Never Enough: The Neuroscience and Experience of Addiction | Judy Grisel | TEDxPSU

[Music] [Applause] by the time they graduate from high school 70% of kids will have drunk alcohol half will have tried an illegal drug and about close to that many will have smoked or vape nicotine one in five will have used prescriptions off-label these numbers are critical because one of the primary factors in developing substance use disorders is early exposure it's a fact that the majority of people who have a substance use disorder began using before they were 18 for instance if you start drinking by 14 you have seven times the chance of developing an alcohol problem then you would if you had waited until you were 21 or longer so why do kids take these risks well they're primed for those risks and in fact through most of our evolutionary history high risk taking and novelty seeking and low respect for adults and authorities have benefited the population as a whole it's great to have a bunch of contrary risk takers living alongside more cautious folks so that we have a balance between progress and caution and these changes are also really good for them individually because it helps them to develop their own identities this tendency to experiment and take risks is built into the way the brain develops there's a gap between the development of reward pathways and motivation which happens quicker than those for caution and impulse control and abstract reasoning and that serves them again by helping them to develop their identities and it serves the rest of us about 10,000 people die everyday from drug abuse around the world and I should have been one of those I took my first drink at 13 and was off to the races I spent the next ten years taking as many mind-altering chemicals as I could get my hands on and as a result of that I was kicked out of three schools I became homeless I contracted hepatitis C and I ended up in treatment right after my 23rd birthday I thought it was going to be a spa this was in the 80s so I had no idea what treatment was but I I got to a treatment center and they said there that if I wanted to live I was gonna have to be abstinent which I thought was terrible deal I wasn't sure but I figured there was a back way if I had an illness that was killing me I was going to figure out a cure for the illness and then I would be able to use without dying so I eventually got a PhD in neuroscience and I've been researching in the field since then and I haven't solved it and nobody else has either what we know is that addiction is characterized by craving and compulsive use tolerance meaning that the drug works less and less well over time and dependence so that when the drugs go away you feel less good than normal and those things are are mediated by about half of it the risk comes from genetics and the genetic factors include things like those we've been talking about so the tendency toward novelty seeking and risk-taking is higher in adolescents in adults but in some adolescents more than others environmental factors include things like access and stress and developmental factors are really important so adverse experiences early in your life really prime a person for developing an addiction as they use to cope but also just any adolescent exposure really increases the risk so to talk about what addiction is I thought I'd give you this model and start with the idea that we have a feeling state homeostatic aliy maintained baseline so if I bumped into you on the street later and I said how are you doing and you said I'm doing fine that would be your homeostasis yours might be different than mine but we all have one this is really actively maintained by the nervous system and it's necessary so that we know if something good or bad happens for instance if it's your birthday and you have a great day you'll feel better than that and that's how you know you know something wonderful has happened I don't know if you've noticed but the day after your birthday it's usually a little bit of a letdown you don't go right back to your middle baseline that great day you had kind of comes with the cost and then you return to baseline the same thing can happen if an adverse experience occurs so you feel maybe worried or threatened if that threat goes away then you feel relaxed and especially cooled before again returning to baseline so basically we start with this homeostatic lis maintained feeling state that we kind of move around as good and bad things happen and that's how we know if good and bad things happen well some of us learn that alcohol and other drugs can cause changes in that feeling state to make us feel better than our homeostatic lis maintained baseline but you'll notice probably that even a drink or two has a little cost it might be that you feel not quite normal or a little bit hungover or you don't sleep as well and then you come back to your baseline but we don't have to stop with a drink or two do we so you could have more than one drink or maybe throw in a little weed and that would be better so we can we can control the delivery of these things you can only have so many birthdays right and you can even take more than just the alcohol in the weed and get really happy so that seems great except it's not from the brains perspective and the brain will adapt to cause tolerance so that you're not quite as happy and even eventually enough tolerance that you're really feeling basically normal with your drugs that adaptation is to maintain the baseline and that also happens when you take the drugs away is when you really notice it so if you're now normal with the drugs when the drugs are gone you're on the opposite extreme so I thought we could take an example when that's kind of close to my heart I liked all the drugs I could find but I especially liked smoking marijuana and this is popular today about 40% of kids smoked that hasn't changed in the last few years so much but what has change is that they're smoking more so many more smoking daily or frequently and I thought I'd describe how marijuana works on the brain and how homeostasis is maintained so marijuana works THC is the active ingredient that produces the high and it activates this endocannabinoid system that we naturally have so inand my dand to arachidonic juicer all or 2ag are neurotransmitters that interact with all the black spots you're looking at all over the brain all over the cortex and areas associated with learning and memory associated with motivation associated with reward and when those chemicals interact they have an effect obviously our brain wouldn't make these for no reason I thought I would explain the effect by telling a story about my dog my puppy it was now a hundred pounds but when he was little he was walking around the front yard one day and my daughter dropped a piece of bacon and I could really practically see his brain light up he didn't know there was bacon certainly not living in the grass and I imagine that his olfactory areas and his taste sensory cortex his reward areas may be learning in memory all were activated with little squirts of an and amide or two AG to sort of let him know Wow bacon this is awesome the same thing happens for us I don't know what your bacon is it might be a great line of poetry or music or some wonderful idea you have or a good talk but you'll release these chemicals to let you know that's something really salient or relevant is going on the reason this system is all over the brain is because we never know what exactly we're going to find important it helps us to sort what's important by sort of highlighting those events or experience that are particularly meaningful and this plays a big role in learning in memory and it really helps us sort what we care about and what we don't care about no THC is a little different isn't it because it's not sympathize synthesized and released when we have great experiences we just smoke it in a bong or a high potency joint and it goes all over the brain and it all those interacts in all those black spots so in other words everything is bacon which is a lot of fun I think I loved that you know everything was so more much more rich and meaningful and even a tedious day at work could be interesting of course the brain doesn't like it this way because then you can really can't tell when something important happens so it compensates and the way it does is illustrated in this picture of again rat brains on the left your left is a rat that has had no THC or tasty like analog and on the right is a brain all the way on the right that had a high dose for about 14 days and I bet that my brain when I stopped smoking looked a lot like the one on the right and what it felt like to me was that nothing was really interesting nothing was motivating nothing was really worthwhile time with my family yeah you know my aspirations not so important anymore the only way in fact that I could find anything worth doing was to be completely stoned this happens to people who smoke a lot of weed you can see in the green all the areas that there's these interaction sites are lost and regular smokers and if this is occurring during development when meaning is so important we're supposed to be trying new things and figuring out who we are then the cortex is organized differently those effects in blue are probably permanent and they lead to a kind of a different way of processing information one important thing about the way we process information if we smoke a lot of weed is that what we used to find rewarding and pleasurable is no longer that important so back to our model it's fun to get high acute with the occasional use but if you do it regularly your brain is going to adapt getting rid of those interaction sites so that now you're not really high and when the weed goes away there's a lot of despair substance abuse is the number one killer for people under 50 and if we take addictive drugs on a regular basis they cause feeling states exactly opposite to the ones we want to have when I started smoking weed I loved how it made everything interesting and fun by the time I quit smoking nothing was interesting and nothing was fun thank you for listening you

Channel: TEDx Talks

Views: 135,008

Keywords: TEDxTalks, English, Health, Cognitive science, Drugs, Illness, Medical research, Neuroscience, Psychology

Id: rnt1eb9vQxA

Length: 12min 14sec (734 seconds)

Published: Mon Feb 24 2020