Orbitofrontal Dysfunction and Medication Overuse in Patients With Migraine

Altered functional brain network patterns in patients with migraine without aura after transcutaneous auricular vagus nerve stimulation

Transcutaneous auricular vagus nerve stimulation (taVNS) shows excellent effects on relieving clinical symptoms in migraine patients. Nevertheless, the neurological mechanisms of taVNS for migraineurs remain unclear. In recent years, voxel-wise degree centrality (DC) and functional connectivity (FC) methods were extensively utilized for exploring alterations in patterns of FC in the resting-state brain. In the present study, thirty-five migraine patients without aura and thirty-eight healthy controls (HCs) were recruited for magnetic resonance imaging scans. Firstly, this study used voxel-wise DC analysis to explore brain regions where abnormalities were present in migraine patients. Secondly, for elucidating neurological mechanisms underlying taVNS in migraine, seed-based resting-state functional connectivity analysis was employed to the taVNS treatment group. Finally, correlation analysis was performed to explore the relationship between alterations in neurological mechanisms and clinical symptoms. Our findings indicated that migraineurs have lower DC values in the inferior temporal gyrus (ITG) and paracentral lobule than in healthy controls (HCs). In addition, migraineurs have higher DC values in the cerebellar lobule VIII and the fusiform gyrus than HCs. Moreover, after taVNS treatment (post-taVNS), patients displayed increased FC between the ITG with the inferior parietal lobule (IPL), orbitofrontal gyrus, angular gyrus, and posterior cingulate gyrus than before taVNS treatment (pre-taVNS). Besides, the post-taVNS patients showed decreased FC between the cerebellar lobule VIII with the supplementary motor area and postcentral gyrus compared with the pre-taVNS patients. The changed FC of ITG-IPL was significantly related to changes in headache intensity. Our study suggested that migraine patients without aura have altered brain connectivity patterns in several hub regions involving multisensory integration, pain perception, and cognitive function. More importantly, taVNS modulated the default mode network and the vestibular cortical network related to the dysfunctions in migraineurs. This paper provides a new perspective on the potential neurological mechanisms and therapeutic targets of taVNS for treating migraine.

Decision-making impairment under ambiguity but not under risk may underlie medication overuse in patients with chronic migraine

OBJECTIVE

To explore whether patients with chronic migraine and medication overuse headache (CM + MOH) present with decision-making deficit.

BACKGROUND

Factors underlying MOH in patients with CM remain unclear. Whether the process of decision-making plays a role in MOH is still controversial. Decision-making varies in the degree of uncertainty: under ambiguity where the probability of outcome is unknown, and under risk where probabilities are known.

METHODS

Decisions under ambiguity and risk were assessed with the Iowa Gambling Task and the Cambridge Gambling Task, respectively, whereas executive function was assessed by the Wisconsin Card Sorting Test.

RESULTS

A total of 75 participants: 25 patients with CM + MOH, 25 with CM, and 25 age- and sex-similar healthy controls (HCs), completed this cross-sectional study. There was no significant difference in headache profiles except for more frequent analgesic use (mean ± SD: 23.5 ± 7.6 vs. 6.8 ± 3.4 days; p < 0.001) and higher Severity of Dependence Scores (median [25th-75th percentile]: 8 [5-11] vs. 1 [0-4]; p < 0.001) in patients with CM + MOH compared to CM. Total net score (mean ± SD) on the Iowa Gambling Task in patients with CM + MOH, CM, and HCs were - 8.1 ± 28.7, 10.9 ± 29.6, and 14.2 ± 28.8, respectively. There was a significant difference between the three groups (F(2, 72)  = 4.28, p = 0.017), with patients with CM + MOH making significantly more disadvantageous decisions than patients with CM (p = 0.024) and HCs (p = 0.008), while the CM and HC groups did not differ (p = 0.690). By contrast, there was no significant difference between the groups in the Cambridge Gambling Task and the Wisconsin Card Sorting Test. Furthermore, performance on the Iowa Gambling Task was inversely correlated with analgesic consumption (r = -0.41, p = 0.003), suggesting that decision-making under ambiguity may be related to MOH.

CONCLUSIONS

Our data suggest that patients with CM + MOH had impaired decisions under ambiguous, but not risky situations. This dissociation indicates disrupted emotional feedback processing rather than executive dysfunction, which may underlie the pathogenesis of MOH.

