Neuropsychological functioning in opiate-dependent subjects receiving and following methadone maintenance treatment

Cognitive control in opioid dependence and methadone maintenance treatment

BACKGROUND

Substance misuse is associated with cognitive dysfunction. We used a stop signal task to examine deficits in cognitive control in individuals with opioid dependence (OD). We examined how response inhibition and post-error slowing are compromised and whether methadone maintenance treatment (MMT), abstinence duration, and psychiatric comorbidity are related to these measures in individuals with OD.

METHODS

Two-hundred-and-sixty-four men with OD who were incarcerated at a detention center and abstinent for up to 2 months (n = 108) or at a correctional facility and abstinent for approximately 6 months (n = 156), 65 OD men under MMT at a psychiatric clinic, and 64 age and education matched healthy control (HC) participants were assessed. We computed the stop signal reaction time (SSRT) to index the capacity of response inhibition and post-error slowing (PES) to represent error-related behavioral adjustment, as in our previous work. We examined group effects with analyses of variance and covariance analyses, followed by planned comparisons. Specifically, we compared OD and HC participants to examine the effects of opioid dependence and MMT and compared OD sub-groups to examine the effects of abstinence duration and psychiatric comorbidity.

RESULTS

The SSRT was significantly prolonged in OD but not MMT individuals, as compared to HC. The extent of post-error slowing diminished in OD and MMT, as compared to HC (trend; p = 0.061), and there was no difference between the OD and MMT groups. Individuals in longer abstinence were no less impaired in these measures. Furthermore, these results remained when psychiatric comorbidities including misuse of other substances were accounted for.

CONCLUSIONS

Methadone treatment appears to be associated with relatively intact cognitive control in opioid dependent individuals. MMT may facilitate public health by augmenting cognitive control and thereby mitigating risky behaviors in heroin addicts.

Neurobehavioral consequences of chronic intrauterine opioid exposure in infants and preschool children: a systematic review and meta-analysis

BACKGROUND

It is assumed within the accumulated literature that children born of pregnant opioid dependent mothers have impaired neurobehavioral function as a consequence of chronic intrauterine opioid use.

METHODS

Quantitative and systematic review of the literature on the consequences of chronic maternal opioid use during pregnancy on neurobehavioral function of children was conducted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We searched Cinahl, EMBASE, PsychINFO and MEDLINE between the periods of January 1995 to January 2012.

RESULTS

There were only 5 studies out of the 200 identified that quantitatively reported on neurobehavioral function of children after maternal opioid use during pregnancy. All 5 were case control studies with the number of exposed subjects within the studies ranging from 33-143 and 45-85 for the controls. This meta-analysis showed no significant impairments, at a non-conservative significance level of p < 0.05, for cognitive, psychomotor or observed behavioural outcomes for chronic intra-uterine exposed infants and pre-school children compared to non-exposed infants and children. However, all domains suggested a trend to poor outcomes in infants/children of opioid using mothers. The magnitude of all possible effects was small according to Cohen's benchmark criteria.

CONCLUSIONS

Chronic intra-uterine opioid exposed infants and pre-school children experienced no significant impairment in neurobehavioral outcomes when compared to non-exposed peers, although in all domains there was a trend to poorer outcomes. The findings of this review are limited by the small number of studies analysed, the heterogenous populations and small numbers within the individual studies. Longitudinal studies are needed to determine if any neuropsychological impairments appear after the age of 5 years and to help investigate further the role of environmental risk factors on the effect of 'core' phenotypes.

A monoclonal antibody specific for 6-monoacetylmorphine reduces acute heroin effects in mice

Immunotherapy against drugs of abuse is being studied as an alternative treatment option in addiction medicine and is based on antibodies sequestering the drug in the bloodstream and blocking its entry into the brain. Producing an efficient vaccine against heroin has been considered particularly challenging because of the rapid metabolism of heroin to multiple psychoactive molecules. We have previously reported that heroin's first metabolite, 6-monoacetylmorphine (6-MAM), is the predominant mediator for heroin's acute behavioral effects and that heroin is metabolized to 6-MAM primarily prior to brain entry. On this basis, we hypothesized that antibody sequestration of 6-MAM is sufficient to impair heroin-induced effects and therefore examined the effects of a monoclonal antibody (mAb) specific for 6-MAM. In vitro experiments in human and rat blood revealed that the antibody was able to bind 6-MAM and block the metabolism to morphine almost completely, whereas the conversion of heroin to 6-MAM remained unaffected. Mice pretreated with the mAb toward 6-MAM displayed a reduction in heroin-induced locomotor activity that corresponded closely to the reduction in brain 6-MAM levels. Intraperitoneal and intravenous administration of the anti-6-MAM mAb gave equivalent protection against heroin effects, and the mAb was estimated to have a functional half-life of 8 to 9 days in mice. Our study implies that an antibody against 6-MAM is effective in counteracting heroin effects.

Hippocampal long-term potentiation is disrupted during expression and extinction but is restored after reinstatement of morphine place preference

Learned associations between environmental cues and morphine use play an important role in the maintenance and/or relapse of opioid addiction. Although previous studies suggest that context-dependent morphine treatment alters glutamatergic transmission and synaptic plasticity in the hippocampus, their role in morphine conditioned place preference (CPP) and reinstatement remains unknown. We investigated changes in synaptic plasticity and NMDAR expression in the hippocampus after the expression, extinction, and reinstatement of morphine CPP. Here we report that morphine CPP is associated with increased basal synaptic transmission, impaired hippocampal long-term potentiation (LTP), and increased synaptic expression of the NR1 and NR2b NMDAR subunits. Changes in synaptic plasticity, synaptic NR1 and NR2b expression, and morphine CPP were absent when morphine was not paired with a specific context. Furthermore, hippocampal LTP was impaired and synaptic NR2b expression was increased after extinction of morphine CPP, indicating that these alterations in plasticity may be involved in the mechanisms underlying the learning of drug-environment associations. After extinction of morphine CPP, a priming dose of morphine was sufficient to reinstate morphine CPP and was associated with LTP that was indistinguishable from saline control groups. In contrast, morphine CPP extinguished mice that received a saline priming dose did not show CPP and had disrupted hippocampal LTP. Finally, we found that reinstatement of morphine CPP was prevented by the selective blockade of the NR2b subunit in the hippocampus. Together, these data suggest that alterations in synaptic plasticity and glutamatergic transmission play an important role in the reinstatement of morphine CPP.

