Can dopamine receptors tell us who is more likely to develop an alcohol use disorder?
The effect of using risky substances, such as alcohol, on the brain’s so-called “reward system” has received considerable attention, both scientifically and in the wider public discourse, particularly in terms of what it signifies for the risk of developing a substance use disorder. This study measured receptor availability for dopamine, a neurotransmitter that is abundant throughout a part of the reward system called the ventral striatum, in people without a history of alcohol use disorder, and tested whether it predicted risk for harmful alcohol use many years later.
Using a type of brain imaging to estimate dopamine receptor levels called positron emission tomography (PET), in a sample of drinkers without a history of alcohol use disorder this study tested whether lower dopamine receptor levels predict later levels of traits and behaviors associated with alcohol use disorder, including harmful and hazardous alcohol use, greater impulsivity, and greater reward sensitivity. This study is one of the first to use a PET imaging technique to explore the relationship between dopamine receptor levels and the development of substance use disorders over time. This line of inquiry could have important downstream implications for the use of biomarkers like neurotransmitter availability to identify risk for future substance use problems.
HOW WAS THIS STUDY CONDUCTED?
The study recruited 68 participants (5 women and 10 sets of male twins) from a pool of individuals who had previously participated in brain imaging studies as healthy volunteers at the Karolinska Institutet in Stockholm between 2002 and 2010. All participants drank alcohol but had no history of severe substance use disorders, mental health disorders, or major medical conditions. The study involved two components: brain imaging and follow-up assessments. Initially, participants underwent PET scans to measure dopamine receptor availability in the brain. Subsequently, 8 to 16 years later, participants completed online questionnaires to assess their alcohol and drug use, impulsivity (e.g., “I consider myself to be impulsive,” and/or, “I am restless at the theater or lectures.”), reward sensitivity (a measure of how much someone is motivated by reward; e.g., “When I get something I want, I feel excited and energized.”), and family history of alcohol or drug issues.
The researchers examined the relationship between dopamine receptor availability in the brain and each of the outcomes (e.g., harmful alcohol use), adjusting factors like age, family history, and questionnaire scores.
Participants were approximately 30 years old at the time of their initial brain scans, ranging from 10 to 59 years. During the follow-up assessment, their average age was 42 years, with a range of 23 to 74. Regarding alcohol use, participants scored an average of 4.3 on the Alcohol Use Disorder Identification Test (AUDIT), with scores ranging from 1 to 11 (8 is the threshold for hazardous drinking and 16 the threshold for a likely diagnosis of alcohol use disorder). For drug use, measured using the Drug Use Disorder Identification Test (DUDIT), participants had an average score of 0.4, ranging from 0.0 to 8.0, suggestive of very little (non-alcohol) drug use in this sample. In terms of family history, participants reported either the presence or absence of family history of either alcohol use disorder or other substance use disorder.
Impulsivity in the context of particular situations (i.e., state-like) was assessed using the Barratt Impulsiveness Scale. The group had an average score of 57.5, with scores ranging from 44.0 to 74.0. Impulsivity, as indicated by a more general behavioral pattern (i.e., trait-like), was measured by the Sensation-Seeking Scale with an average score of 6.6, ranging from 1.0 to 14.0. Participants’ average score for reward sensitivity, assessed through the Sensation-Seeking Reward Questionnaire, was 5.5, with scores ranging from 0.0 to 17.0.
The striatal dopamine receptor binding potential, indicating dopamine receptor availability in the brain, averaged 2.9 and ranged from 2.3 to 3.8, reflecting variations in dopamine levels among participants. With respect to family history, 33.8% of participants had a family history of alcohol use disorder, while 7.4% had a family history of other substance use disorder.
WHAT DID THIS STUDY FIND?
No strong link was observed between dopamine receptor availability and hazardous alcohol consumption.
There was not a strong association between dopamine receptor availability in the brain and alcohol consumption. In simpler terms, the study did not find that dopamine receptor levels could predict the quantity of alcohol individuals in this sample would consume.
Figure 2. This graph represents the trend line in a scatter plot. A line at an angle indicates a positive or negative association depending on the direction, but the closer the line is to being flat, the less of an association there is. The findings in this graph indicate that the relationship between dopamine receptor availability and hazardous drinking was not very strong.
