Linking Neuroscience, Developmental Psychology, and Personal Experience To Help Understand Addiction

Transcription

1 Linking Neuroscience, Developmental Psychology, and Personal Experience To Help Understand Addiction Marc D. Lewis Radboud University Nijmegen

2 Definitions of addiction Disease model Choice model Social construction of addiction Genetic disorder, which gets triggered by life events Traumatic early history which calls for self-medication

3 These models derive from: Psychology Psychiatry Genetics Prevention/intervention science Sociological perspectives BUT The explosion of neuroscience research pushes us toward new models. These models can guide scientists and practitioners to what is really happening in addiction and where we should focus our efforts. But do scientists (with all those letter after their names) also need help to know where to focus their attention?

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5 A bit about my journey

6 A neuropsychological perspective on the development of addiction 1. A feedback cycle that includes triggers, images, emotion, and action 2. Dopamine released by drug cues (craving) 3. Delay discounting and ego depletion 4. Synaptic shaping: How repeated feedback cycles lead to long-lasting change (incentive sensitization)

7 The classic feedback cycle in addiction Craving Drug imagery

8 Cycle of brain activation Action Planning: A B C Imagining Dopamine Perception Trigger

9 Intensification Trigger/ cue Craving Learning Relief Loss Imagining Using Sensitization

10 Delay Discounting

11 Dopamine, desire, and delay discounting Raphe nucleus Serotonin Locus coeruleus Norepinephrine Nucleus of Meynert Acetylcholine Ventral tegmental area (VTA) Dopamine

12 Dopamine focuses attention on the immediate goal. which generates craving

13 Craving traps you in delay discounting Because of the dopamine pump Happy girlfriend Intensity of desire Dopamine Craving is not just a steady state. Drug Time Value rises steeply as the reward gets closer in time

14 How math imitates life Why is that man going after the cake? Because it seems worth more than imagined future happiness which registers down here because dopamine is tuned to the cake.

15 The grip of the immediate goal outweighs the imagined future!

16 Ego Depletion

17 Hungry?

18 The location of two centres for cognitive control ACC

19 Cues, cues, cues

20 The role of self-confidence (belief in one s own capacity for self-control I can do it!

21 From: PLOS 1, Dissociated Grey Matter Changes with Prolonged Addiction and Extended Abstinence in Cocaine Users. Colm G. Connolly, Ryan P. Bell, John J. Foxe, Hugh Garavan

22 Synaptic modification Hebb s law: What fires together wires together Marc s law: What wires together makes up networks of linked neurons that underlie ALL our habits Good habits: being in love with your partner or children playing or listening to music riding your bike to work Bad habits: drug addiction any other addiction voting conservative

23 Addiction may be viewed as accelerated learning of a specific habit, in response to a narrowing range of cues Craving/imagining synaptic growth Doing! Proliferation of drug-oriented synaptic networks Pruning (weakening) of alternative networks Pruning (or decoupling) of cognitive-control networks

24 A neurodevelopmental model of addiction Synaptic connections are modified, forming coherent networks -- habits This process is accelerated in response to highly attractive goals, along with As mediated by dopamine, released to the striatum and related areas Those synaptic networks support not only behavioural habits but also the formation of beliefs, values, and meaning These networks trigger more dopamine release whenever activated by addictive cues which is why they re self-perpetuating Thus a developmental process of increasing sensitization Meanwhile, reduced cognitive control due to ego depletion and giving up, leads to reduced capacity of networks such as ACC

25 A neurodevelopmental model must explain individual differences Developmental sensitivity, especially in adolescence The role of the environment: trauma and unmet needs: Gabor Mate s bigger picture Drug choice as a result of individual s history? Helplessness/boredom need for engagement/power dopamine+norepinephrine Anxiety about loss, rejection need for warmth/closeness opioids Substitution of drugs for inadequate parenting Methamphetamine = dopamine norepinephrine serotonin Heroin, morphine = opioids norepinephrine Thus, the kinds of drugs we seek help fulfill the kinds of needs that are unmet.

26 What can addiction neuroscience contribute to the goals of harm reduction? Sensitization: the power or cues to trigger the growth of addictive networks that are self-perpetuating Seek to minimize addictive cues by helping clients modify their environments or daily activities. Delay discounting: Desire isn t free. That dopamine surge traps people in the present tense. Ego depletion/giving up control. The chemistry of different drugs represents unique interpersonal losses and gains. Minimize craving by encouraging moderate use or replacement drug use. AND/OR Help clients connect with their future. Provide control until cortical control regions grow back if ever they do Provide activities/relationships to make up for what s gone missing. AND/OR Provide chemical replacements to tide people over, for now or for good.

27 Amsterdam s steps toward harm reduction 00:40 seconds to 6:00

28 From: PLOS 1, Dissociated Grey Matter Changes with Prolonged Addiction and Extended Abstinence in Cocaine Users. Colm G. Connolly, Ryan P. Bell, John J. Foxe, Hugh Garavan

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30 What you grow might be more useful than what you lost!

31 Lending control Helping clients connect with their future selves Minimizing addictive cues Craving Drug imagery Minimizing craving by encouraging moderate use or replacement Providing replacement activities/relationships

32 The value of scientific knowledge for addicts trying to quit or just maintain My book and blog attempted to connect my lived experience with the neuroscience of addiction They were not intended as tools of self-help or harm reduction But here s an I got yesterday Hello Marc, My name is ---. I'm from ---. I just, this past year, endured my first full year of sobriety after going through the inpatient program at a fantastic facility called The Harrison House. It was my first time going over a week sober since I was roughly thirteen. I just felt the need to thank you for the emense amount of information I have taken in, thanks to your blog. If my counselor, Eric, at the Harrison House, hadn't referenced so much detailed information from this site I wouldnt have the critical knowledge about how the brain works which in turn would have made myself not understand, nor respect the power of addiction. Me being the stubborn ass that I am, I refuse to believe anything without physical proof. Thanks to your site I now have the knowledge and the power to allow myself to live a (relatively) normal life. After all I am a drug addict. Haha. Anyhow I am forever grateful for what you do and just needed to let you know that. I would probably be dead by now without it.

33 A final word from neuroscience: The brain never stops growing