The role of cannabinoid transmission in emotional memory formation: implications for addiction and schizophrenia

Emerging evidence from both basic and clinical research demonstrates an important role for endocannabinoid (ECB) signaling in the processing of emotionally salient information, learning, and memory. Cannabinoid transmission within neural circuits involved in emotional processing has been shown to modulate the acquisition, recall, and extinction of emotionally salient memories and importantly, can strongly modulate the emotional salience of incoming sensory information. Two neural regions in particular, the medial prefrontal cortex (PFC) and the basolateral nucleus of the amygdala (BLA), play important roles in emotional regulation and contain high levels of cannabinoid receptors. Furthermore, both regions show profound abnormalities in neuropsychiatric disorders such as addiction and schizophrenia. Considerable evidence has demonstrated that cannabinoid transmission functionally interacts with dopamine (DA), a neurotransmitter system that is of exceptional importance for both addictive behaviors and the neuropsychopathology of disorders like schizophrenia. Research in our laboratory has focused on how cannabinoid transmission both within and extrinsic to the mesolimbic DA system, including the BLA → mPFC circuitry, can modulate both rewarding and aversive emotional information. In this review, we will summarize clinical and basic neuroscience research demonstrating the importance of cannabinoid signaling within this neural circuitry. In particular, evidence will be reviewed emphasizing the importance of cannabinoid signaling within the BLA → mPFC circuitry in the context of emotional salience processing, memory formation and memory-related plasticity. We propose that aberrant states of hyper or hypoactive ECB signaling within the amygdala-prefrontal cortical circuit may lead to dysregulation of mesocorticolimbic DA transmission controlling the processing of emotionally salient information. These disturbances may in turn lead to emotional processing, learning, and memory abnormalities related to various neuropsychiatric disorders, including addiction and schizophrenia-related psychoses.

Single and repeated ultra-rapid detoxification prevents cognitive impairment in morphine addicted rats: a privilege for single detoxification

BACKGROUND

Opioids have been shown to affect learning and memory processes. Different protocols of morphine withdrawal can substantially vary in their success to prevent opioid induced impairments of cognitive performance. In the present study, we report the effects of single and repetitive ultra-rapid detoxification (URD) on spatial learning and memory in morphine addicted rats.

METHODS

Morphine (10 mg/kg) was intraperitoneally (IP) injected in male rats once a day over one week and after which they were detoxified with naloxone administration under anesthesia. For the repetitive procedure, a second one week morphine treatment with a second subsequent detoxification was performed. Control groups received an equivalent volume of saline injections. Spatial learning and memory was evaluated using the Morris water maze (MWM) task.

FINDINGS

Both protocols of morphine administration resulted in a severe spatial memory impairment that could be significantly prevented by both single and repetitive URD. However, memory abilities in animals treated with repetitive URD were still significantly lower than in animals of the corresponding control group. Alterations in motor activity or sensory-motor coordination between morphine treated and control animals could be ruled out by comparing swimming speed and visible platform performances that were not different between groups. Thus, URD and, specifically single URD, can prevent the spatial memory impairments in addicted rats.

CONCLUSION

As opioid addiction is an extending and serious concern in many societies, these findings may have clinical values and therapeutic implications for patients who experience multiple opioid relapses.

Working memory and affective decision-making in addiction: a neurocognitive comparison between heroin addicts, pathological gamblers and healthy controls

BACKGROUND

Cognitive deficits are observed both in heroin dependence and in pathological gambling (PG) on various tasks. PG, as a non-substance addiction, is free of toxic consequences of drug use. Therefore a direct neurocognitive comparison of heroin addicts and pathological gamblers helps dissociate the consequences of chronic heroin use on cognitive function from the cognitive vulnerabilities that predispose addiction.

METHODS

A case-control design was used, comparing 58 abstinent heroin addicts, 58 pathological gamblers, and 60 healthy controls on working memory and affective decision-making functions. Working memory was assessed using the Self-ordered Pointing Test (SOPT). Affective decision-making was measured by the Iowa Gambling Task (IGT).

RESULTS

Heroin addicts performed significantly worse both on the IGT and on the SOPT, compared to healthy controls. Pathological gamblers performed worse on the IGT than healthy controls, but did not differ from controls on the SOPT. Years of heroin use were negatively correlated with working memory and affective decision-making performance in heroin addicts, while severity of gambling was not significantly correlated with any task performance in pathological gamblers.

CONCLUSIONS

Our findings indicate that deficits in affective decision-making shared by heroin dependence and PG putatively represent vulnerabilities to addiction and that working memory deficits detected only in heroin addicts may be identified as heroin-specific harmful effects.

Increased reflection impulsivity in patients with ephedrone-induced Parkinsonism

AIMS

To examine a syndrome of chronic manganism that occurs in drug addicts in eastern Europe who use intravenous methcathinone (ephedrone) contaminated with potassium permanganate. In many cases the basal ganglia, especially the globus pallidus and the putamen, are damaged irreversibly. Routine neuropsychological assessment has revealed no cognitive deficits, despite widespread abnormalities on brain imaging studies and severe extrapyramidal motor handicap on clinical examination.

DESIGN

Case-control study.

SETTING

Ephedrone patients and patients with opioid dependence were recruited from Lviv, Ukraine.

PARTICIPANTS

We tested 15 patients with ephedrone-induced toxicity, 13 opiate-dependent patients who were receiving opioid replacement therapy and 18 matched healthy volunteers.

MEASUREMENTS

The 'beads task', an information-gathering task to assess reflection impulsivity, was used and feedback learning, working memory and risk-taking were also assessed.

FINDINGS

Opiate-dependent patients differed from controls on three of four tasks, whereas ephedrone patients differed from controls on only one task. More specifically, both patient groups were more impulsive and made more irrational choices on the beads task than controls (P < 0.001). However, ephedrone patients had no deficits in working memory (P > 0.1) or risk-taking (P > 0.1) compared with controls. Opioid-dependent patients had significantly worse working memory (P < 0.001) and were significantly more risk-prone than controls (P = 0.002).

CONCLUSIONS

Ephedrone patients may have similar deficits in information-gathering and decision-making to opiate-dependent patients, with preservation of working memory and risk-taking. This may reflect specific damage to anterior cingulate- basal ganglia loops.

Autobiographical memory and differentiation of schematic models in substance-dependent patients

BACKGROUND AND OBJECTIVES

This study aims at investigating reduced autobiographical memory specificity in substance-dependent patients. We examined whether this phenomenon is related to undifferentiated schematic models of self and to depression and anxiety levels. We also investigated the maintenance of these impairments after early clinical remission.

METHODS

Seventy-three dependent patients (including 30 active users, 23 methadone-maintained patients, 20 early abstinent patients) and 31 control participants were given Williams' and Scott's Autobiographical Memory Test (AMT) to evaluate the level of memory specificity. Depression and anxiety levels were assessed with the Hospital Anxiety and Depression Scale (HADS), and the ability of differentiation in affect-related schematic models of self with the Level of Emotional Awareness Scale (LEAS).

RESULTS

Dependent patients recall less specific memories than control individuals to the AMT. For all the participants, only the ability to differentiate emotional states predicts the level of specificity, whereas reduced specificity is not linked to depression and anxiety levels. The results also show that reduced specificity is still observable in methadone-maintained patients and in abstinent patients.

LIMITATIONS

Despite the absence of difference in the level of memory specificity in the three groups of dependent patients, we cannot state that reduced memory specificity is stable over time because non-active consumers may not remain in remission for a long period.

