Substance Abuse & Addiction Causes, Signs, Symptoms & Side Effects

Often times the signs of drug addiction can be difficult to identify. One of the most important steps in the recovery journey is understanding the signs, symptoms and side effects of barbiturate addiction.

Understanding Drug Addiction

Learn about drug and substance abuse

Drugs that people abuse provide the user with a certain type of mind-altering intoxication that causes changes in perception, judgment, attention, and physical control. While people abuse substances for many different reasons, the cost to the addict and society at large is high. Some substances of abuse, like cocaine, have declined over the years while others like heroin and methamphetamines have increased.

Nearly all drugs that are abused cause tolerance, meaning that more of the substance is needed to achieve the same high. Many substances that are abused produce substance-specific withdrawal symptoms. Withdrawal from substances of abuse can be as mild as a minor anxiety or as severe as seizures and death. Overdose from some substances of abuse can lead to coma and death. Common drugs that are abused include the following:

Marijuana (also called “weed,” and “pot”) is a drug derived from the plant Cannabis sativa and is the most common drug of abuse in the United States. Marijuana is most often smoked, however there are edible forms of marijuana designed to be eaten. Smoking marijuana does irritate the lungs and marijuana smoke contains more carcinogens than tobacco smoke. While not considered a particularly dangerous drug, marijuana is often called the “gateway drug,” as it tends to be the first illegal drug of abuse. Usage of marijuana can progress into using harder illegal drugs such as cocaine and methamphetamines.

Cocaine (also called “coke,” “crack,” and “blow”) is a substance that is derived from the coco plant of South America. Cocaine comes in a powdered form and a crystal rock form. Depending on which form is used, it produces different highs. Cocaine can be snorted, eaten, smoked, or injected and the effects and high attained depend upon the manner in which the drug is abused. Long and short-term effects of cocaine usage is related to damage to the brain, heart, lungs, and kidneys.

Heroin (also called “smack”) is a potent substance of abuse that can lead to feelings of pleasure and euphoria, drowsiness, and reduced respiration rate. Withdrawal from heroin is often intense as the symptoms of heroin withdrawal can include problems in the gastrointestinal tract, marked confusion and strong sweating. As heroin is typically used by injection, most often with unclean needles, it can lead to greater health problems like damage to the valves of the heart, HIV/AIDS infection, botulism, hepatitis, and tetanus.

Inhalants (usage is commonly referred to as “huffing”) are used by obtaining solvents that create vapors that, when inhaled, cause intoxication. People who huff inhalants breathe these vapors intentionally, either directly from the container, from the bag the substance is in, or from a rag that is soaked in the solvent placed over the nose and mouth. The high obtained by inhalant usage is short-lived but the damage from inhalant abuse can lead to damage in the heart, brain, liver, and kidneys.

Methamphetamines (also called “speed,” “meth,” and “crystal meth”) are powerful stimulants that are rising in popularity on the streets and as a club drug. Methamphetamines are commonly snorted, injected, smoked or eaten. Major side effects of methamphetamine abuse include heart attack, hypertension, paranoia, delusions, loss of teeth (“meth mouth”), strokes, coma, and in some cases death.

Treatment of drug abuse has come a long way. Through years of painstaking research, scientists are learning more about substances of abuse, addition, and ways to prevent and treat drug abuse.


Drug addiction statistics

It’s estimated that worldwide, 5% of the adult population, 230 million people, or one in every twenty adults used an illegal drug in 2010. About 0.6% of the population of the world, or 27 million people, are thought to be problem drug abusers. Cocaine, heroin, and other drugs kill approximately 0.2 million people each year.

Causes and Risk Factors

Causes and risk factors for drug addiction

People use and abuse drugs for a number of reasons. Some are curious about what the drug may do to them while others may succumb to peer pressure. Some people abuse drugs to increase their athletic abilities or intellectual prowess. Still others may abuse drugs to ease other problems in their lives like depression, stress, or anxiety. It’s important to note that drug abuse, which is less about the amount of drugs abused and more to do with the negative consequences of abuse, does not always lead to drug addiction.

There is not one single cause responsible for causing drug addiction. Drug abuse and addiction is generally thought to be a mixture of genetic, environmental, biological, and psychological factors working in tandem to create an atmosphere of abuse.

