Forensic Science: Fundamentals & Investigations, Chapter 9 1

Introduction Introduction

Forensic toxicology helps determine cause-and-effect relationshipsbetween

o Exposure to a drug or other substance

and o Toxic or lethal effects from that exposure

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ExposureExposure

People can be exposed to toxic substances:

o intentionallyintentionally—by treating illness or relieving pain

o accidentallyaccidentally—by harmful combinations or overdoses

o deliberatelydeliberately—by harming or killing others, or

by suicide

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Poison—>Murder, Accidental Overdoses, and Drug Offences

o Poisoning causes less than ½ of 1% of all homicides

o Accidental drug overdoses are more Accidental drug overdoses are more commoncommon

o Drug offenders

• More than 50% of the federal prison population

• About 20% of the population in state prisons

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Controlled Substances

1. Hallucinogens

2. Narcotics

3. Stimulants

4. Anabolic steroids

5. Depressants

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Controlled Substances —Hallucinogens

o Often derived from plantso Affects the user’s perceptions, thinking, self-awareness,

and emotionso Blood 1-3 days, Urine 3-7 +, hair forever

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Controlled Substances-Narcotics

Urine Test

2-3 Days

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Controlled Substances- Stimulants

o Increases feelings of energy and alertness, Suppresses appetite…Afterwards, depression often results

o Overdose affects include high blood pressure, agitation, confusion, seizures

o Stimulants tend to be highly addictiveo Blood: 5-6 hours or 2-3 days, Urine: 1-7+ days (based on use)

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Controlled Substances- Anabolic Steroids

o A chemical structure similar to testosteroneo Promote cell and tissue growth increasing bone

mass and body muscle. o Popular with weightlifters, bodybuilders, and

other athletes

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Controlled Substances —Depressants

o Affects the central nervous system by increasing a neurotransmitter… causes drowsiness and slowed brain activity

o Relieves anxiety and produces sleepo Side effects include slurred speech and loss of

coordinationo Mixing depressants with alcohol and other drugs

increases potency and health risks

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Controlled Substances—Alcohols

o In what way are alcohols toxic? o How is grain alcohol produced? o What are the classic symptoms of a

hangover? o What is the effect of alcohol on the central

nervous system? o What can chronic alcohol abuse cause?

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Controlled Substances—Bacterial Toxins

o Tetanus (also called Lockjaw)• Produced by the Clostridium tetani bacteria • Causes violent muscle spasms

o Botulism • Produced by Clostridium botulinum—botulism • Paralyzes muscles• Causes irreversible damage to nerve endings• Extremely deadly in very small amounts• Most poisonous biological substance

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Controlled Substances—Pesticides and Heavy Metals

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Controlled Substances—Pesticides and Heavy Metals

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Controlled Substances—Bioterrorism Agents

Ricin o A poisonous protein in the castor bean o Lethal in extremely small amountso Enters the body in various ways:

• inhaled as a mist or a powder • ingested as food or drink• injected into the body

o Causes death within a few hours

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Controlled Substances—Bioterrorism Agents

Anthrax o Bacillus anthracis, which forms endosporeso Spreads to humans from infected animals o Enters the human body through:

• Inhalation; causing breathing problems that usually result in death

• Ingestion; becoming fatal in 25% to 60% of cases • Absorption via the skin; leading to death in about

20% of untreated cases