CONCLUSIONS

Only a lack of emotional differentiation seems to impede the access to specific memories in dependent patients and in general population. The reduced memory specificity observed in dependent patients seems to last after recent clinical improvement.

Can patients receiving opioid maintenance therapy safely drive? A systematic review of epidemiological and experimental studies on driving ability with a focus on concomitant methadone or buprenorphine administration

OBJECTIVE

To perform a systematic review of the present scientific literature on the treatment with methadone or buprenorphine related to (1) traffic accident risk in epidemiological studies and (2) their effects on cognitive and psychomotor functions of relevance to driving in experimental studies.

METHODS

Searches for corresponding literature were conducted in MEDLINE, EMBASE, and PsycINFO throughout March and June of 2010. The search strategy consisted of words colligated to accident risk and culpability, in addition to cognitive and psychomotor functions of relevance to driving, all in relation to methadone or buprenorphine administration. In total, 59 studies were included.

RESULTS

Early epidemiological studies found no substantial difference in motor vehicle accident risk between methadone maintenance therapy patients (MMPs) and control groups. However, more recent studies have found an increased risk of traffic accident involvement for both MMPs and buprenorphine maintenance therapy patients (BMPs). In experimental studies, impairments of cognitive and psychomotor functions have been observed among both MMPs and BMPs when compared to control groups. When comparing MMPs with BMPs, the latter appeared to be less impaired than MMPs, but this difference may be unrelated to the maintenance therapy. Further impairments have been observed among MMPs after single doses, after an additional versus regular daily dosing, in multiple versus single dosing, and after long-term treatment compared to baseline levels. All studies showed impairments among opioid-naïve subjects after the administration of a comparatively low and single dose of either methadone or buprenorphine.

CONCLUSIONS

Both methadone and buprenorphine were confirmed as having impairing potentials in opioid-naïve subjects. At least some opioid maintenance therapy patients are observed having only slight impairments of relevance to driving. Knowing this when approaching the question of ability to drive, an individual evaluation of the driving performance, pertaining to the opioid maintained patient, may be the most useful and conclusive procedure.

Comparative patterns of cognitive performance amongst opioid maintenance patients, abstinent opioid users and non-opioid users

BACKGROUND

To compare the cognitive performances of maintenance patients (MAIN), abstinent ex-users (ABST) and healthy non-heroin using controls (CON).

METHODS

Case control study of 125 MAIN (94 subjects maintained on methadone, 31 on buprenorphine), 50 ABST and 50 CON. Neuropsychological tests measuring executive function, working memory, information processing speed, verbal learning and non-verbal learning were administered.

RESULTS

There were no differences between the cognitive profiles of those maintained on methadone or buprenorphine on any administered test. After controlling for confounders, the MAIN group had poorer performance than controls in six of the 13 administered tests, and were poorer than the ABST group in five. The MAIN group exhibited poorer performance in the Haylings Sentence Completion, Matrix Reasoning, Digit Symbol, Logical Memory (immediate and delayed recall), and the Complex Figure Test (immediate recall). There were no differences between the ABST and CON groups on any of the administered tests.

CONCLUSIONS

Poorer cognitive performance, across a range of test and domains, was seen amongst maintenance patients, regardless of their maintenance drug. This is a group that is likely might benefit from approaches for managing individuals with cognitive and behavioural difficulties arising from brain dysfunction.

Alpha-synuclein and heroin craving in opiate-dependent patients on injectable heroin maintenance

Research suggests that alpha-synuclein (SNCA) and NACP-Rep1, a polymorphic complex microsatellite repeat ~10 kb upstream of the SNCA gene translational start, may be involved in substance-use behaviors and craving. This study was the first to examine the effects of diacetylmorphine (DAM) on peripheral SNCA protein expression along with craving in opiate-dependent patients and to compare their NACP-Rep1 allele lengths with those of healthy controls. Using an experimental design, opiate-dependent patients on injectable heroin maintenance were investigated at four time points, twice pre- and post-injection of DAM. SNCA protein levels of 30 DAM-maintained patients were measured using enzyme-linked immunosorbent assay. Participant-rated effects were assessed in 42 patients by Tiffany's Heroin Craving Questionnaire (HCQ), Gossop's Short Opiate Withdrawal Scale and Visual Analogs. NACP-Rep1 alleles of 42 patients and 101 controls were analyzed. One-way repeated-measures ANOVAs provided significant overall effects for SNCA protein content (P = 0.028), craving (P < 0.001), withdrawal symptomatology (P < 0.001) and mood (P < 0.001), indicating that DAM injections may not only reduce craving but also SNCA protein expression. However, there was no association between protein expression and craving. Relative to controls, patients had significantly longer NACP-Rep1 alleles (P < 0.001). NACP-Rep1 allele lengths correlated positively with HCQ total scores averaged across all time points (r = 0.420; P = 0.006) as well as with post-DAM HCQ total scores in the morning (r = 0.488, P = 0.001) and afternoon (r = 0.423, P = 0.005). The findings provide evidence of a contributory role of SNCA and NACP-Rep1 for opiate dependence.

Semantic priming and verbal learning in current opiate users, ex-users and non-user controls

OBJECTIVE

Despite a growing interest in memory functions of chronic drug users, investigation of semantic and episodic memory in opiate users is limited, and findings of studies have been inconsistent. The present study aimed to assess semantic memory and episodic memory for both drug-related and neutral stimuli in current and ex-users of opiates.

METHODS

Using an independent group design, we assessed semantic priming and verbal learning in 16 current opiate users on a methadone maintenance programme, 16 ex-opiate users in rehabilitation programmes and 16 healthy controls. The groups were matched on verbal IQ, age and employment status.

RESULTS

We found that current and ex-users showed intact automatic and controlled semantic priming. Ex-users who had been abstinent for an average of 19 months showed a verbal learning impairment compared with controls. Both current and ex-users were impaired in recalling semantically unrelated words but unimpaired in recalling semantically related words.

CONCLUSION

The findings suggest a relative lack of spontaneous use of mnemonic strategies and imply that highly structured information would help opiate-using clients in treatment.

Response inhibition and psychomotor speed during methadone maintenance: impact of treatment duration, dose, and sleep deprivation

BACKGROUND

In opiate-dependent individuals, abstinence results in deficits in cognitive functioning, which may be exacerbated by medication-associated sleep disruption.

METHOD

To assess cognitive function and the influence of sleep deprivation (SD), 14 healthy control (HC) and 22 methadone maintained (MM) participants completed the continuous performance task (CPT) after a baseline night, a night of total SD, and two recovery sleep nights. The digit symbol substitution task (DSST) was administered at bedtime and in the morning. Secondary analyses separated MM participants into short- (< 12 months; n=8) and long-term (≥ 12 months; n=14) treatment duration groups, and into low- (< 80 mg; n=9) and high-dose (≥ 80 mg; n=13) groups.