Medication overuse headache and substance use disorder: A comparison based on basic research and neuroimaging

It has yet to be determined whether medication overuse headache (MOH) is an independent disorder or a combination of primary headache and substance addiction. To further explore the causes of MOH, we compared MOH with substance use disorder (SUD) in terms of the brain regions involved to draw more targeted conclusions. In this review, we selected alcohol use disorder (AUD) as a representative SUD and compared MOH and AUD from two aspects of neuroimaging and basic research. We found that in neuroimaging studies, there were many overlaps between AUD and MOH in the reward circuit, but the extensive cerebral cortex damage in AUD was more serious than that in MOH. This difference was considered to reflect the sensitivity of the cortex structure to alcohol damage. In future research, we will focus on the central amygdala (CeA), prefrontal cortex (PFC), orbital-frontal cortex (OFC), hippocampus, and other brain regions for interventions, which may have unexpected benefits for addiction and headache symptoms in MOH patients.

Validity of the Severity of Dependence Scale for detecting dependence behaviours in chronic migraine with medication overuse

AIMS

In this study, we tested the validity of the Severity of Dependence Scale in detecting dependence behaviours in patients with chronic migraine and medication overuse (CM + MO) using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and the Leeds Dependence Questionnaire as gold standard measures.

METHODS

Four hundred and fifty-four patients with CM + MO filled in the Severity of Dependence Scale and the Leeds Dependence Questionnaire and underwent a psychological evaluation for the diagnosis of substance dependence according to the DSM-IV criteria.

RESULTS

Sixty-nine percent of subjects (n = 313) presented substance dependence according to the DSM-IV criteria. These patients scored significantly higher than those without substance dependence in Severity of Dependence Scale total score (Z = -3.29, p = 0.001), and in items 1 (Z = -2.44, p = 0.015), 2 (Z = -2.50, p = 0.012), 4 (Z = -2.05, p = 0.04), and 5 (Z = -3.39, p = 0.001). Severity of Dependence Scale total score (β = 0.13, SE = 0.04, z = 3.49, p < 0.001) was a significant predictor for substance dependence. Receiver Operating Characteristic (ROC) curves showed that Severity of Dependence Scale discriminated patients with or without substance dependence.

CONCLUSION

Severity of Dependence Scale could represent an interesting screening tool for dependency-like behaviors in CM + MO patients.

Differences in Frontal Lobe Dysfunction in Patients with Episodic and Chronic Migraine

Neuroimaging and neuropsychological investigations have indicated that migraineurs exhibit frontal lobe-related cognitive impairment. We investigated whether orbitofrontal and dorsolateral functioning differed between individuals with episodic migraine (EM) and chronic migraine (CM), focusing on orbitofrontal dysfunction because it is implicated in migraine chronification and medication overuse headache (MOH) in migraineurs. This cross-sectional study recruited women with CM with/without MOH (CM + MOH, CM − MOH), EM, and control participants who were matched in terms of age and education. We conducted neuropsychological assessments of frontal lobe function via the Trail Making Test (TMT) A and B, the Wisconsin Card Sorting Test (WCST), and the Iowa Gambling Task (IGT). We enrolled 36 CM (19 CM + MOH, 17 CM − MOH), 30 EM, and 30 control participants. The CM patients performed significantly (p < 0.01) worse on the TMT A and B than the EM patients and the control participants. The WCST also revealed significant differences, with poorer performance in the CM patients versus the EM patients and the control participants. However, the net scores on the IGT did not significantly differ among the three groups. Our findings suggest that the CM patients exhibited frontal lobe dysfunction, and, particularly, dorsolateral dysfunction. However, we found no differences in frontal lobe function according to the presence or absence of MOH.

Brain Metabolism and Structure in Chronic Migraine

PURPOSE OF REVIEW

The purpose of this paper is to review and synthesize current literature in which neurochemical and structural brain imaging were used to investigate chronic migraine (CM) pathophysiology and to further discuss the clinical implications.

