Hacker News new | past | comments | ask | show | jobs | submit login
Why Dopamine Makes People More Impulsive (knowingneurons.com)
105 points by neurosphere on March 12, 2016 | hide | past | favorite | 39 comments



This is really fascinating to me.

As someone with adhd, my psychiatrist has explained it to me in terms of Dopamine. In his words, stimulant medications help to treat symptoms of adhd, in part, by creating dopamine when we either lack it or have a weakened response to it. This flood of dopamine keeps us from being impulsive, in his explanation.

In other words, I am more impulsive without stimulants and the explanation I was given is that my brain is too busy seeking out dopamine and thus always looking for excitement. By providing dopamine through medication, that seeking behavior diminishes and I am more focused and less impulsive.

So, something doesn't add up. Either my psychiatrist has been misinformed or there is a lot more going on here / my understanding is very off base.


Yes, it is far more complicated than you're describing. I'm going to assume you're taking Adderall (an amphetamine salt mixture), but this also applies to methylphenidate.

First: Stimulant drugs typically release or inhibit reuptake of both dopamine and norepinephrine. Dopamine actually converts into norepinephrine in the brain, complicating things further. L-DOPA, which is described in this article, is not a stimulant drug: it only raises dopamine concentration, and nothing else. It's the direct precursor molecule for dopamine.

Raising norepinephrine along with dopamine can create a focused and patient effect in some people (and sometimes a somewhat euphoric effect); raising just dopamine will generally create a euphoric, relaxing, reward-seeking effect. I don't know the entire pharmacology behind why that is. I seem to recall that DA and NE may be able to directly modulate each other.

Dexedrine (dextroamphetamine), another ADHD medication, has a higher dopamine:norepinephrine ratio than Adderall does (i.e. it releases proportionally more dopamine). It doesn't work for some ADHD sufferers, because they become too euphoric.

Second: Stimulant medication is also more about trying to maintain steady levels of dopamine in the brain at all times, rather than constantly or intermittently fluctuating levels. If you were to take Adderall just once per week, for example, you would probably not get a lot of chronic relief. Taking small doses of L-DOPA every day could maybe help some ADHD sufferers after a week or two (though this is mostly just a theory on my part), for example, but this can lead to psychosis and many other dangerous problems, so is highly discouraged.

Someone please feel free to correct me if I got anything wrong here. I don't have formal education in medicine or neurobiology.


Adderral provides symptom relief almost immediately.


Sure. But it probably doesn't give relief for more than 12 or so hours, right?

When I said "not get a lot of symptom relief", I meant regarding general life functioning, not short-term response. Obviously Adderall will provide quick relief for an ADHD sufferer; it just won't help them in the long-term unless they take it regularly.


> it just won't help them in the long-term unless they take it regularly.

Which is why many ADHD sufferers take stimulant medication regularly. However, that doesn't mean the medication doesn't provide relief that improve general life functioning.

Similarly, chronic pain may be treated with morphine, which provides short-term pain relief and improves general life functioning when taken regularly.

> Stimulant medication is also more about trying to maintain steady levels of dopamine in the brain at all times

I don't think this is accurate. Rather, it depends on the attention and performance requirements of the sufferer. Children may only need symptom relief while in school, whereas adults may need relief through most of their waking hours.

It seems unlikely that someone would really need relief from ADHD symptoms while sleeping.


There is also genetic difference in how fast system clears/consumes the dopamine out - faster means those people are better under stress while worse at prolong concentration, slower means stupor under stress while better in "slow/deep" thinking like math, etc ( obviously it is crude smartphone typed version of a recently mentioned on HN article:)


Dopamine also excites a _downregulating_ part of your brain, that's why it focusses you.

See my comment here: https://news.ycombinator.com/item?id=10368605


That's a major overgeneralization. For one, many people with ADHD who take Adderall for years eventually have to stop taking the drug because their dopamine receptors have downregulated so much and the medication no longer works.


I'm not talking about downregulating receptor response, but entire areas of the brain like the insula and parts of the frontostriatal circuit.


Ah, I see. Sorry for the misunderstanding.

Based on the literature, it seems like a probable explanation.


From what I understand your description is also experimentally validated. People on ADHD medication become like zombies and no longer seek short term excitements that cause distractions.

Perhaps there's something else in ADHD people wiring that cause a different response, but even normal college students took ADHD medication to help focus.