RESULTS

Linear mixed model ANOVAs revealed that there was no effect of SD. Across all days MM participants had more errors of omission, fewer correct responses, and slower reaction times (RTs) on the CPT, and fewer accurate substitutions on the evening and morning DSST. Short-term MM participants exhibited slower RTs on the CPT, and fewer correct substitutions on the evening DSST compared to long-term MM participants. Low-dose MM participants had slower RTs on the CPT than HCs and high-dose MM participants.

CONCLUSION

These data demonstrate that methadone-maintained individuals exhibit poorer performance on tasks of psychomotor speed and selective attention/impulsivity, but with longer-term treatment, performance appears to return toward control levels. Furthermore, while one day of SD was enough to alter subjective reports of sleep quality, cognitive function may be more resilient.

The effects of acute and chronic steady state methadone on memory retrieval in rats

RATIONALE

Although widely prescribed to treat opioid addiction, little is known about the possible side effects of methadone on memory functions.

OBJECTIVES

The aim of this study is to compare the effects of acute and chronic methadone on memory retrieval in rats and to explore the selectivity of possible deficits.

METHODS

Administration of acute (0, 1.25, 2.5, and 5 mg/kg SC) and chronic steady state methadone (0, 10, 30, and 55 mg/kg/day SC by osmotic mini-pump) was tested on recall of three different types of information: stimulus-reward (10-arm parallel maze), stimulus-response (8-arm radial maze), and stimulus-stimulus (Barnes maze). Acute and steady state methadone doses were also compared on tests of locomotor activity and reactivity to aversive stimuli (i.e., swimming and acoustic startle).

RESULTS

In the stimulus-reward task, acute methadone impaired performance as a result of severe depression of locomotion. This motor deficit, however, was modulated by the motivational valence of environmental stimulation. In fact, acute methadone did not eliminate forced swimming behavior. In the stimulus-response and stimulus-stimulus tasks, accuracy was impaired independently of direct motor deficits, but rats were hyper-reactive to aversive stimulation and, in fact, 5 mg/kg enhanced acoustic startle. Importantly, chronic steady state methadone did not affect accuracy of memory retrieval, did not depress motor or swimming activity, and did not change startle reactivity.

CONCLUSION

Only acute methadone impaired accuracy and/or performance on three tests of memory retrieval. These findings in rats suggest that memory deficits reported in methadone-maintained individuals may not be directly attributable to methadone.

An increased risk of motor vehicle accidents after prescription of methadone

AIMS

To investigate whether exposure to methadone affects the risk of motor vehicle accident with personal injury.

DESIGN

Cohort study linking three Norwegian administrative registries using unique person identifiers.

SETTING

Information was retrieved from the Norwegian Prescription Database on any prescriptions ever received by the individuals for methadone and all prescriptions for benzodiazepines. The Norwegian Road Accident Registry provided information about motor vehicle accidents involving personal injuries on Norwegian roads. The Central Population Registry provided demographic information on all residents in Norway.

PARTICIPANTS

All Norwegian adults aged 18-69 years were observed for 2.5 years.

MEASUREMENTS

Standardized incidence ratio (SIR) was calculated by comparing the incidence of traffic accidents with personal injuries in patients exposed to methadone with the incidence in those not exposed.

FINDINGS

During the 4626 person-years observed in patients exposed to methadone, there were 26 motor vehicle accidents. There were very few accidents among the females who received methadone and they had no increased risk of being involved in motor vehicle accidents (SIR 1.1; 95% CI 0.2-3.1). We observed an increased risk of involvement in accidents among males (SIR 2.4; 95% CI 1.5-3.6). This figure did not change significantly when exposure to benzodiazepines was excluded.

CONCLUSIONS

Men exposed to methadone appear to have an increased risk of being involved in motor vehicle accidents involving personal injuries. This increased risk could not be explained by exposure of benzodiazepines.

White matter abnormalities correlating with memory and depression in heroin users under methadone maintenance treatment

Methadone maintenance treatment (MMT) has elevated rates of co-morbid memory deficit and depression that are associated with higher relapse rates for substance abuse. White matter (WM) disruption in MMT patients have been reported but their impact on these co-morbidities is unknown. This study aimed to investigate changes in WM integrity of MMT subjects using diffusion tensor image (DTI), and their relationship with history of heroin and methadone use in treated opiate-dependent individuals. The association between WM integrity changes from direct group comparisons and the severity of memory deficit and depression was also investigated. Differences in WM integrity between 35 MMT patients and 23 healthy controls were evaluated using DTI with tract-based spatial statistical analysis. Differences in DTI indices correlated with diminished memory function, Beck Depression Inventory, duration of heroin use and MMT, and dose of heroin and methadone administration. Changes in WM integrity were found in several WM regions, including the temporal and frontal lobes, pons, cerebellum, and cingulum bundles. The duration of MMT was associated with declining DTI indices in the superior longitudinal fasciculus and para-hippocampus. MMT patients had more memory and emotional deficits than healthy subjects. Worse scores in both depression and memory functions were associated with altered WM integrity in the superior longitudinal fasciculus, para-hippocampus, and middle cerebellar peduncle in MMT. Patients on MMT also had significant WM differences in the reward circuit and in depression- and memory-associated regions. Correlations among decreased DTI indices, disease severity, and accumulation effects of methadone suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities in MMT.

Structural deficits in the emotion circuit and cerebellum are associated with depression, anxiety and cognitive dysfunction in methadone maintenance patients: a voxel-based morphometric study

Heroin users on methadone maintenance treatment (MMT) have elevated rates of co-morbid depression and are associated with have higher relapse rates for substance abuse. Structural abnormalities in MMT patients have been reported, but their impact on clinical performance is unknown. We investigated differences in gray matter volume (GMV) between 27 MMT patients and 23 healthy controls with voxel-based morphometry, and we correlated findings in the patients with Beck Depression Inventory scores, Beck Anxiety Inventory scores, and diminished cognitive functioning. MMT patients exhibited higher emotional deficits than healthy subjects. There was significantly smaller GMV in multiple cortices, especially in the left inferior frontal gyrus and left cerebellar vermis in the MMT group. The smaller GMV in the pre-frontal cortices, left sub-callosal cingulate gyrus, left post-central gyrus, left insula, and right cerebellar declive correlated with higher depression scores. The smaller GMV in the pre-frontal cortices, left sub-callosal cingulate gyrus, and left postcentral gyrus also correlated with higher anxiety scores, while smaller GMV in the cerebellum and bilateral insula was associated with impaired performance on tests of executive function. These results reveal that MMT patients have low GMV in brain regions that are hypothesized to influence cognition and emotion, and the GMV findings might be involved comorbid disorders in the MMT group.

Long-term methadone treatment reduces phosphorylation of CaMKII in rat brain

Objectives

To reveal a possible relationship between a previously reported impairment of novelty seeking in rats exposed to methadone and changes in intracellular molecules related to learning and memory.

Methods

Expression of phosphorylated Ca2+-calmodulin kinase II (pCaMKII), extracellular-signal-regulated kinase 2 (pERK2) and cAMP-responsive element binding protein (pCREB), as well as protein kinase A (PKA), was investigated in rat hippocampus one hour, one day and one week after a three-week methadone administration regime. Studies after an equivalent exposure to morphine, and in the frontal pole, were included for comparison.

