Dr. Sarah KerriganForensic Science

Program DirectorSam Houston State Univers i ty

1

Forensic Toxicology

What do they all have in common?2

Drugs and Poisons

All substances are poisons; there is none which is not a poison. The right dose differentiates a poison…."

Paracelsus (1493-1541)

3

Overview4

What is Forensic Toxicology?

What does a forensic toxicologist do?

Sub-disciplines of forensic toxicology

Forensic toxicologist vs. drug chemist

Types of casework

Examinations and analysis

Testimony and interpretation

Careers in forensic toxicology?

What is a Drug?

A drug can be any chemical agent that affects living processes and has the potential to impair those processes

5

What is forensic toxicology?

The application of toxicology for the purposes of the law

Three main sub-disciplines:

1. Human performance toxicology

2. Postmortem forensic toxicology

3. Forensic drug testing (employment)

6

Forensic Toxicologist vs. Drug Chemist

Drug Chemist

Seized drugs

“Solid dosage”

Forensic Toxicologist

Drugs in biological specimens or other complex material

7

Drug Chemist

Identification of seized drugs (solid dosage analysis) Illicit drugs or substances used in illicit drug

manufacture Clandestine labs (e.g. methamphetamine) Pharmaceutical drugs (diversion i.e. internet) Drug possession, trafficking etc Qualitative (which drug?) and quantitative

(how much?) analysis (sentencing guidelines) Characteristics of drugs (components)

to determine origin Seized drugs rather than drugs in biological

or complex materials

8

Drug Evidence9

Toxicologist

Drugs/poisons in biological specimens – e.g. blood, urine, breath, tissues, stomach contents etc

Living (antemortem) and deceased (postmortem)

Casework applications: DWI, sexual assault, homicide, suicide, accidental, unexplained death etc

Illicit drugs, prescription drugs, OTC drugs, dietary supplements, herbals, plants etc

Qualitative and quantitative analysis in BIOLOGICAL fluids, tissues or other complex samples (matrices)

Interpretation of effects – How does this influence a person?

10

Forensic Toxicology Evidence11

Solid dosage drug analysis12

What is the substance?

Is it controlled?

What schedule is it?Controlled substances Act (I to V)

What is the purity (adulterants)?

How much is there?

Where is it from?

Drug Analysis

Variety of analytical techniques

Variable discriminating power

Categorized accordingly (A, B, C)

Two main spectroscopic techniques used: Gas Chromatography-Mass

Spectrometry (GC-MS)

Fourier Transform Infrared Spectroscopy (FT-IR)

13

Categories of Techniques for Drug Analysis14

Category A Category B Category C

Infrared Spectroscopy Capillary Electrophoresis Color Tests

Mass Spectrometry Gas Chromatography Fluorescence Spectroscopy Nuclear Magnetic Resonance Spectroscopy Ion Mobility Spectrometry Immunoassay

Raman Spectroscopy Liquid Chromatography Melting Point

X-ray Diffractometry Microcrystalline Tests Ultraviolet Spectroscopy

Pharmaceutical Identifiers

Thin Layer Chromatography

Cannabis only:Macroscopic ExaminationMicroscopic Examination

Plant material or extracts of plant material

Chemical (color) tests(Category C)

Microscopic analysis (cystolithic hairs/bear claws)(Category B)

Powders

Color tests

Thin Layer Chromatography

Microcrystalline tests

GC-MS

FTIR

Capillary Electrophoresis(CE)

Color Tests – Marquis Reagent

Above: The Marquis color test to identify heroin. Black tar and powdered heroin are shown.

Color Tests - Sodium Nitroprusside

Above: Sodium nitroprusside color test (Simon’s Reagent) to identify methamphetamine hydrochloride.

Example: Methamphetamine

Marquis Reagent Sodium Nitroprusside

Top Ten List (Seized Drugs)

1. Marijuana2. Methamphetamine3. Cocaine4. No Controlled Substance5. Pseudoephedrine6. Alprazolam7. Hydrocodone8. Oxycodone9. Psilocybin10. 3,4-methylenedioxymethamphetamine (MDMA)

GC-MS

Most widely used technique Forensically defensible Specific Qualitative and quantitative results Labor intensive Many published procedures Gold standard in forensic laboratories Characteristic retention time Characteristic fragmentation Solid dosage AND Toxicology

Step 1: Separation of Components

Step 2: Ionization

Step 3: Separation of Ions

Step 4: Identification25

Characteristic Mass Spectrum26

C8H10N4O2

8x1210x14x142x16

MW 194

Cocaine

Structure Empirical formula C17H21NO4

MW - 303 Fragmentation!

