessness
  • Tightening in chest or chest pain
  • Hyperthermia
  • Hallucinations
  • Paranoia
  • Seizures
  • Stroke
  • Death

Hallucinogenic and Dissociative Withdrawal:

  • Cravings
  • Fatigue
  • Irritability
  • Anhedonia
  • Suicide

Hallucinogenic and Dissociative Overdose:

  • Self-injury or suicide attempts
  • Increased respiration and core temperature
  • Agitation and anxiety
  • Acute psychotic behavior including hallucinations

Inhalant Withdrawal:

  • Syncope
  • Depression
  • Nausea and vomiting
  • Headache
  • Anxiety and irritability
  • Cravings for the drug

Inhalant Overdose:

  • Sudden heart failure
  • Hypoxia
  • Cardiac failure
  • Coma
  • Sudden sniffing death syndrome

CNS Depressants Withdrawal:

  • Loss of appetite
  • Tachycardia
  • Insomnia
  • Anxiety, agitation, and irritability
  • Headache
  • Seizures

CNS Depressants Overdose:

  • Ataxia, weakness and hypotonia
  • Paradoxical agitation
  • Respiratory depression
  • Dizziness
  • Anxiety and agitation
  • Confusion and drowsiness
  • Diplopia and nystagmus
  • Unresponsiveness
  • Hypotension
  • Increased risk of death when combined with alcohol
  • Amnesia
  • Coma