Key findings

One day after the last methadone injection the hippocampal level of pCaMKII was significantly reduced. This coincides with a previously reported impairment of novelty seeking. At one hour and one week no significant changes were seen. There was no effect on the other proteins. Morphine affected pCaMKII similarly to methadone. Also in the frontal pole the two drugs reduced pCaMKII one day after the last injection.

Conclusion

The impaired novelty seeking previously found in rats administered methadone for three weeks coincides with a reduced level of pCaMKII in the brain. This finding implies that methadone treatment may affect learning and memory processes, and should stimulate further studies in a field with important knowledge gaps.

Factors affecting cognitive function of opiate-dependent patients

BACKGROUND

A wide range of studies found that opiate-dependent patients suffer from cognitive impairment due to a number of different factors. However, this issue has never been examined systematically. Thus, the aim of the present study is to provide a comprehensive analysis of factors that might contribute to cognitive impairment of opiate-dependent patients and specifically differentiates between various cognitive abilities as these might be impacted differently.

METHODS

Based on a comprehensive review of the literature with regard to previous findings and suggestions about which factors might affect cognitive functioning, we assessed a wide variety of variables related to substance use and opiate-dependence as well as demographic and socioeconomic variables. Cognitive functioning was assessed through a neuropsychological test-battery.

RESULTS

We found that the duration of opiate dependence and maintenance treatment, as well as additional substance consumption (alcohol, amphetamines, and cocaine) are the main variables contributing to cognitive impairment in the domains of attention and executive function. Comorbid depressive symptoms negatively affected reaction times. There was no evidence for the role of demographic variables like age and education on cognitive functioning.

CONCLUSIONS

Our findings suggest that it might be important in the treatment of opiate dependence to address the consumption of additional substances and to closely monitor the negative effects of maintenance treatment on cognitive functioning.

White matter microstructure in opiate addiction

Heroin addiction has been associated with impaired neuronal connectivity and cognitive deficits. One mechanism that potentially explains these findings is alterations in white matter connectivity secondary to chronic opiate use. However, few studies have quantitavely examined white matter deficits in opiate addiction (OA). Here, we investigated white matter microstructure in OA using diffusion tensor imaging (DTI). We performed voxel-wise analysis of fractional anisotropy (FA) in 24 participants with OA and 29 healthy controls. The OA group showed reduced FA in multiple pathways including the corpus callosum, thalamic radiation and inferior longitudinal fasciculus. This FA reduction was mainly the result of increased radial diffusivity (λ(⊥)), indicative of myelin pathology. Longer duration of OA was also associated with axonal diffusivity (λ(1)), most robustly in superior longitudinal fasciculi and right frontal white matter suggesting axonal injury in long-term users. Together, the findings indicate that chronic OA use has widespread and diverse effects on neuronal connectivity and function.

Cognitive functioning in opioid-dependent patients treated with buprenorphine, methadone, and other psychoactive medications: stability and correlates

BACKGROUND

In many but not in all neuropsychological studies buprenorphine-treated opioid-dependent patients have shown fewer cognitive deficits than patients treated with methadone. In order to examine if hypothesized cognitive advantage of buprenorphine in relation to methadone is seen in clinical patients we did a neuropsychological follow-up study in unselected sample of buprenorphine- vs. methadone-treated patients.

METHODS

In part I of the study fourteen buprenorphine-treated and 12 methadone-treated patients were tested by cognitive tests within two months (T1), 6-9 months (T2), and 12-17 months (T3) from the start of opioid substitution treatment. Fourteen healthy controls were examined at similar intervals. Benzodiazepine and other psychoactive comedications were common among the patients. Test results were analyzed with repeated measures analysis of variance and planned contrasts. In part II of the study the patient sample was extended to include 36 patients at T2 and T3. Correlations between cognitive functioning and medication, substance abuse, or demographic variables were then analyzed.

RESULTS

In part I methadone patients were inferior to healthy controls tests in all tests measuring attention, working memory, or verbal memory. Buprenorphine patients were inferior to healthy controls in the first working memory task, the Paced Auditory Serial Addition Task and verbal memory. In the second working memory task, the Letter-Number Sequencing, their performance improved between T2 and T3. In part II only group membership (buprenorphine vs. methadone) correlated significantly with attention performance and improvement in the Letter-Number Sequencing. High frequency of substance abuse in the past month was associated with poor performance in the Letter-Number Sequencing.

CONCLUSIONS

The results underline the differences between non-randomized and randomized studies comparing cognitive performance in opioid substitution treated patients (fewer deficits in buprenorphine patients vs. no difference between buprenorphine and methadone patients, respectively). Possible reasons for this are discussed.

A comparison of cognitive function in patients under maintenance treatment with heroin, methadone, or buprenorphine and healthy controls: an open pilot study

INTRODUCTION

Cognitive impairment has been reported in drug-dependent patients under opioid maintenance treatment.

OBJECTIVES

To compare cognitive functioning in healthy controls and in opioid-dependent patients treated with Buprenorphine, Heroin, or methadone maintenance.

METHODS

We used the standardized test battery ART-90 to study cognitive function in patients under long-term heroin treatment (n = 20), Bup (n = 22), or Met (n = 24) maintenance treatment and healthy controls (n = 25).

RESULTS

Patients receiving heroin performed significantly worse than healthy controls in most domains. Heroin patients performed worse than patients in the other two treatment groups in subtests measuring psychomotor performance under stress conditions and monotony.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

Although a number of limitations must be taken into account, this study provides some preliminary evidence that cognitive function may be more impaired in patients under heroin maintenance treatment than in patients receiving Bup or Met and in healthy controls.

The World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for the biological treatment of substance use and related disorders. Part 2: Opioid dependence

OBJECTIVES

To develop evidence-based practice guidelines for the pharmacological treatment of opioid abuse and dependence.

METHODS

An international task force of the World Federation of Societies of Biological Psychiatry (WFSBP) developed these practice guidelines after a systematic review of the available evidence pertaining to the treatment of opioid dependence. On the basis of the evidence, the Task Force reached a consensus on practice recommendations, which are intended to be clinically and scientifically meaningful for physicians who treat adults with opioid dependence. The data used to develop these guidelines were extracted primarily from national treatment guidelines for opioid use disorders, as well as from meta-analyses, reviews, and publications of randomized clinical trials on the efficacy of pharmacological and other biological treatments for these disorders. Publications were identified by searching the MEDLINE database and the Cochrane Library. The literature was evaluated with respect to the strength of evidence for efficacy, which was categorized into one of six levels (A-F).

RESULTS

There is an excellent evidence base supporting the efficacy of methadone and buprenorphine or the combination of buprenorphine and naloxone for the treatment of opioid withdrawal, with clonidine and lofexidine as secondary or adjunctive medications. Opioid maintenance with methadone and buprenorphine is the best-studied and most effective treatment for opioid dependence, with heroin and naltrexone as second-line medications.