121

m/z 303-121=182

40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 4400

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

110000

m/z-->

Abundance

Scan 443 (4.956 min): coc.D\data.ms82.1

182.1

42.1303.2

272.1122.1 152.1

220.9 341.0 404.7 446.4

CH3N CO2CH3

O

O

Methamphetamine

CH2CHNHCH3

CH3

Empirical formulaC10H15N

(10x12)+(15x1)+(1x14) = MW 149

Fragmentation?

40 60 80 100 120 140 160 180 200 220 240 260 2800

5000100001500020000250003000035000400004500050000550006000065000700007500080000850009000095000

m/z-->

Abundance

Scan 253 (3.710 min): METH-COOL.D\data.ms58.1

91.1

39.1 134.1115.0 207.0 281.0

Methamphetamine Fragmentation

CH2CHNHCH3

CH3

m/z 91m/z 58

40 60 80 100 120 140 160 180 200 220 240 260 2800

5000100001500020000250003000035000400004500050000550006000065000700007500080000850009000095000

m/z-->

Abundance

Scan 253 (3.710 min): METH-COOL.D\data.ms58.1

91.1

39.1 134.1115.0 207.0 281.0

Forensic Toxicology30

What is the substance?

What is it used for?

How do we isolate it from the matrix (blood, urine, brain, liver, drink, tuna sandwich…)?

What kind of effect would it have?

How do we interpret the results (in court)?

Did it contribute to death?

Did it impair performance?

Improve performance?

Other effects?

Postmortem Forensic Toxicology

Death investigation casework

Determination of drugs, alcohol, poisons in postmortem specimens

Are substances present in significant quantities to cause or contribute to death?

Many interpretive issues

31

Postmortem Forensic Toxicology32

Suspected intoxication deaths IVDUs (injection sites) Pill fragments (GI contents) Pulmonary congestion/edema Other observations consistent with drug use Investigative leads or crime scene info Medical records / pharmacy records Are substance(s) present in biological samples

sufficient to cause or contribute to death?

Postmortem Forensic Toxicology33

Homicides Many homicides drug related Drug use may provide motive Individual under the pharmacologic effect of a drug

may influence likelihood of committing or being victim of a homicide

Accidental Death Impairment issues – traffic fatalities Failure of judgment – “I can fly” ADRs, polypharmacy, pharmacogenomics

Postmortem Forensic Toxicology34

Natural Medication compliance and seizures – e.g.

anticonvulsants present and at what level? Medication compliance in mental illness – e.g.

antidepressants present and at what level?Suicides GSW, hanging etc: Drug use / compliance issues

may provide the pathologist with useful information

Specimens35

Blood Vitreous humor Stomach contents Urine Liver Brain Kidney Spleen Lung Muscle Hair Nails

Analysis

Preliminary Screening of samples (antibody-based kits)

Confirmatory analysis

Isolation of drugs/poisons

Instrumental analysis e.g. Gas chromatography-mass spectrometry (GC/MS)

36

Human Performance Toxicology37

What is it? “Behavioral toxicology” How drugs/alcohol influence human performance Routine/non-routine Implications – safety of self/other How we respond to stimuli: mental & physical components Cognitive and psychomotor impairment How these responses differ from the “norm” – i.e. no drug

or no alcohol How much drug, where it goes in the body, what effect does

it have?

38

Which Drugs Can Impair Driving?

1. Any drug that can affect the brain’s perception, collection, processing, storage or critical evaluation processes

2. Any drug that affects communication of the brain’s commands to muscles or organ systems that execute them

For the most part, drugs that affect the central nervous system

Pharmacology

Pharmacokinetics“What the body does to the drug”

pharmakon = drug/poisonkinesis = movement

Absorption Distribution Metabolism Elimination

Pharmacodynamics“What the drug does to the

body”

Receptor interactions Mechanism of action

39

Applications40

Criminal or civil liability

Driving-related tasks (DWI)

Public safety-related issues

Drug-facilitated sexual assault

Child abuse/endangerment

Assault

Homicide

Others

Alcohol & Driving41

Most frequently studied drug and most frequently encountered task – driving while intoxicated (DWI)

Age-old problem 1843 – Railroad employees in NY prohibited from

drinking 1910 – NYC traffic code cited alcohol as a safety

issue 1912 – National Council for Industrial Safety – later

NSC 1914 - National Safety Council (highway safety

interests) – now assumed by National Highway Traffic Safety Administration (NHTSA) – US DOT

