Presentation on theme: "The Hijacked Brain Dennis M. Shaughnessy, MD ABAM The Springboard Center 200 Corporate Drive Midland, TX 79705 432-620-0255 www.springboardcenter.org."— Presentation transcript:
1 The Hijacked BrainDennis M. Shaughnessy, MD ABAM The Springboard Center 200 Corporate Drive Midland, TX
2 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.
3 ASAM American Society of Addiction Medicine Public Policy Statement: Short Definition of AddictionAddiction 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.
4 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
5 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 rewardingAn area known as the Nucleus Accumbens played a major role in this response
6 Drugs Work In The Midbrain NOT in the Cortexand how do we know this? …MidbrainSurvivalUnconsciousNo free will
7 James Olds, PhD ( )Discovery of the reward system in the midbrainMice will self-administer electric currents to the Ventral Tegmental Area of the midbrainThey prefer the electrical stimulation over other survival rewards such as food
8 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”
9 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.
10 Addiction Neurochemical #1 Dopamine All drugs of abuse and potential compulsive behaviors release DopamineDopamine is the first chemical of a pleasurable experience and is at the heart of all reinforcing experiencesDA is the neurochemical of salience (it signals survival importance)DA signals reward prediction errorTells the brain “this is ‘better than expected’”
11 Addiction Neurochemical #2 Glutamate The most abundant neurochemical in the brainCritical in memory formation & consolidationAll drugs of abuse and many addicting behaviors effect Glutamate which preserves drug memories and creates drug cuesAnd … glutamate is the neurochemical of “motivation” (it initiates drug seeking)
12 DOPAMINE (DA) GLUTAMATE (Glu) All drugs of abuse and potential compulsive behaviors INCREASE DAReward salience“this is important!”“I really want this!”Rostral (toward the nose) projections:PFC < NA < VTAAll drugs of abuse and potential compulsive behaviors EFFECT GluDrug memoriesDrug seeking“OK, I’ll remember”“Fine, go and get it”Caudal (toward the tail) projections:PFC > NA
13 Nucleus Accumbens The release of Dopamine in this area seems to be related to the experience of intense pleasure
14 The Major Brain Areas Included in Addiction Are: Nucleus AccumbensVentral Tegmental Area (VTA)Prefrontal lobeLimbic System
15 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)Addictive DrugsSexual ActivityEatingExerciseMediation, Spirituality, Deep thought, Art, Music, Nature, Socialization
16 Phineas Gage (1823 – 1860) Railroad construction foreman in Vermont Tamping rod driven through his skull by explosionDamage to Left Frontal Lobe and profound personality change“Gage was no longer Gage”
17 Ventral Tegmental Area When stimulated, sends a signal (release of Dopamine) to the Nucleus Accumbens, and then, through the process of reuptake, ends this signalAlso is involved in what has become known, as an Anticipatory signalIf this anticipation can’t be fulfilled, it might be replaced with another behaviorIt is believed many forms of addiction begin here!
18 Prefrontal LobeWilled actions are associated with this area, in contrast to “routine” or “automatic” tasksMediate or inhibit these relatively automatic or “fixed action patterns”, giving these behaviors certain flexibility and relative independence from the environmentDamage to this area can lead toDisinhibited behaviorPerseverationFailure to assess consequences of ones actionsApathyPoor self-monitoring
19 The Frontal Cortex The “Human” Brain Processes judgment, executive decision making,Conscious emotionsConfers emotional meaning onto objects in the worldSeat of the Self and Personality“Love, Morality, Decency, Responsibility, Spirituality”
20 Executive Functioning Abstract thinkingMotivation for goal-directed activityPlanning and problem-solvingAttention to tasksInhibition of impulsive responsesWeighing consequences of future actionsFlexibility of responses (rule shifting)Reflective decision-makingGives us the capacity to use past experience and knowledge to make sense of our current behavior
21 Failure of Executive Functioning Premature, unduly risky, poorly conceived actionsUrgencySensation seekingExpressed emotions inappropriate to the situationDeficits in attention, lack of perseveranceRapid responses without reflection or premeditationInsensitivity to consequencesImpulsive choice (increased delay discounting)
23 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)HippocampusLong-Term Potentiation (LTP): Physical process in which memories are formed- relies on the neurotransmitter Glutamate
24 Putting It All Together 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
25 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
26 Newer theories of addiction suggest that over time, humans have either discovered or manufactured substances that hijack this system, creating addiction
27 In addiction, the drug hijacks the survival hierarchy and is so close to actual survival that it is indistinguishable from actual survivalNew #1 DRUG2. EAT3. KILL4. SEX