RECENT FINDINGS

Spectroscopic and structural MRI studies have shown the presence of both impaired metabolism and structural alterations in the brain of CM patients. Metabolic changes in key brain regions support the notion of altered energetics and homeostasis as part of CM pathophysiology. Furthermore, CM, like other chronic pain disorders, may undergo structural reorganization in pain-related brain regions following near persistent endogenous painful input. Finally, both imaging techniques may provide potential biomarkers of disease state and progression and may help guide novel therapeutic interventions or strategies. Spectroscopic and structural MRI have revealed novel aspects of CM pathophysiology. Findings from the former support the metabolic theory of migraine pathogenesis.

Severity of Analgesic Dependence and Medication-overuse Headache

BACKGROUND AND AIMS

Medication-overuse headache (MOH) is a common chronic headache caused by overuse of headache analgesics. It has similarities with substance dependence disorders. The treatment of choice for MOH is withdrawal of the offending analgesics. Behavioral brief intervention treatment using methods adapted from substance misuse settings is effective. Here we investigate the severity of analgesics dependence in MOH using the Severity of Dependence Scale (SDS), validate the SDS score against formal substance dependence diagnosis based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) and examine whether the SDS predicts successful withdrawal.

METHODS

Representative recruitment from the general population; 60 MOH patients, 15 chronic headache patients without medication overuse and 25 population controls. Headaches were diagnosed using the International Classification of Headache Disorders, medication use was assessed and substance dependence classified according to the DSM-IV. The SDS was scored by interviewers blinded to patient group. Descriptive statistics were used and validity of the SDS score assessed against a substance dependence diagnosis using ROC analysis.

RESULTS

Sixty-two percent of MOH patients overused simple analgesics, 38% centrally acting analgesics (codeine, opiates, triptans). Fifty percent of MOH patients were classified as DSM-IV substance dependent. Centrally active medication and high SDS scores were associated with higher proportions of dependence. ROC analysis showed SDS scores accurately identified dependence (area under curve 88%). Lower SDS scores were associated with successful withdrawal (P = 0.004).

CONCLUSIONS

MOH has characteristics of substance dependence which should be taken into account when choosing treatment strategy.

TRIAL REGISTRATION

Based on data collected in previously reported randomized BIMOH trial (; in the present manuscript, Clinical trials registration number: NCT01314768). The present part, however, represents observational data and is not a treatment trial.

Clinical and biobehavioral perspectives: Is medication overuse headache a behavior of dependence?

Medication overuse headache (MOH), previously known as analgesic abuse headache or medication misuse headaches, is a common form of chronic headache disorder that has a detrimental impact on health and society. Although it has been widely accepted that overusing abortive medications is paradoxically the cause of MOH and drug discontinuation is the treatment of choice, ongoing debates exist as to whether drug consumption per se is the cause or consequence of headache chronification. Certain features in MOH such as their compulsive drug-seeking behavior, withdrawal headaches and high relapse rates share similarities with drug dependence, suggesting that there might be common underlying biological and psychobehavioral mechanisms. In this regard, this article will discuss the updated evidence and current debates on the possible biobehavioral overlap between MOH and drug dependence. To begin with, we will discuss whether MOH has characteristics of substance dependence based on standard psychiatry diagnostic criteria and other widely used dependence scales. Recent epidemiological studies underscoring common psychiatric comorbidities between the two disorders will also be presented. Although both demonstrate seemingly distinct personality traits, recent studies revealed similar decision-making impairment from a cognitive perspective, indicating the presence of a maladaptive reward system in both disorders. In addition, emerging imaging studies also support this notion by showing reversible morphological and functional brain changes related to the mesocorticolimbic reward circuitry in MOH, with a strong resemblance to those in addiction. Finally, an increased familial risk for drug dependence and genetic association with dopaminergic and drug dependence molecular pathways in MOH also support a possible link between MOH and addiction. Understanding the role of dependence in MOH will have a great impact on disease management as this will provide the missing piece of the puzzle in current therapeutic strategies.

Impact of dissociative experiences in migraine and its close relationship with osmophobia

OBJECTIVE

Migraine is a complex episodic disease manifested by dysfunction of the sympathetic nervous system along with numerous neuropsychiatric symptoms. The aim of this study was to identify the dissociative symptoms with neurobiological similarities in episodic and chronic migraine patients and to evaluate their correlation with migraine frequency and severity of attacks.

