Substance-Related and Addictive Disorders

Introduction

• The substance-related disorders encompass 10 separate classes of drugs that are not fully distinct:

1. alcohol;

2. caffeine;

3. cannabis;

4. hallucinogens;

5. inhalants;

6. opioids;

7. sedatives, hypnotics, and anxiolytics;

8. stimulants;

9. tobacco;

10. other (or unknown) substances.

• All drugs that are taken in excess have in common direct activation of the brain reward system, which is involved in the reinforcement of behaviors and the production of memories, which yields to normal activities being neglected.

• Instead of achieving reward system activation through adaptive behaviors, drugs of abuse directly activate the reward pathways.

• The pharmacological mechanisms by which each class of drugs produces reward are different, but the drugs typically activate the system and produce feelings of pleasure, often referred to as a ''high."

• Individuals with lower levels of self-control, which may reflect impairments of brain inhibitory mechanisms, may be particularly predisposed to develop substance use disorders, suggesting that the roots of substance use disorders for some persons can be seen in behaviors long before the onset of actual substance use itself.

• Reflecting evidence that gambling behaviors activate reward systems similar to those activated by drugs of abuse and produce some behavioral symptoms appear comparable to those produced by the substance use disorders.

Treatment

World Health Organization. Atlas on substance use (2010): resources for the prevention and treatment of substance use disorders. Geneva: World Health Organization, 2010.