The Hijacked Brain

Dennis M. Shaughnessy, MD ABAMThe Springboard Center

200 Corporate DriveMidland, TX 79705

432-620-0255www.springboardcenter.org

Addiction is not a character flaw or a sign of weakness, but a disease similar to other psychiatric diseases.

Its cause can be better understood by explaining the brains function during the addiction process.

ASAMAmerican Society of Addiction Medicine

Public Policy Statement: Short Definition of Addiction

Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry. Dysfunction in these circuits leads to a characteristic biological, psychological, social and spiritual manifestations. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors.

Addiction is characterized by inability to consistently abstain, impairment in behavioral control, craving, diminished recognition of significant problems with one’s behaviors and interpersonal relationships, and a dysfunctional emotional response. Like other chronic diseases, addiction often involves cycles of relapse and remission. Without treatment or engagement in recovery activities, addiction is progressive and can result in disability or premature death.

Plasticity of brain function The fact that the brain changes permanently in regards to both internal and external stimulation.

Psychopharmacology and Plasticity are beginning to provide an explanation of two characteristics associated with addiction:

Tolerance & Withdrawal

At the very center of this model is the idea of the

Pleasure Center (Olds & Milner, 1954 )

Using the brain stimulation paradigm, they came to the

following conclusions:

• Electrical Stimulation of the brain could be experienced as pleasurable or rewarding

• An area known as the Nucleus Accumbens played a major role in this response

Drugs Work In The Midbrain

NOT in the Cortex

and how do we know this? …

Midbrain• Survival• Unconscio

us• No free

will

James Olds, PhD (1922 - 1976)

• Discovery of the reward system in the midbrain

• Mice will self-administer electric currents to the Ventral Tegmental Area of the midbrain

• They prefer the electrical stimulation over other survival rewards such as food

Subsequent experiments have demonstrated animals will take drugs or choose electrical stimulation of the brain at the expense of normal activities (i.e. eating, sleeping) and that they come to prefer an environment that they associate with the drug

These experiments led to the formulation of the idea of a brain “Pleasure Center”

This gives new meaning to the words “To Die for”

Much work subsequent to this has established that a class of neurotransmitters, known as the catecholamines, which includes Norepinephrine, Epinephrine, and Dopamine, seemed to be involved.

Of particular interest, is the neurotransmitter, Dopamine, whose activation in the area of the brain known as the Nucleus Accumbens, appears to be a common denominator in many drugs of abuse.

Addiction Neurochemical #1

Dopamine• All drugs of abuse and potential

compulsive behaviors release Dopamine

• Dopamine is the first chemical of a pleasurable experience and is at the heart of all reinforcing experiences

• DA is the neurochemical of salience (it signals survival importance)

• DA signals reward prediction error

• Tells the brain “this is ‘better than expected’”

Addiction Neurochemical #2

Glutamate• The most abundant neurochemical in

the brain

• Critical in memory formation & consolidation

• All drugs of abuse and many addicting behaviors effect Glutamate which preserves drug memories and creates drug cues

• And … glutamate is the neurochemical of “motivation” (it initiates drug seeking)

DOPAMINE (DA) GLUTAMATE (Glu)

• All drugs of abuse and potential compulsive behaviors EFFECT Glu

• Drug memories

• Drug seeking

• “OK, I’ll remember”

• “Fine, go and get it”

• Caudal (toward the tail) projections:

• PFC > NA

• All drugs of abuse and potential compulsive behaviors INCREASE DA

• Reward salience

• “this is important!”

• “I really want this!”

• Rostral (toward the nose) projections:

• PFC < NA < VTA

Nucleus Accumbens

The release of Dopamine in this area seems to be

related to the experience of intense pleasure

• Nucleus Accumbens

• Ventral Tegmental Area (VTA)

• Prefrontal lobe

• Limbic System

The Major Brain Areas Included in Addiction Are:

Studies have begun to compare how different activities affect the level of stimulation in this system with some very interesting results.

Level of Intensity (from greatest to least)

1. Addictive Drugs2. Sexual Activity3. Eating4. Exercise5. Mediation, Spirituality, Deep thought, Art,

Music, Nature, Socialization

Phineas Gage (1823 – 1860)

• Railroad construction foreman in Vermont

• Tamping rod driven through his skull by explosion

• Damage to Left Frontal Lobe and profound personality change

• “Gage was no longer Gage”

Ventral Tegmental Area – When stimulated, sends a signal (release of

Dopamine) to the Nucleus Accumbens, and then, through the process of reuptake, ends this signal

– Also is involved in what has become known, as an Anticipatory signal• If this anticipation can’t

be fulfilled, it might be replaced with another behavior

• It is believed many forms of addiction begin here!

Prefrontal Lobe– Willed actions are associated with this area, in

contrast to “routine” or “automatic” tasks

– Mediate or inhibit these relatively automatic or “fixed action patterns”, giving these behaviors certain flexibility and relative independence from the environment

– Damage to this area can lead to• Disinhibited behavior• Perseveration• Failure to assess consequences of ones actions• Apathy• Poor self-monitoring

The Frontal Cortex

• The “Human” Brain• Processes judgment,

executive decision making,

• Conscious emotions• Confers emotional

meaning onto objects in the world

• Seat of the Self and Personality

• “Love, Morality, Decency, Responsibility, Spirituality”

Executive Functioning• Abstract thinking• Motivation for goal-directed activity• Planning and problem-solving• Attention to tasks• Inhibition of impulsive responses• Weighing consequences of future actions• Flexibility of responses (rule shifting)• Reflective decision-making

Gives us the capacity to use past experience and knowledge to make sense of our current behavior

Failure of Executive Functioning

• Premature, unduly risky, poorly conceived actions

• Urgency• Sensation seeking• Expressed emotions inappropriate to the

situation• Deficits in attention, lack of perseverance• Rapid responses without reflection or

premeditation• Insensitivity to consequences• Impulsive choice (increased delay

discounting)

Limbic System

–AmygdalaPrimitive emotional responses (i.e. anger, surprise, fear, novelty)

• We recall how well we feel when we satisfy the addiction (i.e. good feelings around Christmas, Birthday, Hanukah, many years later)

• This at times overwhelms our logic!

• This explains why stimuli are associated with addiction (i.e. a bar, friends, neighborhood, drug paraphernalia)

–Hippocampus• Long-Term Potentiation (LTP): Physical process in

which memories are formed- relies on the neurotransmitter Glutamate

In addition to causing the experience of pleasure, the Dopamine system by virtue of its’ connections with the frontal lobe, can help explain some of the behavioral results of long-term substance abuse

It has been suggested that the Mesocortical Dopamine System serves to take the prefrontal cortex “off line” during stressful events so that faster, more automatic or instinctive processes are mediated by the limbic system

Putting It All Together

Acute depression of prefrontal lobe activity due to excessive inhibitory mesocortical dopaminergic neurotransmission evoked by drugs is increasingly accompanied over time by sensitization of dopaminergic transmission and perhaps chronic neurotoxic drug or dopamine actions on the frontal lobes, should significantly reduce the inhibitory control exerted by prefrontal cortical areas over posterior cortical and subcortical systems mediating reinforcement and automatization of behavior (Tiffany, 1990).

Leads to impaired control over drug use and behavior in general

Newer theories of addiction suggest that over time, humans have either discovered or manufactured substances that hijack this system, creating addiction

In addiction, the drug hijacks the survival hierarchy and is so close to actual survival that it is indistinguishable from actual survival

New #1 DRUG

2. EAT3. KILL4. SEX