Technology – Past to Present42

1900s – Erik Widmark (Sweden) developed protocol to evaluate alcohol-impaired persons

1930s – Rolla Harger (Indiana University) – “Drunkometer” – alcohol in breath

1939 – First DUI legislation in US (Indiana)

1954 – Robert Borkenstein (Indiana University) – “Breathalyzer” – basis for modern BrAC testing

Today – Implied Consent Laws in every state and a per-se level of 0.08 g/dL ethanol in blood

Why the concern?Grand Rapids Study - 1964

43

Accident involvement increased rapidly when BAC was >0.05 g/dL

Drivers with BAC of 0.06 g/dL were twice as likely to cause an accident compared with sober drivers

Drivers with BAC of 0.10 g/dL were 6 times more likely to cause an accident

Drivers with BAC of 0.15 g/dL were 25 times more likely to cause an accident

Study was repeated in 2005 by NHTSA

44

45

Psychophysical Tests

Methods of Directly Examining Mental and/or Physical Impairment

“Divided Attention”

Concentrating on more than one thing at a time (Mental Tasks and Physical Tasks)

Standardized Field Sobriety Tests (SFSTs)48

Developed in 70s with funds from NHTSA Testing and scoring standardized through lab

studies and field validation studies Three of the tests selected to show objective

impairment One-leg stand (OLS) Walk and turn (WAT) Horizontal gaze nystagmus (HGN)

Walk and Turn(Divided Attention Test -

Mental Task and Physical Task)

• Instructions Stage • Walking Stage

Walk and Turn - Test50

Divided attention test in 2 stages: instruction and walking

Instructions given while suspect stands one foot in front of another on a line, maintaining balance

Take 9 heel-to-toe steps along line, make a six-step turning motion, 9 heel-to-toe steps back along line

Impairment measured (scored) by “clues” or the failure to perform the task in accordance with instructions

Walk and Turn – Clues

1. Can’t balance during instructions2. Starts too soon3. Stops while walking4. Doesn’t touch heel-to-toe5. Steps off line6. Uses arms to balance7. Improper turn (or loses balance on turn)8. Wrong number of steps

If the suspect scores two or more clues (points) or cannot perform the test – there is a 68% probability that the BAC is 0.1 g/dL or more

Walk and Turn TestCriterion

2 or more clues indicates BAC above 0.10(68% accurate)

2

One-Leg Stand(Divided Attention Test -

Mental Task and Physical Task)

• Instructions Stage • Balance and Counting Stage

One Leg Stand - Test54

Divided attention test in 2 stages: instruction and balancing while counting

Instructions given while suspect stands with both heels together, arms at side

Raise one leg approx 6 inches off floor and count rapidly from 1001 to 1030

One Leg Stand – 4 Clues55

1. Sways while balancing2. Uses arms for balance3. Hops4. Puts foot down

If the suspect scores two or more clues (points) or cannot perform the test – there is a 65% probability that the BAC is 0.1 g/dL or more

One-Leg Stand TestCriterion

2 or more clues indicates BAC above 0.10(65% accurate)

2

Horizontal Gaze Nystagmus

Involuntary jerking of the eyes occurring asthe eyes gaze to the side.

HGN - Test58

Measures CNS motor pathways by involuntary jerking of eyes

Nystagmus enhanced by alcohol Most sensitive test of the battery of tests Keep head still, follow stimulus (pen) from side to

side Observes for smooth tracking & onset of nystagmus Early onset of nystagmus (closer to center,

smaller angle) greater the BAC

Clue Number 1

Lack of smooth pursuit

Clue Number 2

Distinct and sustained nystagmus at maximum deviation

Clue Number 3

Onset of nystagmus prior to 45 degrees

45o

Horizontal GazeNystagmus Test Criterion

4 or more clues indicates BAC above 0.10(77% accurate)

4

HGN – 3 Clues Per Eye63

1. Lack of smooth pursuit2. Pronounced nystagmus at maximum deviation3. Onset of nystagmus prior to 45 degrees

If the suspect scores four or more clues (points) or cannot perform the test – there is a 77% probability that the BAC is 0.1 g/dL or more

Test may be invalid on individuals with certain medical conditions

Predictive Value of SFSTs at 0.10 g/dL64

68% for WAT(i.e. 68% of those judged impaired by WAT test had BAC 0.1 g/dL or more)

65% for OLS

77% for HGN

When all three tests are used in combination, predictive value was 83.3%

Effect of AlcoholCentral Nervous System

65

Continuum of depression, not discrete effects

Low BAC - apparent stimulant effect (depression of inhibitory processes)

Increasing BAC: judgment, decision-making, perception, reaction time are impaired.

Impairment develops prior to overt signs of intoxication, ataxia, slurring, loss of balance

Mental/physical abilities diminished well before the appearance of a “classic drunk”

Stages of Alcohol Intoxication(Dubowski)

66

Subclinical <0.05%

Euphoria 0.03 - 0.12%

Excitement 0.09 - 0.25%

Confusion 0.18 - 0.30%

Stupor 0.25 - 0.40%

Coma 0.35 - 0.50%

Death >0.45%

Low Dose Alcohol ImpairmentBAC < 0.05

67

Dynamic visual acuity (ability to see detail in moving object)

Divided attention(as low as 0.02g/dL)

Complex reaction time(ability to discriminate among stimuli and respond appropriately as quickly as possible)

Voluntary eye movements(impaired tracking of moving objects)

Moderate Dose Alcohol ImpairmentBAC 0.05 to 0.08

68

Attention Vigilance Tracking Information processing

(some reports indicate impairment above 0.02%) Judgment - decision making, risk-taking,

emergency response Reaction time Psychomotor performance Increased Errors - steering, braking, position,

speed, acceleration

Alcohol Impairment0.08

69

Performance of driving-related tasks decreases at BACs above zero

“It seems that there is no lower threshold level below which impairment does not exist for alcohol” Moskowitz & Robinson, DOT HS 807 280, 1998

“The National Safety Council Committee on Alcohol and Drugs takes the position that a concentration of 80 milligrams of ethanol per 100 milliliters of whole blood (0.08%w/v) in any driver of a motor vehicle is indicative of impairment in his driving performance”,1971.

Why 0.08? – The SCIENCE70

Virtually all drivers, including experienced drinkersare impaired at a BAC of 0.08 (based on a review of nearly 300 scientific studies)

Critical driving tasks are impaired at 0.08 or below

Divided attention 0.02 g/dL Tracking 0.05 g/dL Reaction Time 0.05 g/dL

Drug-Impaired Driving71

Illicit Therapeutic Over-the-counter Herbals or

dietary supplements in some states

Drugs and Driving73

11 million people reported driving after drug use (SAMHSA, 2003)

Drugs (other than alcohol) found in 17.8% fatally injured drivers (NHTSA)

Drugs detected in 10 to 22% of drivers involved in crashes, often in combination with alcohol

Drugs detected in up to 40% of injured drivers requiring medical treatment

Drug use among drivers arrested for motor vehicle offenses in the range 15-50%

Highest rates reported among those arrested for impaired or reckless driving

74

Which Drugs Can Impair Driving?

1. Any drug that can affect the brain’s perception, collection, processing, storage or critical evaluation processes

2. Any drug that affects communication of the brain’s commands to muscles or organ systems that execute them

For the most part, drugs that affect the central nervous system

76

Effects of Drugs on Driving

CoordinationEffects on nerves/muscles -steering, braking, accelerating, manipulation of vehicle

Reaction TimeInsufficient response - reaction

JudgmentCognitive effects, risk reduction, avoidance of potential hazards, anticipation, risk-taking behavior, decreased fear, exhilaration, loss of control

TrackingStaying in lane, maintaining distance

AttentionDivided, not focussed. Time-shared task with high demand for info processing

Perception90% of info processed while driving is visual. Glare resistance, recovery, dark and light adaptation, dynamic visual acuity

77Drug Impaired Driving and Young People: 18% of 21-year olds report drugged driving at least once in the past year

Drug vs. Alcohol DWI78

Statutory schemes vary There are no “per se” drug

concentrations for drugs other than alcohol that are widely accepted by the scientific community

Drug impairment is determined on a case-by-case basis

Inherently more complex (scientifically and legally) than alcohol-related DWI

Drug Impaired Driving - Interpretation

1. Driving characteristics

2. Observed signs, behaviors (officer, EMTs, witnesses, others) and performance on field sobriety tests

3. Toxicology report

Are they consistent?

Is the driver impaired?

Texas Penal Code Section 49.01

"Intoxicated" means not having the normal use of mental or physical faculties by reason of the introduction of … a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body….

