Born to Be Bad? the Biological Basis of Criminal Behavior

Born to Be Bad? The Biological Basis of Criminal Behavior

Clare Malone, Harvard University What is “criminal behavior”?

Isadore Posoff. Work Projects Administration Federal Art Project, Pennsylvania. Two Types of Aggressive Behavior

Instrumental Aggression: A lack of emotional sensitivity

Reactive Aggression: An excess of emotional sensitivity Psychopathy

A disorder associated with lack of empathy and remorse

80% of psychopathic criminals will commit another violent crime within 3 years of release

By Paul Goyette (http://www.ﬂickr.com/photos/pgoyette/ By Evan-Amos (Own work) [Public domain], via Wikimedia 168076182/) [CC-BY-SA-2.0 (http://creativecommons.org/ Commons licenses/by-sa/2.0)], via Wikimedia Commons Case 1: Brian Dugan

Brian Dugan, convicted rapist and serial killer, murdered three women, including two young girls

Example of instrumental aggression

Mug shot of Brian Dugan released by Dupage County Sheriff’s Dept. Case 2: Bradley Waldroup

Murdered his ex-wife’s friend and attempted to murder his ex- wife in an extremely violent fashion after a domestic dispute

Example of reactive aggression

By Yumi Kimura from Yokohama, JAPAN [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons Roadmap for the evening

1. Regions of the brain involved in violent behavior

2. The role of neurotransmitters

3. Genetic contributions 1. Regions of the brain involved in violent behavior

By Mysid [Public domain], via Wikimedia Commons Phrenology

Buchanan's Journal of Man, November 1887 Flickr- Double M licensed by creative commons Phineas Gage

[Public domain], via Wikimedia Commons Phineas Gage

John M. Harlow, M.D. ([1]) [Public domain], via Wikimedia Commons You can see Phineas Gage’s skull at the Warren Anatomical Museum at Harvard Medical School

Jeremy Mulrich—Flickr via Creative Commons The Brain

Parietal

Frontal Occipital

Temporal

By Mysid [Public domain], via Wikimedia Commons Functional Specialization

Different areas of the brain are specialized for different functions

• Frontal: executive functions

• Parietal: integrating sensory information

• Temporal: visual memories/language

• Occipital: primary visual cortex

By Mysid [Public domain], via Wikimedia Commons Hypothesis:

If different locations in the brain have different functions, activity in regions of the brain may be different in violent people Questions? Hypothesis:

If different locations in the brain have different functions, activity in regions of the brain may be different in violent people Functional Imaging of the Brain

PET—measures glucose fMRI—measures oxygen

By Unknown photographer [Public domain], via Wikimedia Commons

By John Graner, Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA [Public domain], via Wikimedia Commons Positron Emmission Tomography (PET)

Radio-labeled Glucose

The areas that have the highest signal have taken up the most glucose and are thought to be the most active Positron Emmission Tomography (PET)

Radio-labeled Glucose

The areas that have the highest signal have taken up the most glucose and are thought to be the most active By Unknown photographer [Public domain], via Wikimedia Commons Do violent offenders pleading not guilty by reason of insanity have different brain glucose consumption?

22 murderers pleading not guilty 22 non-murderer controls– age by reason of insanity and gender matched Murderers had lower glucose uptake in the pre-frontal cortex compared to controls

Pre-frontal cortex

Murderer Control

(Raine et al 1994) Functional MRI

Active area

Active areas of the brain need more oxygen

By John Graner, Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA [Public domain], via Wikimedia Commons Are psychopathic brains different?

Criminal Non-criminal psychopaths Non-psychopaths Are psychopathic brains different?

positive neutral negative

Skull By Patrick J. Lynch, medical illustrator (Patrick J. Photo by dvs ﬂickr [creative commons licenses] Lynch, medical illustrator) [CC-BY-2.5 (http:// creativecommons.org/licenses/by/2.5)], via Wikimedia Commons

Different regions of the brain are active in psychopathic criminals

Negative Images Positive Images

Blue=higher in psychopaths Red= higher in normal controls Green= active in both

(Muller et al. 2003) The frontal lobe and the limbic system appear to be important

Frontal Lobe Limbic System

The observed differences in activation of these regions vary between studies Limitations to brain imaging studies

(Bennet et al 2010) What other limitations exist?

