Substance Abuse - Description

Other Names

Chemical dependence
Drug abuse
Drug dependence
Substance use disorder


305, nondependent abuse of drugs

305.0, alcohol abuse

305.1, tobacco use disorder

305.2, cannabis use

305.9, Other mixed or unspecified drug abuse (caffeine intoxication, inhalant abuse, laxative abuse, misuse of drugs NOS, nonprescribed use of drugs or patent medicinals, phencyclidine abuse). NOTE: this is NOT Polysubstance Dependence, which by DSM-IV definition (304.80), pertains to dependence or addiction without a preference for substance to produce a high or intoxication.

ICD9 code 305 includes cases where a person for whom no other diagnosis is possible, comes to medical attention due to the maladaptive effect of a drug on which s/he is not dependent and that s/he has taken on his own initiative to the detriment of his/her health or social functioning. See the Substance Abuse ICD9 (PDF Document 60 KB) file for a detailed list of associated ICD9 codes.


Substance use is defined as the intentional use of any psychoactive or performance-enhancing substance to achieve a non-medical or non-therapeutic effect – this includes use of tobacco products, alcohol, illicit drugs, prescription drugs, and anabolic steroids. Substance use occurs on a continuum from experimental or non-problematic use through substance abuse and dependence as outlined below in the Diagnostic Criteria section. This module will focus upon the use of illicit substances and alcohol. Tobacco Use in Youth and Adolescents and Anabolic Steroids are discussed separately.

Use of illicit substances is pervasive in youth and adolescents in the United States. According to the 2008 Monitoring the Future Study, approximately one-fifth of eighth-grade students, one-third of 10th grade students, and one-half of twelfth grade students report using some form of illicit drug at least once. [Johnston: 2009] When alcohol is included in these statistics, the percentage advances in all age groups to 75-80% of 12th graders.

While many young people experiment with substances without adverse effects, those who progress to substance abuse, or substance use disorder (SUD), often develop problems such as poor peer relationships, depression, anxiety, poor self-esteem, and engagement in high-risk behaviors. Ultimate consequences often include accidents/injury, altercations, school failure, legal difficulty, date rape, acquisition of sexually transmitted infection, and pregnancy. Death rates due to overdose of illicit and non-illicit drugs are rising in the United States. In 2009, of 432 overdose deaths in one state (Utah), the majority involved at least one opioid. Oxycodone was the non-illicit drug most frequently mentioned as a contributing cause of death, followed by methadone, hydrocodone and alprazolam. [Erin: 2009] Adolescents tend to "experiment" with substances, which often means mixing classes of illicit drugs and abusable prescription drugs, and they trend toward pushing higher doses as addiction progresses. Both circumstances put adolescents at high risk for medical sequelae and/or death.


Genetics and Pathophysiology

Family and twin studies suggest a genetic vulnerability to substance abuse initiation, continued use, and propensity for dependence. Recent studies of the genetics of addiction have identified several regions on chromosomes 4, 5, 9-11, and 17 that are likely to contain abuse susceptibility loci for multiple substances including alcohol, cannabis, cocaine, heroin, nicotine, and opioids [Li: 2009] and that likely involve vulnerabilities in the dopamine transporter system (DAT). These findings will become important in determining substance abuse risk for individuals and populations. These genetic studies also allow identification of environmental factors that contribute to substance abuse disorders. Genetic testing for individuals with substance abuse disorders currently has little clinical value and is not recommended.

Three main pathways comprise the human neural reward system. With substance abuse, these pathways are "hijacked" by the rapid release of various neurotransmitters (NTs), which then rapidly release excessive concentrations of dopamine. This massive dopamine release (and/or other involved NTs) results in euphoria and resets the reward center's benchmark for attainment of pleasure.

The physical impact of long-term (and sometimes short-term) substance abuse is extensive. In particular, cardiovascular, renal and hepatic changes are observably affected. However, the long-term impact on neurologic, hematopoetic, immunologic, endocrine, dermatologic, dental, gastrointestinal, and other systems are also important.