Precisely. It's not that stimulants help people with ADHD focus. They help everyone focus, regardless of whether they have ADHD. [1]

> Attention-deficit drugs increase concentration in the short term, which is why they work so well for college students cramming for exams.

> Versions of these drugs had been given to World War II radar operators to help them stay awake and focus on boring, repetitive tasks.

> And when we reviewed the literature on attention-deficit drugs again in 1990 we found that all children, whether they had attention problems or not, responded to stimulant drugs the same way.

I've always been baffled how I didn't see this for myself years ago - after all, that's exactly what caffeine does for millions of people.

Worse, though, people with ADHD are prescribed stimulants for long-term use, and even after the medicine ceases to be effective - because your body adapts to it over time - you can't just stop taking it, because withdrawal sucks.

[1] http://www.nytimes.com/2012/01/29/opinion/sunday/childrens-a...


So I have ADD, and I can't tell you if my brain is different or not. But I have exactly zero withdrawal from methylphenidate after years of use. If I don't take it, I simply don't get anything done. I have stopped taking it for several week at one point, and then I start spiraling down to my pre-diagnosis state since I forger to eat and sleep.

I get much less impulsive also, car rental managd my own mood much better. My blood pressure add resting heartrate has also improved since I started with the stimulants. A bit unusual according to my doctors.

YMMV - the medication is crude, but being without is not really an option - it's really nice to start being able to plan, and actually decide what actions to take instead of simply doing whatever feelt good at the time.


I don't smoke, but I do use nicotine gum from time to time to help focus. I find it faster acting and more effective than caffeine, with a shorter half-life.

I should probably talk to my doctor to see if I have ADHD, instead of occasionally self-medicating.


It's probably best to not think in terms of a binary ADHD diagnosis, but rather on an attention spectrum.

Students low on the attention spectrum (but either just above ADHD diagnosis or without the resources to get diagnosed) are probably more likely to self-medicate.

So, the fact that some students who self-select for self-medication show improvements isn't necessarily evidence that someone in the middle or upper end of the attention spectrum will see improvements. However, it does suggest a need for research into the effects on randomly selected non-ADHD-diagnosed people.


> People on ADHD medication become like zombies and no longer seek short term excitements that cause distractions.

Definitely not generally true.

Why do people continue saying this?


Because I have ADHD medication and have seen people on it?


Well, quite a lot of other people also take ADHD medication or has friends or relatives that takes them and no, not everyone becomes zombies.

A lot of people just get better lives. YMMW.


I summarized this video by K.C. Berridge about some of his research on dopamine: https://www.youtube.com/watch?v=15TvKADY0QQ

* animals that lose their dopamine learning mechanisms can still learn new things

* even when dopamine is there, sometimes the system will continue to respond to unconditioned responses that are learned and expected

* microinjections of amphetamine do not increase reward expectation - they increase peak of desire for reward - like when food is more tempting after not eating the whole day; sometimes a nasty salty taste is desirable in sodium deficiency, say

* system is computing value, rather than learning

* incentive-salience is a cue-trigged type of wanting; say someone else across the room lighting up a cig cueing your desire

* the cue becomes an attention magnet - the cue is very hard to not want to pay attention to

* the mesolimbic state of brain at a certain instant in time plays a huge role in amplifying responses to cues - hunger increases desire for food, repeated experience of drugs amplify the cue for drugs

* an addict is a person who will have a super strong dopamine response when provided opportunity, due to sensitization of cue-triggered want - even months after enduring withdrawals, acquired hypersensitivity may still exist


I often wonder why we refer to the neurotransmitters as making people depressed/impulsive/etc rather than referring to specific groups of neurons that presumably mediate those experiences or behaviors.


Because the neurotransmitters are all we know enough to experiment with so far.

Like the joke about the drunk looking for his keys only right next to the door - "because that's where the light is".


Psychiatry has convinced a lot of people that mental disorders are often caused by 'chemical imbalances' whatever that means.

The neural structure of the brain is very complex and involves dozens of neuronal molecules acting on a wide variety of neurons.

It's incredible that we have psychiatrists prescribing all sorts of inhibitors/activators to alleviate various disorders. A lot of these drugs have unknown mechanisms. Even when the mechanism is understood no one understands how these drugs are working on the whole brain.


Neuronal pathways are based on a specific neurotransmitters. Dopamine usually means limbic system and seratonin usually means the cortex.