METHODS

The study included 61 episodic, 45 chronic migraine patients diagnosed using the criteria of the International Headache Society and 54 healthy control subjects. Dissociative Experiences Scale, Beck Anxiety Scale and Beck Depression Inventory were filled with the interviews. Demographic, clinical and headache characteristics of the patients were recorded according to migraine types. Results were analyzed by Kruskal-Wallis method and Spearman's correlation tests.

RESULTS

Dissociative symptoms were more common in the patients with chronic migraine, and there was a statistically significant difference between the chronic migraine group and the episodic migraine and control groups (p = 0.001, p < 0.001). Dissociative experiences were correlated with depression and anxiety findings, and in both groups, there was a significant correlation between clinical characteristics of migraine and osmophobia in the controlled partial correlation analysis (p < 0.05).

CONCLUSION

This study revealed that dissociative symptoms are more common especially in patients with chronic migraine and there is a significant association with osmophobia in both migraine groups. According to these data, we think that dissociative symptoms in chronic migraine patients will be questioned and osmophobia may be a guide in this regard.

Volume of Hypothalamus as a Diagnostic Biomarker of Chronic Migraine

It is believed than hypothalamus (HTH) might be involved in generation of migraine, and evidence from high resolution fMRI reported that the more anterior part of HTH seemed to play an important role in migraine chronification. The current study was aimed to identify the alteration of morphology and resting-state functional connectivity (FC) of the hypothalamus (HTH) in interictal episodic migraine (EM) and chronic migraine (CM). High-resolution structural and resting-state functional magnetic resonance images were acquired in 18 EM patients, 16 CM patients, and 21 normal controls (NC). The volume of HTH was calculated and voxel-based morphometry (VBM) was performed over the whole HTH. Receiver operating characteristics (ROC) curve analysis was applied to evaluate the diagnostic efficacy of HTH volume. Correlation analyses with clinical variables were performed and FC maps were generated for positive HTH regions according to VBM comparison. The volume of the HTH significantly decreased in both EM and CM patients compared with NC. The cut-off volume of HTH as 1.429 ml had a good diagnostic accuracy for CM with sensitivity of 81.25% and specificity of 100%. VBM analyses identified volume reduction of posterior HTH in EM vs. NC which was negatively correlated with headache frequency. The posterior HTH presented decreased FC with the left inferior temporal gyrus (Brodmann area 20) in EM. Decreased volume of anterior HTH was identified in CM vs. NC and CM vs. EM which was positively correlated with headache frequency in CM. The anterior HTH presented increased FC with the right anterior orbital gyrus (AOrG) (Brodmann area 11) in CM compared with NC and increased FC with the right medial orbital gyrus (MOrG) (Brodmann area 11) in CM compared with EM. Our study provided evidence of structural plasticity and FC changes of HTH in the pathogensis of migraine generation and chronification, supporting potential therapeutic target toward the HTH and its peptide.

Illness perception in people with primary and secondary chronic headache in the general population

BACKGROUND

Chronic headache (headache ≥15 days/month) is a leading cause of disability. Illness perception, beliefs and cognitive models are likely central for patient understanding of their chronic pain condition and are associated with treatment outcome. However, these factors are insufficiently described in chronic headache.

OBJECTIVE

To describe illness perception, and to explore the effect of background variables and headache characteristics on illness perceptions in primary and secondary chronic headaches in the general population.

METHODS

30,000 persons aged 3044 from the general population were screened for chronic headache by a mailed questionnaire. Those with self-reported chronic headache were interviewed by headache specialists. The questionnaire response rate was 71%, and the interview participation rate was 74%. The International Classification of Headache Disorders III was applied. Illness perception was assessed by the Revised Illness Perception Questionnaire (IPQ-R). The statistical approach was exploratory.

RESULTS

405 of the 516 eligible participants (78%) completed the IPQ-R. Confirmatory factor analysis showed good internal validity in chronic headache. People believed their chronic headache to be long-lasting, with negative life consequences including emotional distress. Severe headache-related disability was associated with more perception of chronicity, more perceived consequences, emotional load and illness identity and less illness coherence. People with secondary chronic headache scored significantly higher on chronicity and life consequences, and had less personal control than those with primary chronic headache.

CONCLUSION

Chronic primary and secondary headache is associated with a high symptom burden and chronicity with large perceived negative consequences for daily living, suggesting multidisciplinary management may be necessary.