CONCLUSIONS

There is enough high quality data to formulate evidence-based guidelines for the treatment of opioid abuse and dependence. This task force report provides evidence for the efficacy of a number of medications to treat opioid abuse and dependence, particularly the opioid agonists methadone or buprenorphine. These medications have great relevance for clinical practice.

Long-term methadone treatment impairs novelty preference in rats both when present and absent in brain tissue

Behavioral consequences of long-term methadone treatment have received little attention either in humans or experimental animals. In this work, we show that methadone (2.5-10 mg/kg) administered (sc) once daily for three weeks with repeated withdrawal on Saturday and Sunday impairs the novelty preference in rats. One hour after the last injection, when methadone was still present in brain tissue, the rats were too affected by the sedative effects of the drug to perform the test. This was confirmed by an almost total lack of locomotor activity or exploratory behavior. One day after the last injection, the methadone treated rats showed a 70% reduction (p < 0.05) in novelty preference compared to rats administered saline. No methadone was detected in the brain tissue at this time. Moreover, there were no differences in locomotor activity or total exploratory behavior between the groups, indicating a specific impairment of cognitive functioning. In brain tissue, the methadone concentration versus time profile was shifted to the left after long-term treatment, indicating a change in uptake and distribution of the drug. The area under the two concentration versus time curves was, however, similar. Methadone disappeared completely from the brain within one day. Together, these results suggest that long-term methadone treatment may have a negative impact on cognitive functioning in rats, regardless of whether methadone is present in brain tissue.

Contributors to neuropsychological impairment in HIV-infected and HIV-uninfected opiate-dependent patients

Neuropsychological (NP) impairment is multiply determined among HIV-infected and HIV-uninfected individuals who are also dually diagnosed with depression and who use illicit substances. The purpose of the present study was to assess the impact of HIV status, depression, and problematic substance use on NP performance. A total of 160 opiate-dependent outpatients undergoing methadone maintenance (80 HIV-infected, 80 HIV-uninfected) completed diagnostic and NP evaluations. Raw scores from individual NP tests were converted to Z scores relative to standard norms and were averaged to form a composite score. HIV-infected participants had significantly lower overall NP performance--as well as lower performance on tests of attention, motor speed, and verbal memory--than HIV-uninfected participants. In multiple regression analyses considering the role of depression and substance use, only HIV status emerged as a significant predictor of NP impairment. These findings confirm NP impairment in HIV-infected substance abusing patients independent of comorbid depression and severity of substance use.

Investigating the relationship between sexual and chemical addictions by comparing executive function in subjects with pedophilia or opiate addiction and healthy controls

Disorders of driven sexual behavior have been conceptualized as sexual addictions. In the following study, we compared 51 subjects with pedophilia, 53 subjects with opiate addiction, and 84 healthy control subjects on neuropsychological tests that tap executive functions. The test battery included the Wisconsin Card Sorting Test (WCST), Stroop Color-Word Test, the Matching Familiar Figures Test (MFFT), Porteus Mazes, Controlled Word Association (COWA), and Trailmaking Test. The groups differed on tests of cognitive flexibility and set switching (WCST), sustained attention (Stroop), and impulsivity (MFFT and Porteus Mazes). There were no differences on verbal fluency (COWA). The subjects with pedophilia differed significantly from those with opiate addiction on several tests, with longer latency to response on MFFT and fewer completed mazes but also fewer errors on Porteus Mazes. Thus, while both subjects with pedophilia and those with opiate addiction show executive dysfunction, the nature of that dysfunction may differ between the two groups; specifically, opiate addicted subjects may be more prone to cognitive impulsivity.

Adapting problem-solving therapy for depressed older adults in methadone maintenance treatment

Late-life depression is prevalent in older adults who are dependent on opiates. Depressive disorders among opiate abusers have detrimental effects on their well-being and ability to refrain from illegal drugs. There are numerous barriers to the provision of appropriate mental health care to older adults receiving methadone maintenance treatment. This article focuses on problem-solving therapy (PST) and presents evidence that PST may be a promising nonpharmacological treatment for older methadone clients with comorbid depressive disorders that can be applied within the staffing and resource limits of methadone maintenance treatment facilities. The advantages of PST relative to other behavioral therapies for this population are based on evidence that PST is less cognitively demanding for an older adult population with mood and substance use disorders. A properly modified PST for an older adult substance-dependent population with subsyndromal or diagnosed depression may be a viable option for methadone maintenance programs with limited resources.

Methadone disposition in oral fluid during pharmacotherapy for opioid-dependence

INTRODUCTION

Oral fluid testing is widely used for detecting drug exposure, but data describing methadone and metabolites in oral fluid during pharmacotherapy for opioid-dependence are relatively limited.

METHODS

414 oral fluid specimens from 16 opioid-dependent pregnant women receiving daily methadone were analyzed for methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and methadol by liquid chromatography-mass spectrometry.

RESULTS

All oral fluid specimens contained methadone greater than 1 ng/mL; 88% were positive for EDDP and 12% for methadol. Over 95% of oral fluid specimens exceeded the 20 ng/mL methadone cutoff set by the European Driving Under the Influence of Drugs, Alcohol and Medicines (DRUID) study. Methadone and EDDP oral fluid concentrations were highly variable within and between participants, did not predict methadone dose, but were negatively correlated with pH.

CONCLUSION

Methadone was readily identified in oral fluid at concentrations greater than 20 ng/mL following daily 30-110 mg/day methadone pharmacotherapy. As no specimens contained only EDDP or methadol, there was no advantage to including these analytes for identification of methadone exposure. As nearly all oral fluid specimens from methadone-maintained patients exceeded the DRUID guideline, the 20 ng/mL cutoff appears to be sensitive enough to detect daily methadone exposure; however, additional indicators of behavioral and/or motor impairment would be necessary to provide evidence of driving impairment.

Substance use and women's health

Scientific findings show that substance abuse in women yields a higher risk of a variety of health problems than substance abuse in men. Research suggests that women experience addiction telescoping when they abuse alcohol, tobacco, specific stimulants, and possibly opioids. Medical side effects also develop more rapidly in women than men when they abuse many substances. Cancer and cardiac complications, specifically, pose a significant threat for women who abuse almost all types of substances. However, the physical consequences are not the only ones women suffer when they engage in substance abuse. Research on substance abuse in women ties opioids to mood and anxiety disorders, heroin to neurological deficiencies, cocaine to immune system suppression, and alcohol to intimate partner abuse. Additionally, female substance abusers, on average, have a lower level of education and lower rates of employment. In light of these gender-specific concerns, physicians should give particular consideration to detecting substance abuse in women.

Sustained attention in patients receiving and abstinent following methadone maintenance treatment for opiate dependence: performance and neuroimaging results

OBJECTIVE

Impairments in the function of attention exacerbate the course of opiate dependence and may play a role in the relapsing nature of the disorder. This study used clinical measures and positron emission tomography (PET) to assess the functioning of sustained attention in subjects with a history of opiate dependence.