The parent here makes a good point, and your comment appears to represent a common misconception about neurotransmitters. Both dopamine and serotonin can do different things depending on the system and the receptors that are actively present. Serotonin, for example, is mostly in your gut, not cortex! From wikipedia:

"Approximately 90% of the human body's total serotonin is located in the enterochromaffin cells in the GI tract, where it is used to regulate intestinal movements."

Dopamine is more specific, playing an important role in the limbic system, but is not limited to it. Its functions are not completely understood, and again depend on the receptor.

Better to think of the function of neurotransmitters as dependent on both system AND receptor. The function of neurotransmitters, like dopamine, can be simplified, but others, like glutamate, are extremely complicated.


Just got diagnosed with ADHD at 42 years old. Strattera has been a HUGE help.

Of course there are varying degrees of ADHD. But if some of these descriptions fit you. You might have ADHD.

"Everyone encounters some task he doesn't particularly enjoy, but most people are able to find a way to complete the boring aspects of their job, says de Marneffe. People with ADHD, however, have a hard time doing that."

"If you (sometimes) fly off the handle in a fit of anger or frustration one moment but are completely over it in the next, it might be a sign of ADHD."

-you have a hard time sitting for multiple hours

http://www.health.com/health/gallery/0,,20490145,00.html --15 Signs You May Have Adult ADHD--


Doesn't everyone have a hard time completing boring jobs and sitting for hours?


My Dad didn't.

As for me, for some tasks, such as writing documentation for something I knew nobody would ever read, my brain would refuse to focus. I would look for more important things to do and never get a page of documentation done.


How is writing documentation that nobody will ever read a thing anyone should be motivated for?

Do people without ADHD agree to do useless things because they're told to?


If it's that or be fired, I think most people would do what they're told.

There are some people, however, that will, in sheer determination to do what is expected of them, stare anxiously at their screen, hoping to focus their attention to the task at hand. No distractions, just a text editor waiting for some text. The problem is, the thoughts just don't surface. They try to psych themselves up, remember that their lively hood depends on it, that they don't want to let their coworkers down, etc. Sure, their gut tells them that they're working on the wrong solution to the wrong problem, but they remind themselves to keep a good attitude, remembering that this is what their employer deems both valuable and necessary. The hours tick by. It's 6pm, but they're convinced that they'll be able to turn it around. A couple more hours pass by. "If I just get this done, I get to spend time with my family, or go see my friends, or have some semblance of balance." It's 10pm. They cry for a bit, manage to get a bit of work done, and shortly after 1am, they hop in bed and call it a day. As they doze off, they lament their inability to power through uninspiring work (particularly work that they know could be obviated by better practices/tools/business-sense/etc.)

If you've _never_ experienced something like that, then I suppose you either don't have ADHD, or you've only had phenomenal working experiences.


I usually find a way not to do what I consider not worth doing.

I usually ask why the task is worth doing. If they can't come up with a valid response, I try to show them why it's not worth doing. If I can think of a better thing to do, I let them know. If this doesn't work, I will delegate or trade the task with someone else. If that doesn't work, I will often just ignore it. Usually, nobody realizes the job wasn't done, mainly because it wasn't important in the first place. Rarely will I go through the pain of doing something that I realize is not important.

Although I have never been diagnosed with ADHD, I feel like I can relate to some of the symptoms.


The above example isn't the only case where this is relevant. In this case it's something the author doesn't want to do and is pretty boring and pointless and any sane person isn't going to want to do it. Some people can power through it and others won't be able to. You can rewrite the text where the work to be done is maybe not "boring" but tedious and rather than "pointless" it's actually critical that it be done. I've changed the descriptive text above a bit.

> There are some people, that will, in sheer determination to do what needs to be done, stare anxiously at their screen, hoping to focus their attention to the task at hand. No distractions, just a text editor waiting for some text. The problem is, the thoughts just don't surface. They try to psych themselves up, remember that their lively hood depends on it, that they don't want to let their coworkers down, etc. The hours tick by. It's 6pm, but they're convinced that they'll be able to turn it around. A couple more hours pass by. " This is such a critical project I just have to get it done. If I just can just get started, I get to spend time with my family, or go see my friends, or have some semblance of balance." they tell themselves. It's 10pm. They cry for a bit, manage to get a bit of work done, and shortly after 1am, they hop in bed and call it a day. As they doze off, they lament their inability to power through their work and lament their repeated failures.

