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Module 1 - Forensic Toxicology

Lesson 1 - The Effects of Illegal Drugs upon the Human Body

Psychoactive Drugs and Their Effects upon the CNS

Psychoactive Drugs

Many psychoactive drugs exist; some are legal and others are illegal. Forensic toxicologists analyze psychoactive drugs that are most often illegal. Illegal psychoactive drugs are of several types, each having its unique effects upon the body. Two general categories of psychoactive drugs are depressants and stimulants.

Depressants

Depressants (also called narcotics) are psychoactive drugs that cause drowsiness, sleep, and insensibility. Many depressants prevent the release of neurotransmitters. This stops neuron stimulation, which produces feelings of relaxation. Other depressants mimic neurotransmitters that prevent the feeling of pain and cause a dull, relaxed state of mind. Most depressants are available only through prescriptions from medical doctors. However, one of the most powerful and addictive of all depressants is alcohol—and it is legal. The three most common types of illegal depressants are the opiates, marijuana, and the barbiturates.

Opiates: Drugs are derived from the milky secretions of the poppy flower bulb before it opens. Opiates are thought to mimic the effects of neurotransmitters in the CNS that prevent the feeling of pain, causing a euphoric trance-like state. Frequent use of opiates results in disruption of blood flow, increased risk of infections, and addiction.

The most common types of opiates include morphine, codeine, heroin, Demerol, and methadone.

A Poppy

The death rate for heroin addicts is more than twice the normal rate. The main cause of death of heroin users is overdosing. Heroin addicts do not use the drug for pleasure; they use it to prevent severe withdrawal symptoms.

Beryl Simpson and Molly Connor-Ogorzaly. Economic Botany – Plants in Our World.
Toronto: McGraw-Hill Publishing Company, 1986. (p. 394)

Marijuana: Marijuana is produced primarily from the dried leaves of the Cannabis sativa plant. The active ingredient in marijuana is the chemical, tetrahydrocannabinol (THC). THC is thought to prevent a neuron’s uptake of a common neurotransmitter called acetylcholine, thereby preventing neural stimulation. Marijuana is also classified as a hallucinogen because it alters the users’s normal thoughts and mood. Marijuana intake causes relaxation and gives one a sense of well-being. It also impairs a person’s coordination and visual acuity. Consequently, being high on marijuana severely interferes with one’s ability to operate a vehicle. Heavy use of marijuana has also been linked to various serious lung disorders, addiction, and low sperm counts.

Hashish is a highly addictive form of marijuana derived from the resin secreted from the leaves and flowers of Cannabis sativa plants grown in dry, hot conditions. Hashish causes the same physiological effects as marijuana; however, it does so more quickly and more distinctly.

A Cannabis sativa plant

Barbiturates: Barbiturates (also called downers) are manufactured derivatives of barbituric acid. Twenty-five barbiturates are known, five of which are prescribed legally by physicians. Barbiturates are pills taken orally that suppress the CNS and cause one to feel relaxed and sleepy. Some barbiturates affect the user for long periods and tend to be slow acting; other barbiturates are fast acting. The fast-acting barbiturates tend to be the most popular among illegal abusers. Abuse of barbiturates leads to severe addiction, insomnia, muscle spasms, and convulsions.

The most common types of barbiturates that are illegally abused include amobarbital, pentobarbital, and secobarbital.

Stimulants

Stimulants are psychoactive drugs that increase alertness and metabolism, cause hyperactivity, stimulate sexual arousal, and repress hunger. Some stimulants prevent the breakdown of neurotransmitters causing neurons to fire continuously. Other stimulants mimic the effects of neurotransmitters, resulting in an increase of neural stimulation in the CNS. Most stimulants are available only through prescriptions from medical doctors. The two most common types of illegal stimulants are cocaine and amphetamines.

Cocaine: Cocaine is derived from the leaves of the Erythroxylum coca plant. Cocaine is thought to prevent the breakdown of neurotransmitters in the brain, causing neurons to fire continuously. Cocaine causes the user to feel overly excited, invigorated, and without appetite. Some cocaine users may in engage in uncontrollable, violent behaviour. Abuse of cocaine may result in confusion, paranoid psychosis, insomnia, impotence, addiction, and birth deformities in the babies of women who abused the drug while pregnant.

Crack cocaine is derived from powdered cocaine by dissolving it in a mixture of water and ammonia or water and sodium bicarbonate. The resulting solution is then boiled until a solid substance forms. The solid is removed from the liquid, then dried and broken into small chunks or rocks that are smoked. Crack cocaine produces an immediate high and is more addictive than cocaine. Abusers of crack cocaine run the risk of cardiac arrest, seizures, or lung trauma, and they may exhibit aggressive or paranoid behaviour.

A deadly cocaine overdose can occur quite easily. A lethal dose of cocaine is only 1.2 grams or about ¼ of a teaspoon.

Beryl Simpson and Molly Connor-Ogorzaly, Economic Botany – Plants in Our World.
Toronto: McGraw-Hill Publishing Company, 1986. (p. 398)

Amphetamines: Stimulants that are created from synthetic chemicals and not directly from plants are known as amphetamines. Most amphetamines mimic the affects of certain neurotransmitters in the brain, causing an increase in neuron activity. Amphetamines increase sensory perception and feelings of excitement and can cause violent behaviour, anxiety, confusion, and insomnia. Abuse of amphetamines can cause inflammation of the heart lining, blood vessel damage, skin abscesses, and fetal deformities in babies of women who abused the drug while pregnant.

Common types of amphetamines include Speed, Crystal Meth, and Ecstasy.

The illegal amphetamine, Ecstasy, is considered a type of neurotoxin. A study in non-human primates showed that exposure to Ecstasy for four consecutive days or longer caused damage to neurons in the brain evident six to seven years later.

                                                                                                                                            - National Institute on Drug Abuse

Glossary Term: Euphoric

  • A feeling of being happy or elated

Glossary Term: Derivative

  • A compound derived or obtained from another and containing essential elements of the parent substance

Glossary Term: Metabolism

  • The chemical processes occurring within a living cell or organism that are necessary to maintain life

Glossary Term: Paranoid

  • Exhibiting or characterized by extreme and irrational fear or distrust of others

Glossary Term: Psychosis

  • A severe mental disorder characterized by derangement of personality and loss of contact with reality and causing deterioration of normal social functioning

Glossary Term: Insomnia

  • Chronic inability to fall asleep or remain asleep for adequate lengths of time

Glossary Term: Impotence

  • Incapability of sexual intercourse, often because of an inability to achieve or sustain an erection

Glossary Term: Synthetic

  • Not natural or genuine; artificial or contrived; prepared or made artificially

Glossary Term: Abscess

  • Localized collection of pus in part of the body, formed by tissue disintegration and surrounded by an inflamed area