Lower dopamine receptor levels were correlated with slightly higher impulsivity, but not with reward sensitivity.
Regarding impulsivity, a modest yet statistically reliable link emerged. Lower dopamine receptor levels correlated with higher impulsivity when impulsivity was measured as a trait (i.e., long-standing pattern of behavior) but not for impulsivity when measured as a state (i.e., current risk for impulsive behavior). Furthermore, dopamine receptor levels did not significantly relate to reward sensitivity. In other words, the number and availability of dopamine receptors within the ventral striatum was not predictive of the extent to which these individuals were motivated by reward.
Having a family history of alcohol use disorder did not alter the general pattern of effects.
Despite earlier research suggesting an association, this study did not demonstrate a strong influence of family history of alcohol or other drug use disorder on the relationship between dopamine receptor availability and alcohol consumption or related factors. Also importantly, the findings showing no association between dopamine receptors and later hazardous drinking were similar both for individuals with and without a family history of substance use disorder.
WHAT ARE THE IMPLICATIONS OF THE STUDY FINDINGS?
The study examined 68 drinkers without a history of alcohol use disorder to test whether the dopamine receptor availability predicted later alcohol use 8 to 16 years later. Though no significant association was detected for this primary aim, small associations were observed between dopamine receptor and impulsivity, suggesting that this brain marker might predict traits associated with drinking problems like impulsivity though not alcohol use per se, particularly for individuals without alcohol use disorder.
These findings indicate that dopamine receptor availability can affect individuals differently, particularly concerning impulsivity. Understanding this individual variability is crucial when exploring how biological factors influence behavior. Moreover, the relationship between dopamine receptor availability and alcohol use appears to be complex, influenced by multiple factors beyond dopamine receptor levels. Regarding impulsivity, the study revealed that lower dopamine receptor availability correlated with heightened impulsivity, measured as a broader facet of impulsivity (i.e., “trait”) but not when measured as specific situational impulsivity (i.e., “state”). The study’s findings also challenge previous assumptions about dopamine receptor availability, hinting that it might function as a state-like marker that changes with alcohol use, rather than a stable trait-like predictor of alcohol-related behaviors. Family history of alcohol use disorder surprisingly did not influence the relationship between dopamine receptor availability and alcohol use or related factors. This unexpected result suggests further exploration into genetic influences beyond family history may be fruitful.
As we gain more insights into the link between dopamine receptor availability and impulsivity, personalized interventions targeting specific aspects of impulsivity in individuals with alcohol-related issues may become possible. In sum, this study adds greater nuance to our understanding of dopamine receptor availability’s role in alcohol-related behaviors and emphasizes the need for personalized and targeted approaches to study and address these issues.
The study had a moderately sized group for PET research, but it lacked diversity in terms of sex/gender, with only five females. This means the findings might not apply equally to men and women, emphasizing the need for more gender-balanced studies in the future.
The study did not report sample race/ethnicity so generalizability beyond White Swedish people is unknown.
The study included people ranging from 10 to 59 years old during their PET scans, which can complicate the relationship between dopamine receptor availability and age. The participant age range at the time of initial scanning, which included participants who were children, may have made it less likely to detect any effect between dopamine receptor level and later drinking. While the study made adjustments based on existing research, the wide age range makes it important to be cautious in interpreting the results. Future research might benefit from focusing on specific age groups.
Most participants reported drinking alcohol at levels below what is considered risky on measures of alcohol consumption, which reflects the study’s focus on individuals without a history of alcohol use disorder. However, it means the findings might not apply to people who have more serious alcohol issues. Future research should look at a wider range of alcohol consumption.
The study collected data on alcohol use and related factors during follow-up, not at the same time as the PET scans. This time gap makes it challenging to directly link striatal dopamine receptor availability and scores on measures of alcohol consumption at the time of the PET scans, introducing potential timing-related factors.
BOTTOM LINE
This quasi-longitudinal study of 68 participants found no relationship between dopamine receptor levels and future alcohol consumption, reward sensitivity, or family history, and only a modest-sized link to some impulsivity traits, all of which suggests that this brain marker may not be well-suited to predicting later hazardous drinking for those with no history of alcohol use disorder. While the study, given its design and limitations, does not necessarily suggest that dopamine receptor levels are linked to risk of lower risk drinking progressing to alcohol use disorder, the line of inquiry is worthy of future, more rigorous research to determine if other neurobiological factors may play a more substantive role.
