Dr. Anna Lembke

There's plenty of red, right? So there's plenty of dopamine transmission in the reward pathway, specifically here in the nucleus accumbens. But if you look at the right-hand column, you'll see that in these individuals who have been using cocaine, methamphetamine, alcohol, and heroin in addictive ways, there's almost no red, which means there's

decreased or below normal levels of dopamine transmission. They are in a chronic dopamine deficit state. This is evidence of the brain trying to compensate for for too much dopamine being triggered by down-regulating its own dopamine production and transmission, not just to baseline but below baseline.

decreased or below normal levels of dopamine transmission. They are in a chronic dopamine deficit state. This is evidence of the brain trying to compensate for for too much dopamine being triggered by down-regulating its own dopamine production and transmission, not just to baseline but below baseline.

And importantly, these individuals who are addicted to these substances, these brain scans were done two weeks after they stopped using.

And importantly, these individuals who are addicted to these substances, these brain scans were done two weeks after they stopped using.

Yeah, which tells us that this dopamine deficit state persists for some period of time. For how long? Well, it depends on the person, but we know at least from this experiment that the first two weeks are this persistent dopamine deficit state, which is consistent with acute withdrawal, right? People feel when they first stop their drug of choice, they feel terrible, right?

Yeah, which tells us that this dopamine deficit state persists for some period of time. For how long? Well, it depends on the person, but we know at least from this experiment that the first two weeks are this persistent dopamine deficit state, which is consistent with acute withdrawal, right? People feel when they first stop their drug of choice, they feel terrible, right?

They experience all of the symptoms of physical withdrawal that correspond with that particular drug they were using, usually the opposite of what the drug did, plus the universal symptoms of withdrawal from any addictive substance or behavior, anxiety, irritability, insomnia, depression, and craving. Now, if they can get through the first 10 to 14 days...

They experience all of the symptoms of physical withdrawal that correspond with that particular drug they were using, usually the opposite of what the drug did, plus the universal symptoms of withdrawal from any addictive substance or behavior, anxiety, irritability, insomnia, depression, and craving. Now, if they can get through the first 10 to 14 days...

What we see clinically is those acute withdrawal symptoms slowly start to get better. And we think that that is mapping on to regenerating dopamine transmission in the reward pathway. And if they can make it to a month, that's usually the point for, on average, based on clinical experience, when people really can start to get out of that

What we see clinically is those acute withdrawal symptoms slowly start to get better. And we think that that is mapping on to regenerating dopamine transmission in the reward pathway. And if they can make it to a month, that's usually the point for, on average, based on clinical experience, when people really can start to get out of that

constant state of craving for their drug of choice and begin to see some light at the end of the tunnel for what their lives might look like if they can maintain abstinence from their drug.

constant state of craving for their drug of choice and begin to see some light at the end of the tunnel for what their lives might look like if they can maintain abstinence from their drug.

Yeah, it's a great question because we have some natural experiments that suggest what might happen if we do that. So as I mentioned before, people with Parkinson's have depletion of dopamine in the substantia nigra. That's what causes that motor disease. The treatment for it is to give L-DOPA, which is a dopamine precursor.

Yeah, it's a great question because we have some natural experiments that suggest what might happen if we do that. So as I mentioned before, people with Parkinson's have depletion of dopamine in the substantia nigra. That's what causes that motor disease. The treatment for it is to give L-DOPA, which is a dopamine precursor.

If I were to give you a spoonful of dopamine, it would do absolutely nothing because it doesn't cross into the brain. It doesn't cross the blood-brain barrier.

If I were to give you a spoonful of dopamine, it would do absolutely nothing because it doesn't cross into the brain. It doesn't cross the blood-brain barrier.

But I could give you L-DOPA, which is a precursor chemical that would cross your blood-brain barrier and get turned into dopamine and then diffusely bind dopamine receptors in your brain in the reward pathway, but also in the movement pathways. When we give patients with Parkinson's dopamine in this form, that can temporarily improve their movements.

But I could give you L-DOPA, which is a precursor chemical that would cross your blood-brain barrier and get turned into dopamine and then diffusely bind dopamine receptors in your brain in the reward pathway, but also in the movement pathways. When we give patients with Parkinson's dopamine in this form, that can temporarily improve their movements.

But in about one in four Parkinson's patients, they will develop a de novo addictive disorder. Shopping addiction, sex addiction, other types of addiction. Because we have the same problem. We are stimulating... the reward pathway with dopamine that is ingested exogenously from the outside.