METHODS

A test of auditory sustained attention was administered to 10 subjects receiving methadone maintenance treatment, 13 formerly opiate-dependent subjects in protracted abstinence, and 14 healthy Comparison subjects. Simultaneous measurement of regional glucose metabolism was made by [(18)F] flourodeoxyglucose PET. Subjects groups were compared on the measures of sustained attention and regional cerebral glucose metabolism.

RESULTS

Healthy Comparison subjects scored significantly better than either methadone-maintained or abstinent former opiate addicts on measures of sustained attention. Formerly opiate-dependent subjects in protracted abstinence scored better than methadone-maintained subjects on sustained attention. Methadone-maintained subjects demonstrated a relative reduction in regional cerebral glucose metabolism in the right supramarginal gyrus, and the thalamus bilaterally. The Comparison subjects without a history of opiate dependence demonstrated a relative increase in regional cerebral glucose metabolism in the right anterior cingulate gyrus, the right medial superior frontal gyrus and the thalamus bilaterally.

CONCLUSIONS

Subjects with a history of opiate dependence have impairments in the functioning of sustained attention, and abnormalities in brain regions identified as important in attention processing. Impairments in attention performance persist in subjects who enjoy prolonged abstinence from opiates.

Neuropsychological functioning in buprenorphine maintained patients versus abstinent heroin abusers on naltrexone hydrochloride therapy

RATIONALE

Methadone and buprenorphine are among the most widely employed pharmacological treatments currently available for opioid addiction. Cognitive effects of buprenorphine in abstinent heroin abusers are nevertheless far from being understood.

METHODS

Neuropsychological performance of 18 buprenorphine-maintained patients (BMP) was evaluated relative to that of 32 currently abstinent heroin abusers on naltrexone hydrochloride therapy (FHAN), and 34 non-drug dependent controls. The three groups were demographically balanced. Clinical groups reported histories of similar patterns of drug use and had increased periods of abstinence from any illicit substance use including heroin.

RESULTS

The BMP group performed poorer than controls on the RAVLT (encoding and delayed recall of verbal information), CTT (conceptual flexibility, executive functions) and the RBANS figure copy (visual perception) and delayed recall of visual information. There were no significant differences in any of the cognitive measures between the BMP and FHAN groups or between the FHAN group and controls. Furthermore, the non-differing percentage of abnormal cases between the two patient groups led us to infer that treatment with either BPM or FHAN is not accompanied by qualitative differences in the cognitive profiles of these patients.

CONCLUSION

Overall, results suggest that treatment with naltrexone in abstinent heroin abusers may result in less impairment of cognitive functions compared to treatment with buprenorphine. These findings are relevant for improved prognosis and treatment strategies in opioid dependence.

Gray matter density negatively correlates with duration of heroin use in young lifetime heroin-dependent individuals

Numerous studies have documented cognitive impairments and hypoactivity in the prefrontal and anterior cingulate cortices in drug users. However, the relationships between opiate dependence and brain structure changes in heroin users are largely unknown. In the present study, we measured the density of gray matter (DGM) with voxel-based morphometry in 30 lifetime heroin-dependent individuals who had abstained from drug use for 5 months, and 34 healthy participants. The DGM of the prefrontal, temporal and cingulate cortices significantly decreased in heroin addicts relative to the healthy group. Critically, partial correlation analysis, which controlled for age, education and gender factors as well as nicotine use and heroin abstinence duration, showed that the duration of heroin use negatively correlated with the DGM in heroin-dependent individuals. These results provide compelling evidence for structural abnormality in heroin-dependent individuals and further suggest that duration of heroin use is a critical factor leading to brain damage.

The impact of neuropsychological functioning on adherence to HAART in HIV-infected substance abuse patients

This study assessed the frequency of neuropsychological impairment and its relationship to adherence in a sample of HIV-infected injection drug users (IDUs) in treatment. One hundred eight participants recruited between September 2006 and October 2008 completed psychodiagnostic and neuropsychological assessments and monitored HAART adherence over a 2-week period via the use of Medication Event Monitoring System (MEMS) electronic pill caps and self-report. Assessment of concurrent functioning included clinician-rated scales of depression and substance use severity, and a battery of neuropsychological tests. Findings from individual neuropsychological tests were converted to Z scores relative to standard norms and averaged to form a composite score (NPZ). NPZ was generally poor (mean = -1.505, standard deviation = 1.120), with 76.9% of the sample being classified as highly impaired. Self-reported adherence was significantly higher than MEMS cap adherence. In contrast with previous studies, overall neuropsychological functioning was not a significant predictor of electronically monitored or self-reported adherence. However, examiner-rated current global severity of substance use and delayed word list recall emerged as significant predictors of self-reported adherence. Additionally, estimated premorbid verbal intelligence emerged as a significant predictor of the discrepancy between electronically monitored and self-reported adherence. Given the extent of neuropsychological impairment in this sample, future studies should examine the degree to which the impact of neuropsychological impairment may moderate interventions for this population, and the extent to which skills to cope with neuropsychological problems may boost the potential efficacy of such interventions.

Intrauterine cocaine exposure and executive functioning in middle childhood

This longitudinal study evaluated whether the level of intrauterine cocaine exposure (IUCE) or the interaction between IUCE and contextual variables was related during middle childhood to executive functioning, as assessed with the Stroop Color-Word and Rey Osterrieth Complex Figure tests. The Stroop Interference score measures verbal inhibitory control while the Rey Osterrieth Organizational score evaluates skills such as planning, organization and perception. Masked examiners assessed 143 children at 9.5 and 11 years of age (74 with IUCE and 69 demographically similar children without IUCE). Level of IUCE (Unexposed; Lighter, and Heavier) was documented by positive postpartum maternal reports and infant meconium assays. In covariate-controlled regressions, level of IUCE was not significantly associated with Stroop Interference or Rey Osterrieth Organization scores. However, in covariate controlled post-hoc tests comparing the Heavier exposed group to the combined Lighter/Unexposed group, children in the Heavier group had significantly poorer Stroop Interference scores, but there was no significant group difference for Rey Osterrieth Organizational scores. Children's average Organization scores in Unexposed, Lighter, and Heavier exposed groups were well below the test norm means. Results of this study indicate that heavier IUCE may be associated with mild compromise on school-aged children's ability to inhibit prepotent verbal responses.

Methadone and impairment in apprehended drivers

AIMS

According to Norwegian guidelines, patients who are in opioid-assisted rehabilitation programmes are permitted to drive a motor vehicle provided that certain requirements are met. The purpose of this study was to investigate apprehended drivers who had methadone in their blood at the time of apprehension and, further, the relationship between blood methadone concentration and impairment as measured by the clinical test of impairment (CTI).

METHODS

The division of Forensic Toxicology and Drug Abuse (DFTDA) at the Norwegian Institute of Public Heath analyses blood samples from all drivers suspected of driving under the influence of drugs nation-wide. Cases with positive results for methadone in blood were collected over the period 2001-2006.

