Addiction & Human Behaviour

1. Addiction & Human Behaviour Session 2

2. Class Outline Review levels of use, DSM IV Criteria, follow-up from last week -“Roots of Addiction” DVD 35 min - routes of administration - structure and function of the brain - neuroanatomy and neurophysiologic action of drugs - tolerance and withdrawal (guest speaker) - dependence

3. Review of Levels of Use Experimental Use - the person tries a drug out of curiosity and may or may not use the drug again. Social/ Recreational Use person seeks out a known drug to experience a known effect, but no pattern has been established Habituation /Regular Use-There is a definite pattern of use. Use doesn’t affective the person’s life in a really negative way.

4. Abuse – continued use despite negative consequences of drug use, e.g., health problems, family, school, work problems, legal problems. • Addiction –The distinction between addiction and abuse has to do with compulsion. The person is psychologically and/or physically dependent on a drug, which is used excessively and the use continues despite the person experiencing serious problems. • The level of drug use depends on amount, frequency, and duration of use as well as a person’s susceptibility to addiction as determined by heredity and environment. • The continued use of a psychoactive drug also affects a person’s vulnerability to develop addiction. All these factors cause alterations in brain chemistry known as allostasis that can affect a person for a few hours, a few days, or even a lifetime. Many of these alterations can be seen with the assistance of new • imaging techniques such as SPECT, CAT, MRI, fMRI, DTI, and PET brain scans. Compulsive behaviors, such as gambling and compulsive eating, also affect brain chemistry.

5. DSM IV Criteria Substance-related disorders are divided into two general categories: 1) substance use disorders and 2) substance-induced disorders. Substance use disorders involve patterns of drug use and are divided into substance dependence and substance abuse. Substance dependence is a pattern of repeated self-administrationthat can result in tolerance, withdrawal, and compulsive drug-taking behavior. Substance abuse is “a maladaptive pattern of substance use leading to clinically significant impairment or distress;” i.e., continued use despite adverse consequences. Substance-induced disorders include conditions that are caused by use of specific substances, e.g., intoxication, withdrawal, certain mental disorders, The World Health Organization (WHO) International Classification of Diseases classifies addictions under Mental and Behavioural Disorders.

7. Routes of Administration Inhaling • Smoking or inhaling delivers the vaporized drug to the lungs where it is rapidly absorbed • through capillaries lining the air sacs (alveoli) of the bronchi (air passages). • Inhaling acts more quickly than any other method of use • 7 to 10 seconds before the drug reaches the brain.

8. Injecting • Substances, such as heroin, cocaine, crystal meth can be injected by three methods: • intravenous (IV, or “slamming”)—directly into the bloodstream by way of a vein (15-30 seconds to the brain) • intramuscular (IM, or “muscling”)—into a muscle mass 3 to 5 minutes) • subcutaneous (“skin popping”)—under the skin (3 to 5 minutes).

9. 3. Mucous Membrane Absorption • Powdered drugs can be snorted into the nose (insufflation) and then absorbed by the capillaries. Mucous membranes can also absorb drugs - • under the tongue (sublingually) or between the gums and cheek (buccally) • effects begin in 3 to 5 minutes.

10. 4. Oral Ingestion • An ingested drug passes through the esophagus and the stomach to the small intestine, where it is absorbed into the capillaries which carry it to the liver to be partly metabolized before being pumped back to the heart and subsequently to the rest of the body. • The effects of drugs taken by mouth are delayed 20 to 30 minutes.

11. 5. Contact Absorption • Drugs can be applied to the skin through saturated adhesive patches (e.g., nicotine, fentanyl) that allow the drug to be passively absorbed for up to seven days. It can take one or two days for therapeutic effects to begin.