For individuals and families seeking recovery: This study deepens our knowledge of how the brain is (and is not) involved in the development of alcohol use disorder, though the use of potential biomarkers to detect risk for future alcohol use disorder is in need of refinement, particularly in terms of linking such insights with managing the practical aspects of recovery, such as accessing various resources that enable individuals to begin and maintain recovery (i.e., recovery capital). Therefore, the utility of the findings from this study for individuals and families in recovery is limited.
For treatment professionals and treatment systems: Recovery encompasses a wide range of factors necessitating holistic and personalized treatment approaches. Although this research provides valuable insights into the neurobiological aspects of addiction, there is a need to better connect these insights with practical aspects of recovery, like accessing resources that support individuals in starting and sustaining their recovery journey, known as “recovery capital.” Consequently, the applicability of the study’s findings for treatment professionals and systems is somewhat limited.
For scientists: The limbic dopaminergic system has long been implicated in addiction. This somewhat rare prospective study adds to our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, and therefore holds significant value for scientists working in substance use disorder and neuroscience. These findings inform further research into refining our understanding of addiction mechanisms and developing more targeted interventions.
For policy makers: This study deepens our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, yet its findings do not point to opportunities for direct policy actions. Policy makers might recognize the importance of multifaceted strategies to prevent and treat alcohol-related issues, particularly among high-risk populations. While this study offers insights into the brain’s role in addiction, it underscores the need for a comprehensive approach that considers a multitude of etiological pathways into alcohol use disorder. Effective policies and interventions should attend to the dynamic interaction of risk factors across bio-psycho-social levels to create a more impactful response to alcohol-related harms.
Using a type of brain imaging to estimate dopamine receptor levels called positron emission tomography (PET), in a sample of drinkers without a history of alcohol use disorder this study tested whether lower dopamine receptor levels predict later levels of traits and behaviors associated with alcohol use disorder, including harmful and hazardous alcohol use, greater impulsivity, and greater reward sensitivity. This study is one of the first to use a PET imaging technique to explore the relationship between dopamine receptor levels and the development of substance use disorders over time. This line of inquiry could have important downstream implications for the use of biomarkers like neurotransmitter availability to identify risk for future substance use problems.
HOW WAS THIS STUDY CONDUCTED?
The study recruited 68 participants (5 women and 10 sets of male twins) from a pool of individuals who had previously participated in brain imaging studies as healthy volunteers at the Karolinska Institutet in Stockholm between 2002 and 2010. All participants drank alcohol but had no history of severe substance use disorders, mental health disorders, or major medical conditions. The study involved two components: brain imaging and follow-up assessments. Initially, participants underwent PET scans to measure dopamine receptor availability in the brain. Subsequently, 8 to 16 years later, participants completed online questionnaires to assess their alcohol and drug use, impulsivity (e.g., “I consider myself to be impulsive,” and/or, “I am restless at the theater or lectures.”), reward sensitivity (a measure of how much someone is motivated by reward; e.g., “When I get something I want, I feel excited and energized.”), and family history of alcohol or drug issues.
The researchers examined the relationship between dopamine receptor availability in the brain and each of the outcomes (e.g., harmful alcohol use), adjusting factors like age, family history, and questionnaire scores.
Participants were approximately 30 years old at the time of their initial brain scans, ranging from 10 to 59 years. During the follow-up assessment, their average age was 42 years, with a range of 23 to 74. Regarding alcohol use, participants scored an average of 4.3 on the Alcohol Use Disorder Identification Test (AUDIT), with scores ranging from 1 to 11 (8 is the threshold for hazardous drinking and 16 the threshold for a likely diagnosis of alcohol use disorder). For drug use, measured using the Drug Use Disorder Identification Test (DUDIT), participants had an average score of 0.4, ranging from 0.0 to 8.0, suggestive of very little (non-alcohol) drug use in this sample. In terms of family history, participants reported either the presence or absence of family history of either alcohol use disorder or other substance use disorder.
Impulsivity in the context of particular situations (i.e., state-like) was assessed using the Barratt Impulsiveness Scale. The group had an average score of 57.5, with scores ranging from 44.0 to 74.0. Impulsivity, as indicated by a more general behavioral pattern (i.e., trait-like), was measured by the Sensation-Seeking Scale with an average score of 6.6, ranging from 1.0 to 14.0. Participants’ average score for reward sensitivity, assessed through the Sensation-Seeking Reward Questionnaire, was 5.5, with scores ranging from 0.0 to 17.0.
The striatal dopamine receptor binding potential, indicating dopamine receptor availability in the brain, averaged 2.9 and ranged from 2.3 to 3.8, reflecting variations in dopamine levels among participants. With respect to family history, 33.8% of participants had a family history of alcohol use disorder, while 7.4% had a family history of other substance use disorder.
WHAT DID THIS STUDY FIND?
No strong link was observed between dopamine receptor availability and hazardous alcohol consumption.
There was not a strong association between dopamine receptor availability in the brain and alcohol consumption. In simpler terms, the study did not find that dopamine receptor levels could predict the quantity of alcohol individuals in this sample would consume.
Figure 2. This graph represents the trend line in a scatter plot. A line at an angle indicates a positive or negative association depending on the direction, but the closer the line is to being flat, the less of an association there is. The findings in this graph indicate that the relationship between dopamine receptor availability and hazardous drinking was not very strong.
Lower dopamine receptor levels were correlated with slightly higher impulsivity, but not with reward sensitivity.
Regarding impulsivity, a modest yet statistically reliable link emerged. Lower dopamine receptor levels correlated with higher impulsivity when impulsivity was measured as a trait (i.e., long-standing pattern of behavior) but not for impulsivity when measured as a state (i.e., current risk for impulsive behavior). Furthermore, dopamine receptor levels did not significantly relate to reward sensitivity. In other words, the number and availability of dopamine receptors within the ventral striatum was not predictive of the extent to which these individuals were motivated by reward.
Having a family history of alcohol use disorder did not alter the general pattern of effects.
Despite earlier research suggesting an association, this study did not demonstrate a strong influence of family history of alcohol or other drug use disorder on the relationship between dopamine receptor availability and alcohol consumption or related factors. Also importantly, the findings showing no association between dopamine receptors and later hazardous drinking were similar both for individuals with and without a family history of substance use disorder.
WHAT ARE THE IMPLICATIONS OF THE STUDY FINDINGS?
The study examined 68 drinkers without a history of alcohol use disorder to test whether the dopamine receptor availability predicted later alcohol use 8 to 16 years later. Though no significant association was detected for this primary aim, small associations were observed between dopamine receptor and impulsivity, suggesting that this brain marker might predict traits associated with drinking problems like impulsivity though not alcohol use per se, particularly for individuals without alcohol use disorder.
These findings indicate that dopamine receptor availability can affect individuals differently, particularly concerning impulsivity. Understanding this individual variability is crucial when exploring how biological factors influence behavior. Moreover, the relationship between dopamine receptor availability and alcohol use appears to be complex, influenced by multiple factors beyond dopamine receptor levels. Regarding impulsivity, the study revealed that lower dopamine receptor availability correlated with heightened impulsivity, measured as a broader facet of impulsivity (i.e., “trait”) but not when measured as specific situational impulsivity (i.e., “state”). The study’s findings also challenge previous assumptions about dopamine receptor availability, hinting that it might function as a state-like marker that changes with alcohol use, rather than a stable trait-like predictor of alcohol-related behaviors. Family history of alcohol use disorder surprisingly did not influence the relationship between dopamine receptor availability and alcohol use or related factors. This unexpected result suggests further exploration into genetic influences beyond family history may be fruitful.
As we gain more insights into the link between dopamine receptor availability and impulsivity, personalized interventions targeting specific aspects of impulsivity in individuals with alcohol-related issues may become possible. In sum, this study adds greater nuance to our understanding of dopamine receptor availability’s role in alcohol-related behaviors and emphasizes the need for personalized and targeted approaches to study and address these issues.
The study had a moderately sized group for PET research, but it lacked diversity in terms of sex/gender, with only five females. This means the findings might not apply equally to men and women, emphasizing the need for more gender-balanced studies in the future.
The study did not report sample race/ethnicity so generalizability beyond White Swedish people is unknown.
The study included people ranging from 10 to 59 years old during their PET scans, which can complicate the relationship between dopamine receptor availability and age. The participant age range at the time of initial scanning, which included participants who were children, may have made it less likely to detect any effect between dopamine receptor level and later drinking. While the study made adjustments based on existing research, the wide age range makes it important to be cautious in interpreting the results. Future research might benefit from focusing on specific age groups.
Most participants reported drinking alcohol at levels below what is considered risky on measures of alcohol consumption, which reflects the study’s focus on individuals without a history of alcohol use disorder. However, it means the findings might not apply to people who have more serious alcohol issues. Future research should look at a wider range of alcohol consumption.
The study collected data on alcohol use and related factors during follow-up, not at the same time as the PET scans. This time gap makes it challenging to directly link striatal dopamine receptor availability and scores on measures of alcohol consumption at the time of the PET scans, introducing potential timing-related factors.
BOTTOM LINE
This quasi-longitudinal study of 68 participants found no relationship between dopamine receptor levels and future alcohol consumption, reward sensitivity, or family history, and only a modest-sized link to some impulsivity traits, all of which suggests that this brain marker may not be well-suited to predicting later hazardous drinking for those with no history of alcohol use disorder. While the study, given its design and limitations, does not necessarily suggest that dopamine receptor levels are linked to risk of lower risk drinking progressing to alcohol use disorder, the line of inquiry is worthy of future, more rigorous research to determine if other neurobiological factors may play a more substantive role.
For individuals and families seeking recovery: This study deepens our knowledge of how the brain is (and is not) involved in the development of alcohol use disorder, though the use of potential biomarkers to detect risk for future alcohol use disorder is in need of refinement, particularly in terms of linking such insights with managing the practical aspects of recovery, such as accessing various resources that enable individuals to begin and maintain recovery (i.e., recovery capital). Therefore, the utility of the findings from this study for individuals and families in recovery is limited.
For treatment professionals and treatment systems: Recovery encompasses a wide range of factors necessitating holistic and personalized treatment approaches. Although this research provides valuable insights into the neurobiological aspects of addiction, there is a need to better connect these insights with practical aspects of recovery, like accessing resources that support individuals in starting and sustaining their recovery journey, known as “recovery capital.” Consequently, the applicability of the study’s findings for treatment professionals and systems is somewhat limited.
For scientists: The limbic dopaminergic system has long been implicated in addiction. This somewhat rare prospective study adds to our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, and therefore holds significant value for scientists working in substance use disorder and neuroscience. These findings inform further research into refining our understanding of addiction mechanisms and developing more targeted interventions.
For policy makers: This study deepens our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, yet its findings do not point to opportunities for direct policy actions. Policy makers might recognize the importance of multifaceted strategies to prevent and treat alcohol-related issues, particularly among high-risk populations. While this study offers insights into the brain’s role in addiction, it underscores the need for a comprehensive approach that considers a multitude of etiological pathways into alcohol use disorder. Effective policies and interventions should attend to the dynamic interaction of risk factors across bio-psycho-social levels to create a more impactful response to alcohol-related harms.
Using a type of brain imaging to estimate dopamine receptor levels called positron emission tomography (PET), in a sample of drinkers without a history of alcohol use disorder this study tested whether lower dopamine receptor levels predict later levels of traits and behaviors associated with alcohol use disorder, including harmful and hazardous alcohol use, greater impulsivity, and greater reward sensitivity. This study is one of the first to use a PET imaging technique to explore the relationship between dopamine receptor levels and the development of substance use disorders over time. This line of inquiry could have important downstream implications for the use of biomarkers like neurotransmitter availability to identify risk for future substance use problems.
HOW WAS THIS STUDY CONDUCTED?
The study recruited 68 participants (5 women and 10 sets of male twins) from a pool of individuals who had previously participated in brain imaging studies as healthy volunteers at the Karolinska Institutet in Stockholm between 2002 and 2010. All participants drank alcohol but had no history of severe substance use disorders, mental health disorders, or major medical conditions. The study involved two components: brain imaging and follow-up assessments. Initially, participants underwent PET scans to measure dopamine receptor availability in the brain. Subsequently, 8 to 16 years later, participants completed online questionnaires to assess their alcohol and drug use, impulsivity (e.g., “I consider myself to be impulsive,” and/or, “I am restless at the theater or lectures.”), reward sensitivity (a measure of how much someone is motivated by reward; e.g., “When I get something I want, I feel excited and energized.”), and family history of alcohol or drug issues.
The researchers examined the relationship between dopamine receptor availability in the brain and each of the outcomes (e.g., harmful alcohol use), adjusting factors like age, family history, and questionnaire scores.
Participants were approximately 30 years old at the time of their initial brain scans, ranging from 10 to 59 years. During the follow-up assessment, their average age was 42 years, with a range of 23 to 74. Regarding alcohol use, participants scored an average of 4.3 on the Alcohol Use Disorder Identification Test (AUDIT), with scores ranging from 1 to 11 (8 is the threshold for hazardous drinking and 16 the threshold for a likely diagnosis of alcohol use disorder). For drug use, measured using the Drug Use Disorder Identification Test (DUDIT), participants had an average score of 0.4, ranging from 0.0 to 8.0, suggestive of very little (non-alcohol) drug use in this sample. In terms of family history, participants reported either the presence or absence of family history of either alcohol use disorder or other substance use disorder.
Impulsivity in the context of particular situations (i.e., state-like) was assessed using the Barratt Impulsiveness Scale. The group had an average score of 57.5, with scores ranging from 44.0 to 74.0. Impulsivity, as indicated by a more general behavioral pattern (i.e., trait-like), was measured by the Sensation-Seeking Scale with an average score of 6.6, ranging from 1.0 to 14.0. Participants’ average score for reward sensitivity, assessed through the Sensation-Seeking Reward Questionnaire, was 5.5, with scores ranging from 0.0 to 17.0.
The striatal dopamine receptor binding potential, indicating dopamine receptor availability in the brain, averaged 2.9 and ranged from 2.3 to 3.8, reflecting variations in dopamine levels among participants. With respect to family history, 33.8% of participants had a family history of alcohol use disorder, while 7.4% had a family history of other substance use disorder.
WHAT DID THIS STUDY FIND?
No strong link was observed between dopamine receptor availability and hazardous alcohol consumption.
There was not a strong association between dopamine receptor availability in the brain and alcohol consumption. In simpler terms, the study did not find that dopamine receptor levels could predict the quantity of alcohol individuals in this sample would consume.
Figure 2. This graph represents the trend line in a scatter plot. A line at an angle indicates a positive or negative association depending on the direction, but the closer the line is to being flat, the less of an association there is. The findings in this graph indicate that the relationship between dopamine receptor availability and hazardous drinking was not very strong.
Lower dopamine receptor levels were correlated with slightly higher impulsivity, but not with reward sensitivity.
Regarding impulsivity, a modest yet statistically reliable link emerged. Lower dopamine receptor levels correlated with higher impulsivity when impulsivity was measured as a trait (i.e., long-standing pattern of behavior) but not for impulsivity when measured as a state (i.e., current risk for impulsive behavior). Furthermore, dopamine receptor levels did not significantly relate to reward sensitivity. In other words, the number and availability of dopamine receptors within the ventral striatum was not predictive of the extent to which these individuals were motivated by reward.
Having a family history of alcohol use disorder did not alter the general pattern of effects.
Despite earlier research suggesting an association, this study did not demonstrate a strong influence of family history of alcohol or other drug use disorder on the relationship between dopamine receptor availability and alcohol consumption or related factors. Also importantly, the findings showing no association between dopamine receptors and later hazardous drinking were similar both for individuals with and without a family history of substance use disorder.
WHAT ARE THE IMPLICATIONS OF THE STUDY FINDINGS?
The study examined 68 drinkers without a history of alcohol use disorder to test whether the dopamine receptor availability predicted later alcohol use 8 to 16 years later. Though no significant association was detected for this primary aim, small associations were observed between dopamine receptor and impulsivity, suggesting that this brain marker might predict traits associated with drinking problems like impulsivity though not alcohol use per se, particularly for individuals without alcohol use disorder.
These findings indicate that dopamine receptor availability can affect individuals differently, particularly concerning impulsivity. Understanding this individual variability is crucial when exploring how biological factors influence behavior. Moreover, the relationship between dopamine receptor availability and alcohol use appears to be complex, influenced by multiple factors beyond dopamine receptor levels. Regarding impulsivity, the study revealed that lower dopamine receptor availability correlated with heightened impulsivity, measured as a broader facet of impulsivity (i.e., “trait”) but not when measured as specific situational impulsivity (i.e., “state”). The study’s findings also challenge previous assumptions about dopamine receptor availability, hinting that it might function as a state-like marker that changes with alcohol use, rather than a stable trait-like predictor of alcohol-related behaviors. Family history of alcohol use disorder surprisingly did not influence the relationship between dopamine receptor availability and alcohol use or related factors. This unexpected result suggests further exploration into genetic influences beyond family history may be fruitful.
As we gain more insights into the link between dopamine receptor availability and impulsivity, personalized interventions targeting specific aspects of impulsivity in individuals with alcohol-related issues may become possible. In sum, this study adds greater nuance to our understanding of dopamine receptor availability’s role in alcohol-related behaviors and emphasizes the need for personalized and targeted approaches to study and address these issues.
The study had a moderately sized group for PET research, but it lacked diversity in terms of sex/gender, with only five females. This means the findings might not apply equally to men and women, emphasizing the need for more gender-balanced studies in the future.
The study did not report sample race/ethnicity so generalizability beyond White Swedish people is unknown.
The study included people ranging from 10 to 59 years old during their PET scans, which can complicate the relationship between dopamine receptor availability and age. The participant age range at the time of initial scanning, which included participants who were children, may have made it less likely to detect any effect between dopamine receptor level and later drinking. While the study made adjustments based on existing research, the wide age range makes it important to be cautious in interpreting the results. Future research might benefit from focusing on specific age groups.
Most participants reported drinking alcohol at levels below what is considered risky on measures of alcohol consumption, which reflects the study’s focus on individuals without a history of alcohol use disorder. However, it means the findings might not apply to people who have more serious alcohol issues. Future research should look at a wider range of alcohol consumption.
The study collected data on alcohol use and related factors during follow-up, not at the same time as the PET scans. This time gap makes it challenging to directly link striatal dopamine receptor availability and scores on measures of alcohol consumption at the time of the PET scans, introducing potential timing-related factors.
BOTTOM LINE
This quasi-longitudinal study of 68 participants found no relationship between dopamine receptor levels and future alcohol consumption, reward sensitivity, or family history, and only a modest-sized link to some impulsivity traits, all of which suggests that this brain marker may not be well-suited to predicting later hazardous drinking for those with no history of alcohol use disorder. While the study, given its design and limitations, does not necessarily suggest that dopamine receptor levels are linked to risk of lower risk drinking progressing to alcohol use disorder, the line of inquiry is worthy of future, more rigorous research to determine if other neurobiological factors may play a more substantive role.
For individuals and families seeking recovery: This study deepens our knowledge of how the brain is (and is not) involved in the development of alcohol use disorder, though the use of potential biomarkers to detect risk for future alcohol use disorder is in need of refinement, particularly in terms of linking such insights with managing the practical aspects of recovery, such as accessing various resources that enable individuals to begin and maintain recovery (i.e., recovery capital). Therefore, the utility of the findings from this study for individuals and families in recovery is limited.
For treatment professionals and treatment systems: Recovery encompasses a wide range of factors necessitating holistic and personalized treatment approaches. Although this research provides valuable insights into the neurobiological aspects of addiction, there is a need to better connect these insights with practical aspects of recovery, like accessing resources that support individuals in starting and sustaining their recovery journey, known as “recovery capital.” Consequently, the applicability of the study’s findings for treatment professionals and systems is somewhat limited.
For scientists: The limbic dopaminergic system has long been implicated in addiction. This somewhat rare prospective study adds to our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, and therefore holds significant value for scientists working in substance use disorder and neuroscience. These findings inform further research into refining our understanding of addiction mechanisms and developing more targeted interventions.
For policy makers: This study deepens our knowledge of how the brain’s neurocircuits and receptors may (and may not) be involved in the development of alcohol use disorder, yet its findings do not point to opportunities for direct policy actions. Policy makers might recognize the importance of multifaceted strategies to prevent and treat alcohol-related issues, particularly among high-risk populations. While this study offers insights into the brain’s role in addiction, it underscores the need for a comprehensive approach that considers a multitude of etiological pathways into alcohol use disorder. Effective policies and interventions should attend to the dynamic interaction of risk factors across bio-psycho-social levels to create a more impactful response to alcohol-related harms.