The course and outcome of SUD in adolescents is variable. [Simkin: 2002] Recent studies have demonstrated that postponing onset of substance abuse helps to prevent more serious addiction-related issues and progression to dependence disorders. Individuals with substance abuse may reduce or discontinue use in late adolescence or early adulthood. Those with dependence and/or other risk factors are more likely to continue to meet criteria for one or more substance abuse disorders with the associated risks for overdose, accident/injury, difficulties in the educational and vocational settings, and interpersonal problems. Risk factors associated with development or progression of SUD include: [Newcomb: 1995]
  • family history of substance abuse
  • chronic domestic violence and/or physical/emotional abuse
  • sexual abuse
  • parental modeling of substance use, negative communication patterns and lack of anger control in families
  • large family and/or low socioeconomic status
  • association with drug-using peers and gang affiliation
  • initiation of substance use at a young age
  • academic truancy, drop-out, underachievement or failure
  • psychiatric comorbidity (mood disorders, anxiety disorders, ADHD, conduct disorder, eating disorders, suicidality, schizophrenia)
  • in utero exposure to certain substances
  • victimization by bullying

Those with a greater number of risk factors are at higher risk for the onset or persistence/progression of a substance abuse disorder. The severity of the risk factor may also play an important role. NIDA is rigorously studying the impact of exposure to early childhood trauma and the onset of substance abuse.


Emerging data indicates that brain development continues into the third decade [Giedd: 2008] and that alcohol use during this period may have adverse neurodevelopmental consequences. Adolescents with alcohol abuse disorder have poorer memory retrieval and decreased visuospatial functioning than those who do not drink and are at risk for long term selective cognitive deficits. [Brown: 2008] Functional MRI studies have recently shown that adolescent binge drinkers who have been abstinent from alcohol for 33 days have functional neurologic deficits that suggest persistent decreased processing of novel verbal information and a slower learning slope when compared to nondrinking peers. [Schweinsburg: 2010]


According to the 2007 national Youth Risk Behavior Survey of students in grades 9-12: [National: 2009]
  • 44.7% had one drink of alcohol on at least one day in the 30 days prior to survey
  • 26% had five or more drinks in one sitting on at least one day in the 30 days prior to survey
  • 4.1% had at least one drink on school property
  • 38% had used marijuana at least once; 19.7% had used marijuana at least once during the 30 days prior to survey
  • 7.2% had used cocaine at least once
  • 4.4% had used methamphetamine at least once
  • 13.3% had used inhalants at least once
While the numbers of youth engaging in substance abuse are staggering, recent trends show some positive changes: [National: 2009]
  • Rates of cigarette smoking in youth are at their lowest since 1975.
  • Significant decreases have been seen in the rates of alcohol, methamphetamine, cocaine, and hallucinogen use in high school students over the past 5 years.
  • Among 12th graders, perceived harmfulness of illicit substances has increased.

However, abuse of prescription medications such as stimulants, [Setlik: 2009] opioids and tranquilizers [McCabe: 2008] is increasing in all age groups.


Substance abuse and addiction place a significant economic burden upon society. It is estimated that associated health care, crime-related, and other costs due to losses in productivity total more than half a trillion dollars annually in the United States. [National: 2009] Without effective treatment, the presence of a SUD during childhood significantly reduces the overall level of education achieved, as well as family income once adulthood is reached. [Smith: 2010] Without early and effective intervention, the progression of dysfunction and poor health is exponential. Only 1 in 10 adolescents with substance abuse or dependence disorders are identified and, of these, only about 20% receive any services.

In 2006, 26,400 unintentional drug overdose deaths (all ages) occurred in the United States. (Unintentional drug poisoning includes drug overdoses resulting from drug misuse, drug abuse, and taking too much of a drug for medical reasons.) Drug overdose deaths were second only to motor vehicle crash deaths among leading causes of unintentional injury death in 2006. [Morbidity: 2006] It is not uncommon for youth to report the loss of a peer to overdose.

Death rates related to substance abuse are significant. Data from one state (Utah) are representative:
  • in 2007, there were 20.2 drug related deaths and 2.5 drug related suicides per 100,000 [Substance: 2009]
  • statewide deaths (all ages) due to misuse of prescription drugs are increasing [Utah: 2010]
  • in 2009, 310 Utahns died of non-illicit drug overdose deaths, an increase from the 277 who died in 2008
  • prescription drug overdoses are the primary cause of injury deaths, killing more people each year than motor vehicle accidents

Helpful Articles

Sanchez-Samper X, Knight JR.
Drug abuse by adolescents: general considerations.
Pediatr Rev. 2009;30(3):83-92; quiz 93. PubMed abstract

Kokotailo PK.
Alcohol use by youth and adolescents: a pediatric concern.
Pediatrics. 2010;125(5):1078-87. PubMed abstract / Full Text

Morbidity and Mortality Weekly Report.
Increase in Poisoning Deaths Caused by Non-Illicit Drugs --- Utah, 1991--2003.
Centers for Disease Control and Prevention; (2005) Accessed on 5/14/2010.