The effect of acute pain on risky and intertemporal choice

Pain is a highly salient and attention-demanding experience that motivates people to act. We investigated the effect of pain on decision making by delivering acute thermal pain to participants' forearm while they made risky and intertemporal choices involving money. Participants (n = 107) were more risk seeking under pain than in a no-pain control condition when decisions involved gains but not when they involved equivalent losses. Pain also resulted in greater preference for immediate (smaller) over future (larger) monetary rewards. We interpret these results as a motivation to offset the aversive, pain-induced state, where monetary rewards become more appealing under pain than under no pain and when delivered sooner rather than later. Our findings add to the long-standing debate regarding the role of intuition and reflection in decision making.

[Chronic pain : Perception, reward and neural processing]

Many chronic pain syndromes are characterized by enhanced perception of painful stimuli as well as alterations in cortical processing in sensory and motor regions. In this review article the alterations in muscle pain and neuropathic pain are described. Alterations in patients with fibromyalgia and chronic back pain are described as examples for musculoskeletal pain and also in patients with phantom limb pain after amputation and complex regional pain syndrome as examples for neuropathic pain. In addition to altered pain perception, cumulative evidence on alterations in the processing of reward and the underlying mechanisms in chronic pain has been described. A description is given of what is known on how pain and reward interact and affect each other. The relevance of such interactions for chronic pain is discussed. The implications of these findings for therapeutic approaches are delineated with respect to sensorimotor training and behavioral therapy, focusing on the effectiveness of these approaches, mechanisms and future developments. In particular, we discuss operant behavioral therapy in patients with chronic back pain and fibromyalgia as well as prosthesis training in patients with phantom limb pain and discrimination, mirror and imaginary training in patients with phantom limb pain and complex regional pain syndrome. With respect to the processing of reward, the focus of the discussion is on the role of reward and associated learning in pain therapy.

Gray matter changes related to medication overuse in patients with chronic migraine

Objective

The objective of this article is to investigate the neurological substrates associated with medication overuse (MO) in patients with chronic migraine (CM).

Methods

We recruited age- and sex-matched CM patients with MO (CMwMO), CM patients without MO (CMwoMO), and healthy controls (HCs). Magnetic resonance T1-weighted images were processed by voxel-based morphometry, and the findings were correlated with clinical variables and treatment responses.

Results

A total of 66 patients with CM (half with MO) and 33 HCs completed the study. Patients with CMwMO compared to the patients with CMwoMO showed gray matter volume (GMV) decrease in the orbitofrontal cortex and left middle occipital gyrus as well as GMV increase in the left temporal pole/parahippocampus. The GMV changes explained 31.1% variance of the analgesics use frequency. The patients who responded to treatment had greater GMV in the orbitofrontal cortex ( p = 0.028). Patients with CM (with and without MO), compared with HCs, had decreased GMV at multiple brain areas including the frontal, temporal and occipital lobes, precuneus and cerebellum.

Conclusions

Our study showed GMV changes in CMwMO patients compared to the CMwoMO patients. These three cerebral regions accounted for significant variance in analgesics use frequency. Moreover, the GMV of the orbitofrontal cortex was predictive of the response to MO treatments.

Nucleus accumbens functional connectivity discriminates medication-overuse headache

Medication-overuse headache (MOH) is a secondary form of headache related to the overuse of triptans, analgesics and other acute headache medications. It is believed that MOH and substance addiction share some similar pathophysiological mechanisms. In this study we examined the whole brain resting state functional connectivity of the dorsal and ventral striatum in 30 patients (15 MOH and 15 non-MOH patients) to investigate if classification algorithms can successfully discriminate between MOH and non-MOH patients on the basis of the spatial pattern of resting state functional connectivity of the dorsal and ventral striatal region of interest. Our results indicated that both nucleus accumbens and dorsal rostral putamen functional connectivity could discriminate between MOH and non-MOH patients, thereby providing possible support to two interpretations. First, that MOH patients show altered reward functionality in line with drug abusers (alterations in functional connectivity of the nucleus accumbens). Second, that MOH patients show inability to break habitual behavior (alterations in functional connectivity of the dorsal striatum). In conclusion, our data showed that MOH patients were characterized by an altered functional connectivity of motivational circuits at rest. These differences could permit the blind discrimination between the two conditions using classification algorithms. Considered overall, our findings might contribute to the development of novel diagnostic measures.