This was me. I'd have some project to work on, interesting or not and I would have the hardest time getting started. Just getting the first bits and pieces done. Or I'd have a clear picture in my head of how I wanted to do it, what needed to be done, and how I needed to attack it to accomplish it. Then I'd try to get started and fumble about not being able to get that mental picture out into real productive work. I'd spend hours breaking tasks down into smaller bits but not get any of the bits done. I'd think to myself, I'm focused too much on this and I can't think straight any more I'll just take care of another task for a bit and come back to this. Six hours later I've forgotten about it completely and then panic when I realize it. Once it was crunch time, or it was so late the only way to finish was to pull an all nighter I'd some how miraculously get things done well enough to stay out of trouble. I powered through these problems in my 20's by pouring in 15+ hour days regularly. I nearly destroyed my relationship with my wife. I had friends and colleagues that knew I'd get things done but couldn't count on it always being the best quality or on time. I couldn't do that any more when I hit my 30s, started a family, and the toll of the hours and lack of sleep really hit harder. Speaking to my Dr and getting an ADHD diagnosis, some medication and some tools to approach my issues from different angles have been life changing.


yes. Not being able to focus on things you are not interested in was coined "adhd" and some big companies made a lot of money off of it.


That may be true. As for me, I would experience something that is beyond the norm. I have spent 7 hours so far today with a clear head, able to work, with no desire to escape.

Having days where I just stare at the computer for hours with zero ability to really engage in a task is not normal. It didn't happen every day, but enough to help me realize something was not right.

btw, another symptom that I had is zero patience for certain sounds. Clicking pens, dishwasher, and more. My mind would fixate on it. Background noise made it so much harder to focus. Now it is less of a issue.


If this is accurate, is there any research on activities that can regulate dopamine activity and reduce impulsivity?


Dopamine regulates "seeking" behavior. One can direct their "seeking" to good things (achievement of something that benefits your family or community) or bad things (drug induced highs, money at all costs).

Probably educating people on how they are wired to seek things (a good drive when you are talking about going out and securing food/resources) and how to direct that towards healthy pursuits instead of unhealthy ones would go a long way.

Lots of pharmaceuticals can regulate dopamine in various ways too. The issue as it relates to impulsivity seems to be caused by a combination of dopamine driven seeking behavior and more primal parts of the brain hijacking decision making.

It is the combination of primal parts of the brain doing decision making with the brain's propensity for seeking that causes negative impulsivity, so that could be aided by increasing gray matter (meditation) and regulating dopamine (healthy seeking) but you can only do so much.

It seems like so much "crime" is really impulsivity, and so I often have thought about ways you can reduce impulsivity, but it always seems to come at the cost of considerably altering how someone's brain works, which not everyone is open to.


As a layperson, the research I've seen (which focuses on treatment of psychotic disorders) suggests that the only activity known to reliably reduce dopamine activity is taking antipsychotic drugs, a caveat being that there's a decent amount of disagreement as to how big a role dopamine specifically plays in psychotic symptoms (and hence how much we can assume that observed symptom reduction correlates to dopamine antagonism). A major issue with these drugs is that they tend to downregulate dopamine activity very broadly, often screwing up the central nervous system, metabolism, and possibly even immune function. Dopamine seems to be a versatile molecule that gets involved in a lot of processes.


the weird part - impulse control disorders is a well described side effect of the "synthetic" and selective dopamine agonists (pramipexole, ropinirole, rotigotine) developed in the 80's and 90's for PD. It doesn't happen to everyone but seems to affect patients who have some sort of pre-existing obsession or compulsion that was more or less under control prior to the medicine. The odd part is that levodopa (basically good ol' dopamine) does not have this issue...


I'm confused by what you're trying to say. The article repeatedly stated that levodopa has been observed to create higher impulsivity.

I imagine any pure dopamine agonist can be prone to creating an impulse disorder if you take a sufficiently high dose.


The impulsivity seen in patients only happens in the synthetic, and possible more "selective" dopamine agonists that work more with certain dopamine receptor subtypes. Whereas, levodopa, which is a dopamine precursor and presumable not selective at all (ie. works on all receptors) do not have the impulsivity effect, or at least as dramatic, on these same or similar patients.




Consider applying for YC's Spring batch! Applications are open till Feb 11.

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: