Opioid use disorder is associated with a wide range of cognitive deficits and impairments. Studies suggest that opioid-related deficits may improve in some cognitive domains but not in others.
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Impulsivity and compulsivity are important factors in the addiction cycle, but it is not entirely understood how these cognitive functions and their associated brain structures look over the course of opioid addiction.
TWO IMPORTANT COGNITIVE DOMAINS IN ADDICTION & RECOVERY:
This study examined cognitive impulsivity, compulsivity, and brain structure, as well as relationships between them in individuals with opioid use disorder during periods of active addiction, methadone treatment, and abstinence-based recovery.
Four groups of men were recruited, including 3 patient groups diagnosed with opioid use disorder (determined with the Mini International Neuropsychiatric Interview) and 1 healthy control group.
Among those with opioid use disorder, 24 individuals were actively engaged in daily heroin use at the time of the study (heroin group; ~26 years old), 48 were in recovery and receiving methadone maintenance treatment (methadone treated group; ~30 years old; ~67 mg methadone per day for at least 6 months), and 24 were in recovery, no longer receiving methadone treatment, and free of all psychoactive substances for approximately 6 months (abstinent group; ~37 years old). The healthy control group consisted of 50 men (~28 years old) without a history of substance use disorder.
All participants provided information regarding their substance use histories and completed neuropsychological tests that examine various aspects of compulsivity and impulsivity. Compulsivity was investigated with the Intra-Extra Dimensional set-shifting task, which requires participants to learn task rules as they go and adapt their behavior as the rules of the task change (i.e. cognitive flexibility). Impulsivity was measured with the Cambridge Gambling Task for which participants make bets on their decisions in a game of probability/chance (i.e. decision making and risk-taking). A subset of the participants also completed brain scans, including 33 individuals in the methadone treated group, 15 in the abstinent group, and 23 in the healthy control group. Brain scans were performed with Magnetic Resonance Imaging (MRI) and structural brain images were assessed for probability of regional gray and white matter atrophy (reductions) by comparing opioid use disorder groups to the healthy control group.
None of the participants had a history of benzodiazepine, stimulant, or alcohol dependence, other significant psychiatric disorders (e.g., psychosis), or serious medical conditions (e.g., neurodevelopmental disorder). All patient groups had similar opioid use histories and demographic characteristics. Relative to the control group, the abstinent group was older and all three groups with opioid use disorder had lower premorbid IQ (baseline intellectual functioning). Only age-related differences persisted among the subgroups that completed brain scans.
In general, the abstinent group and heroin group performed similarly to one another on set-shifting task, with both showing higher levels of compulsivity than healthy controls. Worse performance on this specific task was related to reduced gray and white matter in a variety of cortical (at the brain’s surface) and subcortical (below the brain’s surface) regions. In the abstinent group poorer task performance was associated with reduced white matter in brain regions important for cognitive flexibility and adaptive responding (orbitofrontal and prefrontal cortex).
Impulsivity was impaired across all opioid use disorder groups relative to healthy controls. The heroin group showed the highest level of impulsivity and the methadone treated group showed the lowest degree of impulsivity, with the abstinent group fall in between. In the opioid use disorder group, lower levels of impulsivity were associated with higher levels of compulsivity. This compulsive/impulsive trade-off was related to structural brain abnormalities in the brain (prefrontal cortex & striatum) that control compulsivity and impulsivity.
Longer duration or histories of opioid misuse was associated with worse performance on both neuropsychological tasks (compulsivity & impulsivity) and with reduced gray matter in the globus pallidus, a region associated with heroin intoxication and impulsive behaviors.
Studies like these, that provide information about both brain and behavior, advance our understanding of recovery related processes and provide a more complete picture of the cognitive difficulties associated with substance use disorders, the brain abnormalities that underlie these behavioral deficits, and their potential to improve during treatment and recovery.
The results of this study revealed heightened compulsivity in individuals actively using heroin and in abstinent individuals recovering from opioid use disorder, suggesting that impaired cognitive flexibility (i.e. compulsive behaviors) may persist with short-term abstinence. Persistence of heightened compulsivity has the potential to increase risk of relapse.
Importantly, this study suggests that methadone may reduce compulsivity by normalizing dopamine and serotonin chemical imbalances in the brain, thereby alleviating compulsive tendencies. Furthermore, heightened compulsivity observed in abstinent individuals may suggest a recurrence of this chemical imbalance when ending methadone treatment.
The relationship between compulsivity and impulsivity suggests a dominant/subordinate relationship, in that impairments in impulsivity may become less pronounced as compulsive behaviors dominate, and vise-versa. This relationship speaks to theories of addiction that propose a dynamic shift from impulsivity dominating during the early stages of addiction to compulsivity dominating during the later stages. Nonetheless, impulsivity appears to be present to some degree at multiple stages of opioid addiction/recovery.
Opioid use disorder groups showed heightened impulsivity relative to control group participants. Cognitive impulsivity may be a risk factor that precedes opioid addiction and persists despite recovery from opioid use disorder or taking methadone. Adjunct therapies to enhance functioning (i.e. cognitive enhancement therapies) within this cognitive domain might help to prevent relapse.
Tolomeo, S., Matthews, K., Steele, D., & Baldacchino, A. (2018). Compulsivity in opioid dependence. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 81, 333-339.
l
Impulsivity and compulsivity are important factors in the addiction cycle, but it is not entirely understood how these cognitive functions and their associated brain structures look over the course of opioid addiction.
TWO IMPORTANT COGNITIVE DOMAINS IN ADDICTION & RECOVERY:
This study examined cognitive impulsivity, compulsivity, and brain structure, as well as relationships between them in individuals with opioid use disorder during periods of active addiction, methadone treatment, and abstinence-based recovery.
Four groups of men were recruited, including 3 patient groups diagnosed with opioid use disorder (determined with the Mini International Neuropsychiatric Interview) and 1 healthy control group.
Among those with opioid use disorder, 24 individuals were actively engaged in daily heroin use at the time of the study (heroin group; ~26 years old), 48 were in recovery and receiving methadone maintenance treatment (methadone treated group; ~30 years old; ~67 mg methadone per day for at least 6 months), and 24 were in recovery, no longer receiving methadone treatment, and free of all psychoactive substances for approximately 6 months (abstinent group; ~37 years old). The healthy control group consisted of 50 men (~28 years old) without a history of substance use disorder.
All participants provided information regarding their substance use histories and completed neuropsychological tests that examine various aspects of compulsivity and impulsivity. Compulsivity was investigated with the Intra-Extra Dimensional set-shifting task, which requires participants to learn task rules as they go and adapt their behavior as the rules of the task change (i.e. cognitive flexibility). Impulsivity was measured with the Cambridge Gambling Task for which participants make bets on their decisions in a game of probability/chance (i.e. decision making and risk-taking). A subset of the participants also completed brain scans, including 33 individuals in the methadone treated group, 15 in the abstinent group, and 23 in the healthy control group. Brain scans were performed with Magnetic Resonance Imaging (MRI) and structural brain images were assessed for probability of regional gray and white matter atrophy (reductions) by comparing opioid use disorder groups to the healthy control group.
None of the participants had a history of benzodiazepine, stimulant, or alcohol dependence, other significant psychiatric disorders (e.g., psychosis), or serious medical conditions (e.g., neurodevelopmental disorder). All patient groups had similar opioid use histories and demographic characteristics. Relative to the control group, the abstinent group was older and all three groups with opioid use disorder had lower premorbid IQ (baseline intellectual functioning). Only age-related differences persisted among the subgroups that completed brain scans.
In general, the abstinent group and heroin group performed similarly to one another on set-shifting task, with both showing higher levels of compulsivity than healthy controls. Worse performance on this specific task was related to reduced gray and white matter in a variety of cortical (at the brain’s surface) and subcortical (below the brain’s surface) regions. In the abstinent group poorer task performance was associated with reduced white matter in brain regions important for cognitive flexibility and adaptive responding (orbitofrontal and prefrontal cortex).
Impulsivity was impaired across all opioid use disorder groups relative to healthy controls. The heroin group showed the highest level of impulsivity and the methadone treated group showed the lowest degree of impulsivity, with the abstinent group fall in between. In the opioid use disorder group, lower levels of impulsivity were associated with higher levels of compulsivity. This compulsive/impulsive trade-off was related to structural brain abnormalities in the brain (prefrontal cortex & striatum) that control compulsivity and impulsivity.
Longer duration or histories of opioid misuse was associated with worse performance on both neuropsychological tasks (compulsivity & impulsivity) and with reduced gray matter in the globus pallidus, a region associated with heroin intoxication and impulsive behaviors.
Studies like these, that provide information about both brain and behavior, advance our understanding of recovery related processes and provide a more complete picture of the cognitive difficulties associated with substance use disorders, the brain abnormalities that underlie these behavioral deficits, and their potential to improve during treatment and recovery.
The results of this study revealed heightened compulsivity in individuals actively using heroin and in abstinent individuals recovering from opioid use disorder, suggesting that impaired cognitive flexibility (i.e. compulsive behaviors) may persist with short-term abstinence. Persistence of heightened compulsivity has the potential to increase risk of relapse.
Importantly, this study suggests that methadone may reduce compulsivity by normalizing dopamine and serotonin chemical imbalances in the brain, thereby alleviating compulsive tendencies. Furthermore, heightened compulsivity observed in abstinent individuals may suggest a recurrence of this chemical imbalance when ending methadone treatment.
The relationship between compulsivity and impulsivity suggests a dominant/subordinate relationship, in that impairments in impulsivity may become less pronounced as compulsive behaviors dominate, and vise-versa. This relationship speaks to theories of addiction that propose a dynamic shift from impulsivity dominating during the early stages of addiction to compulsivity dominating during the later stages. Nonetheless, impulsivity appears to be present to some degree at multiple stages of opioid addiction/recovery.
Opioid use disorder groups showed heightened impulsivity relative to control group participants. Cognitive impulsivity may be a risk factor that precedes opioid addiction and persists despite recovery from opioid use disorder or taking methadone. Adjunct therapies to enhance functioning (i.e. cognitive enhancement therapies) within this cognitive domain might help to prevent relapse.
Tolomeo, S., Matthews, K., Steele, D., & Baldacchino, A. (2018). Compulsivity in opioid dependence. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 81, 333-339.
l
Impulsivity and compulsivity are important factors in the addiction cycle, but it is not entirely understood how these cognitive functions and their associated brain structures look over the course of opioid addiction.
TWO IMPORTANT COGNITIVE DOMAINS IN ADDICTION & RECOVERY:
This study examined cognitive impulsivity, compulsivity, and brain structure, as well as relationships between them in individuals with opioid use disorder during periods of active addiction, methadone treatment, and abstinence-based recovery.
Four groups of men were recruited, including 3 patient groups diagnosed with opioid use disorder (determined with the Mini International Neuropsychiatric Interview) and 1 healthy control group.
Among those with opioid use disorder, 24 individuals were actively engaged in daily heroin use at the time of the study (heroin group; ~26 years old), 48 were in recovery and receiving methadone maintenance treatment (methadone treated group; ~30 years old; ~67 mg methadone per day for at least 6 months), and 24 were in recovery, no longer receiving methadone treatment, and free of all psychoactive substances for approximately 6 months (abstinent group; ~37 years old). The healthy control group consisted of 50 men (~28 years old) without a history of substance use disorder.
All participants provided information regarding their substance use histories and completed neuropsychological tests that examine various aspects of compulsivity and impulsivity. Compulsivity was investigated with the Intra-Extra Dimensional set-shifting task, which requires participants to learn task rules as they go and adapt their behavior as the rules of the task change (i.e. cognitive flexibility). Impulsivity was measured with the Cambridge Gambling Task for which participants make bets on their decisions in a game of probability/chance (i.e. decision making and risk-taking). A subset of the participants also completed brain scans, including 33 individuals in the methadone treated group, 15 in the abstinent group, and 23 in the healthy control group. Brain scans were performed with Magnetic Resonance Imaging (MRI) and structural brain images were assessed for probability of regional gray and white matter atrophy (reductions) by comparing opioid use disorder groups to the healthy control group.
None of the participants had a history of benzodiazepine, stimulant, or alcohol dependence, other significant psychiatric disorders (e.g., psychosis), or serious medical conditions (e.g., neurodevelopmental disorder). All patient groups had similar opioid use histories and demographic characteristics. Relative to the control group, the abstinent group was older and all three groups with opioid use disorder had lower premorbid IQ (baseline intellectual functioning). Only age-related differences persisted among the subgroups that completed brain scans.
In general, the abstinent group and heroin group performed similarly to one another on set-shifting task, with both showing higher levels of compulsivity than healthy controls. Worse performance on this specific task was related to reduced gray and white matter in a variety of cortical (at the brain’s surface) and subcortical (below the brain’s surface) regions. In the abstinent group poorer task performance was associated with reduced white matter in brain regions important for cognitive flexibility and adaptive responding (orbitofrontal and prefrontal cortex).
Impulsivity was impaired across all opioid use disorder groups relative to healthy controls. The heroin group showed the highest level of impulsivity and the methadone treated group showed the lowest degree of impulsivity, with the abstinent group fall in between. In the opioid use disorder group, lower levels of impulsivity were associated with higher levels of compulsivity. This compulsive/impulsive trade-off was related to structural brain abnormalities in the brain (prefrontal cortex & striatum) that control compulsivity and impulsivity.
Longer duration or histories of opioid misuse was associated with worse performance on both neuropsychological tasks (compulsivity & impulsivity) and with reduced gray matter in the globus pallidus, a region associated with heroin intoxication and impulsive behaviors.
Studies like these, that provide information about both brain and behavior, advance our understanding of recovery related processes and provide a more complete picture of the cognitive difficulties associated with substance use disorders, the brain abnormalities that underlie these behavioral deficits, and their potential to improve during treatment and recovery.
The results of this study revealed heightened compulsivity in individuals actively using heroin and in abstinent individuals recovering from opioid use disorder, suggesting that impaired cognitive flexibility (i.e. compulsive behaviors) may persist with short-term abstinence. Persistence of heightened compulsivity has the potential to increase risk of relapse.
Importantly, this study suggests that methadone may reduce compulsivity by normalizing dopamine and serotonin chemical imbalances in the brain, thereby alleviating compulsive tendencies. Furthermore, heightened compulsivity observed in abstinent individuals may suggest a recurrence of this chemical imbalance when ending methadone treatment.
The relationship between compulsivity and impulsivity suggests a dominant/subordinate relationship, in that impairments in impulsivity may become less pronounced as compulsive behaviors dominate, and vise-versa. This relationship speaks to theories of addiction that propose a dynamic shift from impulsivity dominating during the early stages of addiction to compulsivity dominating during the later stages. Nonetheless, impulsivity appears to be present to some degree at multiple stages of opioid addiction/recovery.
Opioid use disorder groups showed heightened impulsivity relative to control group participants. Cognitive impulsivity may be a risk factor that precedes opioid addiction and persists despite recovery from opioid use disorder or taking methadone. Adjunct therapies to enhance functioning (i.e. cognitive enhancement therapies) within this cognitive domain might help to prevent relapse.
Tolomeo, S., Matthews, K., Steele, D., & Baldacchino, A. (2018). Compulsivity in opioid dependence. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 81, 333-339.
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