• Small Study Sizes

• Control Groups

• Selection of Aggressive Groups

• Comparison between extreme groups Summary

Functional Specialization Imaging Studies

Limitations to these Studies Questions? Case 1: Brian Dugan

• Confessed to killing a 10-year-old • Already serving 2 life sentences • 38 on the psychopathy checklist revised (PCL-R) • Results of an fMRI scan used by the defense

Mug shot of Brian Dugan released by Dupage County Sheriff’s Dept. Do you think that the jury was swayed by the use of fMRI?

Brian Dugan was given the death penalty (although this was converted to a life sentence when Illinois outlawed the death penalty in 2011). How could evidence of a biomechanism impact sentencing of psychopaths?

16 13.93 14 12.83 12 9.336 10 8 6 4 Years of Sentence 2 0 Average Psychopath Pyschopath with Biological Explanation

(Adapted from Aspinwall et. al 2012) 2. The role of neurotransmitters in criminal behavior

By Dhp1080, svg adaptation by Actam (Image:Neuron.svg) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons Neurons are the basic unit of the brain

Receives signals Sends signals to from other other neurons neurons

Neurotransmitters Receptors

Stimulus

Signaling End Receiving End Neurotransmitters are chemicals that transmit signals from neurons

Neurotransmitters

Examples: Serotonin, Dopamine, Epinephrine, Norepinephrine This signal ends when neurotransmitters are taken back into the neuron and degraded

Neurotransmitters

Re-uptake Transporters Neurotransmitter levels can affect behavior

Serotonin

Inhibiting the re-uptake of serotonin can be an effective therapy in depression Dopamine Dysregulation Syndrome

Some people treated for Parkinson’s disease become addicted to gambling

Wikimedia commons Hypothesis: Altered serotonin levels lead to aggressive behavior

No consistent way to test serotonin levels Questions? 3. Genetic contributions to violent behavior Behavioral Genetics

The study of how genes inﬂuence behavior

By KF [Public domain], via Wikimedia Commons A review of human genetics

Each person has 46 chromosomes in each cell

By Andreas Bolzer, Gregor Kreth, Irina Solovei, Daniela Koehler, Kaan Saracoglu, Christine Fauth, Stefan Müller, Roland Eils, Christoph Cremer, Michael R. Speicher, Thomas Cremer [CC-BY-2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons Each chromosomes contain hundreds of genes Each gene codes for a speciﬁc protein

By National Human Genome Research Institute (http://www.genome.gov/Images/EdKit/bio2b_large.gif) [Public domain], via Wikimedia Commons Alleles are alternative forms of the same gene

Example: There are three alleles for blood type, A, B, and O

My Mom My Dad

A O B O

O O A O

Me My Sister Genes and environment interact

“Nature” “Nurture”

Bonjour!

Blood Type Language you speak

Height

Most behavioral traits are a result of this interaction

Photo by Fir0002/Flagstaffotos Heritability is the proportion of observed variance attributable to genetic variance

Shared Environment

Heritability Non-Shared Environment

Genetic Genetic Heritability is not the same as inheritance

Inheritance Heritability

Individual Population

Photo by James Cridland--ﬂickr How do we know that some behavior is heritable?

Twin Studies! Twin Studies

Identical Twins Fraternal Twins 100% Shared Genetic Material ~50% Shared Genetic Material

If one twin has a trait, how likely is the other twin to have the same trait?

If the trait is heritable, identical twins will share the trait more often than fraternal twins Adoption Studies

Biological Parents Adopted Parents (Genetic) (Environment)

How do the traits of biological and adoptive parents impact the child’s traits? An analysis of 51 twin and adoption studies on aggression

Genetic

43% 41% Shared Environment Non-Shared Environment 16%

(adapted from Rhee and Waldman et al. 2002) The psychopathic trait also appears to be heritable as well

Genetic 37% 63% Non-Shared Environment

But remember, many psychopaths are not violent

(adapted from Larsson et al. 2006) Questions? How do we ﬁnd what genes are causing this heritability?

1) Genome Wide Association Study (unbiased)

2) Candidate Gene Approach (biased) Identifying genes that are involved in complex traits

People with trait People without trait Genome Wide Association Studies

Look at many sites at once

By M. Kamran Ikram et al [CC-BY-2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons Unbiased approaches have yielded nothing

(Tielbeek et. al. 2012) Why was the unbiased approach unsuccessful?

• Gene and environment interaction

• Effect size

• Genetically complex

• Deﬁnition of anti-social behavior Early Candidate Gene Approaches

The Y Chromosome!