79

DRE & Toxicology80

Drug Recognition Expert (DRE)

DRE performs systematic and standardized tests, observes and documents impairment, and renders opinion

Toxicologist

Provides analytical support, tests samples, provides expert opinion on effects of drugs on human performance

Drug Recognition Evaluation

1. Breath alcohol test2. Interview with arresting officer3. Preliminary examination of suspect4. Examination of the eyes5. Divided attention psychophysical tests6. Vital signs7. Dark room examination8. Muscle tone9. Injection sites10. Suspect’s statements & other observations11. Opinion of evaluator (DRE)12. Toxicological examination

Observations82

Drug Impaired Driving - Interpretation

Texas Penal Code Section 49.01

"Intoxicated" means not having the normal use of mental or physical faculties by reason of the introduction of … a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body….

83

84

Our Role: Test, Interpret, Testify

“I knew the suspect was lying because of certain telltale discrepancies between his voice and nonverbal gestures.

Also, his pants were on fire.”

The ToxicologistAs Expert Witness

W H A T I S A N E X P E R T ?

86

Experts Are People Who Know a Great Deal About Very Little,

And Who Go Along Learning More And More About Less And Less

Until They Know Practically

Everything About Nothing

Example: CNS Stimulants87

Central Nervous System (CNS) stimulants E.g. Cocaine, methamphetamine Euphoria Exhilaration Paranoia Impaired motor skills Impaired cognitive functioning Rapid speech, rapid movements, incoherent speech Anxious, excitable Jaw clenching, grinding teeth Muscle tremors, eyelid tremors

CNS Stimulants - DRE88

Pupil size DILATED; reaction to light SLOWED No HGN or VGN Pulse rate ELEVATED Blood pressure ELEVATED Muscle tone rigid Body temperature ELEVATED Injection sites possible

(IV, IN, SM common routes)

89Human Performance Issues

Drive-off-the road accidents

Leaving lane of travel

Speeding

High speed collisions

Erratic or risky driving

Methamphetamine Hysteresis90

Concentration

Effects

ExcitationExhilarationFeel “good”

HyperactiveAgitatedParanoiaConfusionDelusionalIrrationalViolent

FatigueExhaustionConfusionHypersomnolenceDepression

91

92

DUID Case: Hairy Weasel

Driving/Reason for the Stop 30 y male Semi-truck driving erratically Could not maintain lane; officer feared truck may tip

over Traveling southbound in northbound lane Signs/Symptoms/SFSTs While sitting on the curb advised deputy that wheels on

stationary patrol vehicle were moving Driver had seen a weasel run around his truck or it

could have been a hairy little boy about four feet tall Advised of trouble at truck stop where an armed male

and a female had mounted his truck He was driving erratically from side to side to try to

knock off the male, who was brandishing a firearm

DUID Case: Hairy Weasel

Had called animal control to come and get the snakes and weasel from inside his truck

Appeared frantic; Had taken caffeine pills to stay awake OLS – hands and arms in air entire time, poor balance WAT – incorrect number of steps, incorrect turn, nearly fell Good and cooperative attitude Face flushed; rigid muscle tone Unsteady on feet, Eyelid tremors BP 135/90; pulse 112, 130, 106 bpm Pupils 5.5 mm; slow to react Romberg 22s; one inch circular sway Finger to nose - slow and robotic; could not perform testBlood Toxicology Methamphetamine 0.57 mg/L; Amphetamine present

93

94

DUID Case: Zero Motivation

Driving/Reason for the Stop 44 y male Welfare check Officer dispatched to male subject passed out in vehicle

on roadway Vehicle running; truck located at intersection Driver asleep with feet sticking out of drivers side

window in reclined position Truck was in drive, but did not roll due to position on

an inclineSigns/Symptoms/SFSTs Drivers eyes closed but legs were twitching Officer wakes subject; opens eyes, then closes them

again, goes back to sleep

95

Officer places vehicle in park, wakes subject When asked for drivers license states “It’s here somewhere” then

laid back in the seat to sleep Says he has been up for days under the influence of drugs Body was twitching, sweating heavily; No HGN When asked to perform FSTs said “ I don’t think I can do them” OLS – Puts foot down more than three times (cannot perform

test); WAT – Steps offline more than three times (cannot perform test)

When asked if he had taken drugs over the past few days said “Sure partner!”

Blood Toxicology Methamphetamine 0.14 mg/L; Amphetamine,

Ephedrine/Pseudoephedrine, Doxylamine, Dextromethorphan present

DUID Case: Zero Motivation

Careers in Forensic Toxicology

B.S. of M.S. Degree in chemistry, biology or related field (entry level)

Ph.D. in toxicology or related field

Medical Examiner’s Offices

Crime Laboratories

Private Sector Drug Testing Laboratories

96

Questions???97