Many people who later become drug addicts begin to use drugs of abuse at an early age; the late childhood through early teen years. These following factors can work together to cause someone to become a drug addict:

Genetic: Studies have shown there to be a link between people who are born to a parent or are close relative to someone with a drug habit and the development of an addiction later in life. It’s unclear currently as to what precisely causes this.

Biological: Drugs of abuse are designed to release a euphoric high among users by affecting the level of dopamine present in the brain. It’s been suggested by some researchers that those who lack dopamine in the brain may use substances in order to achieve feelings of pleasure to make up for the deficit in dopamine.

Environmental: Young children who grow up in home environments in which life is chaotic are at greater risks for developing risky behaviors, such as substance abuse, later in life. It seems to be especially important if a child is not properly nurtured or does not develop attachments to his or her parents. Other environmental factors that may increase the likelihood of developing a drug addiction include poor scholastic performance, ineffective coping skills, hanging out with peers who abuse drugs, or the feeling that drug abuse is appropriate.

Psychological: Many people who abuse drugs are actually attempting to manage the symptoms of an existing mental illness such as depression or bipolar disorder. To control the symptoms of mental illness, some people use drugs in order to feel more normal.

Signs and Symptoms

Signs and symptoms of drug addiction

Many of the symptoms of drug abuse will depend upon the specific substance that is being abused. Common signs and symptoms of drug abuse may include:


  • Irritability
  • Depression
  • Aggression
  • Violent mood swings
  • Changes in mood
  • Personality changes
  • Feeling hopeless
  • Feeling depressed
  • Suicidal feelings


  • Behavioral changes
  • Stealing or borrowing money
  • Not caring about others
  • Behaving selfishly
  • Declining performance at work or decline in scholastic performance
  • Regularly abusing drugs
  • Lying especially regarding the amount of drugs being abused
  • Not caring about others
  • Abusing drugs while driving or engaging in other dangerous drug abuse
  • Behaving recklessly
  • Frequent problems with the law
  • Mounting legal problems
  • Avoiding friends, family and previously-enjoyed activities in order to get high


  • Looking rundown
  • Frequent hangovers or crashing from bingeing on drugs
  • Health problems with no clear cause
  • Physical problems related to the drug of abuse
  • Tolerance – needing more and more drugs to get the same high
  • Tremors and shakiness
  • Yellowing of the skin or eyes
  • Leg swelling
  • Persistent coughing
  • Increase in abdominal size
  • Fever
  • Pain in the chest
  • Dark colored urine
  • Pain at the site of injection (for IV drug users)
  • Seizures
  • Strokes
  • Heart attack
  • Coma
  • Death


  • Increasing problems with memory
  • Poor concentration
  • Increased confusion
  • Forgetfulness
  • Aggression
  • Violent behaviors
  • Hallucinations
  • Paranoia
  • Delusions
  • Thoughts of harming self or others
  • Cravings for the drug of abuse
  • Psychosis


Effects of cocaine addiction

Long-term effects of substance abuse will vary depending upon the drug that is being abused. Common effects of drug abuse include the following:

  • Unemployment
  • Divorce
  • Domestic abuse
  • Problems in relationships with loved ones
  • Problems holding a job or staying in school
  • Liver disease
  • Hepatitis
  • Problems with the law
  • Trauma
  • Cancer
  • Stroke
  • Heart Attack
  • Seizures
  • Coma
  • Death

Co-Occurring Disorders

Drug addiction and co-occurring disorders

  • ADHD
  • Antisocial personality disorder
  • Anxiety disorders
  • Bipolar disorder
  • Conduct Disorder
  • Depressive disorders
  • Eating disorders
  • Other compulsive behaviors
  • Other substance use and abuse
  • Post-traumatic stress disorder
  • Schizophrenia

Effects of Withdrawal

Effects of withdrawal from drugs

The effects of withdrawing from a substance of abuse are closely related to the drug of abuse and length of time an individual remains using. Withdrawal from a drug should be closely monitored by a medical professional. Some of the most common effects of withdrawal include the following:

  • Intense craving for the drug, even after one has been sober for months
  • Social isolation
  • Inability to concentrate
  • Changes in sleeping patterns
  • Agitation
  • Anxiety
  • Depression
  • Seizures
  • Headaches
  • Feeling restless
  • Tremors and shakiness
  • Sweating
  • Racing pulse
  • Heart arrhythmias
  • Chest tightness
  • Delirium tremens
  • Coma
  • Death