Males are 9 times more likely to commit murder than females

In 1965, a study reported that more inmates than average had an extra Y chromosome XYY syndrome “Super-males”

When population-wide studies were done, no correlation was found between an extra Y chromosome and aggression

By User:The cat ([1]) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons Males in a large Dutch family demonstrated borderline mental retardation and a tendency towards aggressive outbursts

female male

(Adapted from Brunner et al. 1993) Brunner Syndrome

C T C

C C T C C C T C C T T T C T

C T C

Narrowed the region of interest to an area on the X-chromosome that contains MAOA, and found a C to T mutation in affected males and carrier females (Adapted from Brunner et al. 1993) MAOA Monoamine Oxidase A is responsible for degrading neurotransmitters including serotonin

MAOA Variants of the MAOA gene

MAOA MAOA-H

Regulatory region

MAOA MAOA-L

MAOA-H thought to be expressed at higher levels than MAOA-L (this has never been demonstrated in the brain) Hypothesis: Men with the MAOA-L allele are more likely to commit violent crimes

Gene, Environment Percent convicted of violent crimes

Low MAOA, no maltreatment 3

High MAOA, no maltreatment 7

Low MAOA, maltreatment 32

High MAOA, maltreatment 20

Slight increase in violent crimes only among those that had been maltreated as children

(Adapted from Caspi et al. 2002) Does MAOA-L predispose to violence?

• Difﬁcult to replicate

• No difference in general population

• 35% of males have the MAOA-L variant

• Correlative not causative studies Correlation is not Causation

By Acidburn24m at en.wikipedia [Public domain], from Wikimedia Commons Questions? Other “candidate” genes

COMT (Catechol-O-Methyl-Transferase)

(dopamine, epinephrine, norepinephrine)

COMT

Some studies connect a lower activity allele of COMT with increased violence in schizophrenic patients, others have found no correlation Other “candidate” genes

SLC6A4- The serotonin transporter

SLC6A4 “long allele” SLC6A4 “short allele” A study of the studies!

185 studies on violence and aggression 31 different candidate genes 60000 individuals

No signiﬁcant associations found

(Vassos et al. 2013) The genome wide association study failed to ﬁnd any of these candidate genes

• If these genes are actually associated it is likely only in certain environmental contexts

• Genetics is not destiny

(Tielbeek et. al. 2012) Case 2: Bradley Waldroup

Bradley Waldroup was charged with ﬁrst degree murder and attempted ﬁrst degree murder which carries the death penalty Do you think the jury was swayed by the MAOA-L argument?

The jury returned a verdict of voluntary manslaughter and attempted second-degree murder. He was sentenced to 32 years in prison, the maximum that these charges carry. Summary

• Functional Imaging

• Neurotransmitter hypothesis

• Genome wide association studies

MAOA • Candidate gene approaches

Regulatory region

MAOA This is a biology in its infancy

By BVU-121 - Robert [FAL], via Wikimedia Commons Leonardo da Vinci [Public domain], via Wikimedia Commons Thank you! SITN would like to acknowledge the following organizations for their generous support.

Harvard Medical School Office of Communications and External Relations Division of Medical Sciences

The Harvard Graduate School of Arts and Sciences (GSAS)

The Harvard Graduate Student Council (GSC)

The Harvard Biomedical Graduate Students Organization (BGSO)

The Harvard/MIT COOP Questions? Behavioral traits are not inherited , but are often heritable

Inherited Heritable

Blood Type The Danish Twin Study

Twins in Denmark have been registered since 1870, as have criminals

Monozygotic Twins (MZ) Dizygotic Twins (DZ) 100% Shared Genetic Material ~50% Shared Genetic Material Shared Environment Shared Environment

Concordance: Structural Imaging of the Brain

CT MRI By Mikael Häggström) [Public domain], via Wikimedia Commons Some studies have found differences, but they are not conclusive • Biological vulnerability to social causes of crime • http://books.google.com/books? hl=en&lr=&id=C3Gi1ob0W4oC&oi=fnd&p g=PA53&dq=biology+of +crime&ots=oTKwwFhu0c&sig=8ynsJYpuJ mPw6vIXz1opBFYWAAw#v=onepage&q=b iology%20of%20crime&f=false Alleles are a number of alternative forms of the same gene at a single genetic locus

Example: There are three alleles for human blood type, A, B, and O

AA AO AB BB BO OO

Each individual has two copies of this gene, so they have at most 2 alleles Alleles are alternative forms of the same gene

Example: There are three alleles for blood type, A, B, and O

My Mom My Dad

A O B O

O O

Me Alleles are alternative forms of the same gene

Example: There are three alleles for blood type, A, B, and O

My Mom My Dad

A O B O

A O

My Sister