Substance Abuse Module Authors

Authors: Catherine Jolma, MD - 12/2011
Susan Wiet, MD - 1/2011
Mark Pepper, MS, CPCI - 6/2010
Content Last Updated: 4/2012

The authors listed above are responsible for the overall Substance Abuse Module. Authors contributing to individual pages in the module are listed on those pages.

Page Bibliography

Brown SA, McGue M, Maggs J, Schulenberg J, Hingson R, Swartzwelder S, Martin C, Chung T, Tapert SF, Sher K, Winters KC, Lowman C, Murphy S.
A developmental perspective on alcohol and youths 16 to 20 years of age.
Pediatrics. 2008;121 Suppl 4:S290-310. PubMed abstract / Full Text

Erin Johnson.
Utah Drug Overdose Mortality.
Utah Department of Health; (2009) Accessed on 5/18/2010.

Giedd JN.
The teen brain: insights from neuroimaging.
J Adolesc Health. 2008;42(4):335-43. PubMed abstract

Johnston, L. D., O'Malley, P. M., Bachman, J. G., & Schulenberg, J. E.
Monitoring the Future National Survey on Drug Use, 1975-2008. Volume 1: Secondary School Students.
Bethesda, Md: National Institute on Drug Abuse; 2008: NIH Publication No 09-7402.; (2009) Accessed on 5/1/2010.

Li MD, Burmeister M.
New insights into the genetics of addiction.
Nat Rev Genet. 2009;10(4):225-31. PubMed abstract

McCabe SE, Cranford JA, West BT.
Trends in prescription drug abuse and dependence, co-occurrence with other substance use disorders, and treatment utilization: results from two national surveys.
Addict Behav. 2008;33(10):1297-305. PubMed abstract

Morbidity and Mortality Weekly Report.
Unintentional Drug Poisoning in the United States.
Centers for Disease Control; (2006) Accessed on 5/14/2010.

National Center for Chronic Disease Prevention and Health Promotion.
Alcohol and Drug Use.
Centers for Disease Control and Prevention; (2009) Accessed on 5/5/2010.

National Institute on Drug Abuse.
High School and Youth Trends.
National Institutes of Health; (2009) pdf file is 4124. Accessed on 4/28/2010.

National Institute on Drug Abuse (NIDA).
NIDA InfoFacts: Understanding Drug Abuse and Addiction.
National Institutes of Health, US Department of Health and Human Resources; (2009) Accessed on 5/4/2010.

Newcomb MD.
Identifying high-risk youth: prevalence and patterns of adolescent drug abuse.
NIDA Res Monogr. 1995;156:7-38. PubMed abstract

Schweinsburg AD, McQueeny T, Nagel BJ, Eyler LT, Tapert SF.
A preliminary study of functional magnetic resonance imaging response during verbal encoding among adolescent binge drinkers.
Alcohol. 2010;44(1):111-7. PubMed abstract / Full Text

Setlik J, Bond GR, Ho M.
Adolescent Prescription ADHD Medication Abuse Is Rising Along With Prescriptions for These Medications.
Pediatrics. 2009. PubMed abstract

Simkin DR.
Adolescent substance use disorders and comorbidity.
Pediatr Clin North Am. 2002;49(2):463-77. PubMed abstract

Smith JP, Smith GC.
Long-term economic costs of psychological problems during childhood.
Soc Sci Med. 2010. PubMed abstract

Substance Abuse and Mental Health Services Administration, Office of Applied Studies.
Drug Abuse Warning Network, 2007: Area Profiles of Drug-Related Mortality.
Department of Health and Human Services; (2009) HHS Publication No. SMA 09-4407, DAWN Series D-31. Rockville, MD. Accessed on 5/14/2010.

Utah Department of Health.
Rx drug deaths back on the rise in Utah.
Utah Department of Health; (2010) Accessed on 5/14/2010.