RESULTS

A total of 635 drivers with methadone found in their blood samples were identified. The majority of drivers were men (>80%), aged between 30 and 40 years. Methadone was the only psychoactive drug detected in blood in only 10 cases. Benzodiazepines were a frequent finding (in approximately 90% of cases). A significant difference in blood methadone concentration was found between cases where only methadone was detected [median 0.46 mg/l (range 0.19-0.65)] and cases where methadone was detected in combination with other psychoactive drugs [median 0.28 mg/l (range 0.06-1.24)]. A CTI had been carried out, in conjunction with blood sampling, in 577 of the cases. A concentration-impairment relationship was not seen for methadone in these cases.

CONCLUSIONS

Cases of driving impairment involving methadone alone were very rare, with combination use most frequent. No correlation between methadone concentration and impairment as judged by the CTI was seen either for these cases or for the material as a whole.

Character pathology and neuropsychological test performance in remitted opiate dependence

Background

Cognitive deficits and personality pathology are prevalent in opiate dependence, even during periods of remission, and likely contribute to relapse. Understanding the relationship between the two in vulnerable, opiate-addicted patients may contribute to the design of better treatment and relapse prevention strategies.

Methods

The Millon Multiaxial Clinical Inventory (MCMI) and a series of neuropsychological tests were administered to three subject groups: 29 subjects receiving methadone maintenance treatment (MM), 27 subjects in protracted abstinence from methadone maintenance treatment (PA), and 29 healthy non-dependent comparison subjects. Relationships between MCMI scores, neuropsychological test results, and measures of substance use and treatment were examined using bivariate correlation and regression analysis.

Results

MCMI scores were greater in subjects with a history of opiate dependence than in comparison subjects. A significant negative correlation between MCMI scores and neuropsychological test performance was identified in all subjects. MCMI scores were stronger predictors of neuropsychological test performance than measures of drug use.

Conclusion

Formerly methadone-treated opiate dependent individuals in protracted opiate abstinence demonstrate a strong relationship between personality pathology and cognitive deficits. The cause of these deficits is unclear and most likely multi-factorial. This finding may be important in understanding and interpreting neuropsychological testing deficiencies in opiate-dependent subjects.

Comparison of personality traits in pedophiles, abstinent opiate addicts, and healthy controls: considering pedophilia as an addictive behavior

To investigate the model of pedophilia as a disorder of addictive behavior, pedophiles and chemically addicted individuals were compared on personality traits potentially associated with impaired behavioral inhibition. Twenty-nine pedophiles, 25 opiate addicts (OA's), and 27 healthy controls were administered the Barratt Impulsivity Scale, Hare Psychopathy Checklist-Revised (PCL-R), and Structured Clinical Interview for DSM-V for Axis-II. OA's scored higher than either pedophiles or controls on the Barratt. Pedophiles and OA's scored higher than controls on all 3 Psychopathy Checklist-Revised scores but OA's scored marginally higher than pedophiles on factor 2 (behavioral) and total scores. On Structured Clinical Interview for DSM-V for Axis-II, pedophiles scored higher than controls on paranoid and schizoid scores whereas OA's did so on paranoid scores. Thus, both pedophiles and OA's may have elevated psychopathic traits and propensity toward cognitive distortions, as reflected in cluster A traits. Such similarities support the conceptualization of pedophilia as a behavioral addiction. Pedophiles may be less impulsive than OA's, however, and more prone toward cognitive distortions.

Regulatory Issues Encountered when Conducting Longitudinal Substance Abuse Research

OBJECTIVE: To summarize challenges unique to obtaining Institutional Review Board (IRB) approval for longitudinal substance abuse research, focusing on solutions and lessons learned. METHODS: Thirteen senior Principal Investigators with experience conducting research on substance abuse treatment and health services outcomes recalled instances from the prior 5 years when obtaining UCLA and non-UCLA IRB approval was hampered by differences in the interpretation of regulatory guidelines and how those differences were resolved. PRINCIPAL FINDINGS: Comprehensive yet flexible research protocols regarding (1) informed and voluntary consent, (2) participant payment, and (3) re-contact efforts are essential for securing IRB approval of longitudinal substance abuse studies. Specific examples of lessons learned are provided. CONCLUSIONS: Experiences can help researchers to provide appropriate and explicit justification for longitudinal substance abuse research protocols, thereby minimizing the burden and cost associated with meeting regulatory requirements as well as enhancing the efficiency, quantity, and quality of data collected.

Predictors of decision-making on the Iowa Gambling Task: independent effects of lifetime history of substance use disorders and performance on the Trail Making Test

Poor decision-making and executive function deficits are frequently observed in individuals with substance use disorders (SUDs), and executive deficits may contribute to poor decision-making in this population. This study examined the influence of lifetime history of an alcohol, cocaine, heroin, or polysubstance use disorder on decision-making as measured by the Iowa Gambling Task (IGT) after controlling for executive ability, demographic characteristics, and current substance use. Participants (131 with lifetime history of SUD and 37 controls) completed the IGT and two neuropsychological tests: the Trail Making Test and the Controlled Oral Word Association Test. Control participants performed significantly better than those with a lifetime SUD history on the IGT, but performance on the neuropsychological tests was comparable for the two groups. A lifetime SUD diagnosis was associated with performance on the IGT after controlling for covariates, and Trail Making Test performance was associated with IGT performance in both SUD and control participants.

Auditory target processing in methadone substituted opiate addicts: the effect of nicotine in controls

BACKGROUND

The P300 component of the auditory evoked potential is an indicator of attention dependent target processing. Only a few studies have assessed cognitive function in substituted opiate addicts by means of evoked potential recordings. In addition, P300 data suggest that chronic nicotine use reduces P300 amplitudes. While nicotine and opiate effects combine in addicted subjects, here we investigated the P300 component of the auditory event related potential in methadone substituted opiate addicts with and without concomitant non-opioid drug use in comparison to a group of control subjects with and without nicotine consumption.

METHODS

We assessed 47 opiate addicted out-patients under current methadone substitution and 65 control subjects matched for age and gender in an 2-stimulus auditory oddball paradigm. Patients were grouped for those with and without additional non-opioid drug use and controls were grouped for current nicotine use. P300 amplitude and latency data were analyzed at electrodes Fz, Cz and Pz.

RESULTS

Patients and controls did not differ with regard to P300 amplitudes and latencies when whole groups were compared. Subgroup analyses revealed significantly reduced P300 amplitudes in controls with nicotine use when compared to those without. P300 amplitudes of methadone substituted opiate addicts were in between the two control groups and did not differ with regard to additional non-opioid use. Controls with nicotine had lower P300 amplitudes when compared to patients with concomitant non-opioid drugs. No P300 latency effects were found.

CONCLUSION

Attention dependent target processing as indexed by the P300 component amplitudes and latencies is not reduced in methadone substituted opiate addicts when compared to controls. The effect of nicotine on P300 amplitudes in healthy subjects exceeds the effects of long term opioid addiction under methadone substitution.