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Nucleus accumbens functional connectivity could discriminate between MOH and non-MOH patients.

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Dorsal rostral putamen functional connectivity could also discriminate between MOH and non-MOH patients.

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Our data provide insights on possible pathophysiological mechanisms of medication abuse.

Cognition and emotional decision-making in chronic low back pain: an ERPs study during Iowa gambling task

Previous reports documented abnormalities in cognitive functions and decision-making (DM) in patients with chronic pain, but these changes are not consistent across studies. Reasons for these discordant findings might include the presence of confounders, variability in chronic pain conditions, and the use of different cognitive tests. The present study was aimed to add evidence in this field, by exploring the cognitive profile of a specific type of chronic pain, i.e., chronic low back pain (cLBP). Twenty four cLBP patients and 24 healthy controls underwent a neuropsychological battery and we focused on emotional DM abilities by means of Iowa gambling task (IGT). During IGT, behavioral responses and the electroencephalogram (EEG) were recorded in 12 patients and 12 controls. Event-related potentials (ERPs) were averaged offline from EEG epochs locked to the feedback presentation (4000 ms duration, from 2000 ms before to 2000 ms after the feedback onset) separately for wins and losses and the feedback-related negativity (FRN) and P300 peak-to-peak amplitudes were calculated. Among cognitive measures, cLBP patients scored lower than controls in the modified card sorting test (MCST) and the score in this test was significantly influenced by pain duration and intensity. Behavioral IGT results documented worse performance and the absence of a learning process during the test in cLBP patients compared to controls, with no effect of pain characteristics. ERPs findings documented abnormal feedback processing in patients during IGT. cLBP patients showed poor performance in the MCST and the IGT. Abnormal feedback processing may be secondary to impingement of chronic pain in brain areas involved in DM or suggest the presence of a predisposing factor related to pain chronification. These abnormalities might contribute to the impairment in the work and family settings that often cLBP patients report.

Dependency-like behaviors and pain coping styles in subjects with chronic migraine and medication overuse: results from a 1-year follow-up study

Background

Even after successful detoxification, 20-40% of subjects presenting chronic migraine with symptomatic medication overuse (CMwMO) relapse into medication overuse within one year. In this restrospective analysis on subjects referred to our center for detoxification, we investigated whether personality traits, dependency-like behaviors and pain coping styles predicted those who relapsed into medication overuse within the 12 months following the detoxification and those who did not.

Methods

63 patients with CMwMO were assessed for personality traits, mood and anxiety, pain coping styles and dependency-like behaviors prior-to and one year after a detoxification program.

Results

Of the 42 subjects who attended 1-year follow-up interviews, 11 relapsed into medication overuse despite a temporary benefit from detoxification and did not show clinical or psychological improvement, instead reporting increased anxiety and unmodified perpetuation of severe dependency-like behaviors. In contrast, subjects who did not relapse into medication overuse had clinical improvements that generalized to untreated domains, including decreased depressive symptoms and dependency-like behaviors, although showing unmodified low internal control over pain.

Conclusions

Subjects who did not fall into medication overuse throughout the 12 months following the detoxification showed improved clinical, affective and dependence-related outcomes, but not pain coping strategies. Conversely, subjects who relapsed within one year into CMwMO continued to experience significant disability, pain intensity, and dependency-like behaviors. We believe that the persistence of maladaptive pain coping strategies and residual symptomatology increase the risk for recurrent relapses, against which pharmacological interventions are only partially effective. Further studies investigating predictors of relapse are needed to inform multi-disciplinary interventions for CMwMO.

Combined effect of common gene variants on response to drug withdrawal therapy in medication overuse headache

PURPOSE

No information is currently available on genetic determinants of short-term response to drug withdrawal in medication overuse headache (MOH). In the present study, we aimed to evaluate the role of 14 polymorphisms in 8 candidate genes potentially relevant for drug addiction (OPRM1, DRD2, DBH, COMT, BDNF, SLC6A4, 5HT2A, and SLC1A2) as predictors for detoxification outcome of MOH patients at 2 months of follow-up.

METHODS

Genotyping was conducted by PCR, PCR-RFLP analysis, or real-time PCR allelic discrimination assay on genomic DNA extracted from peripheral blood. The association between gene variants and risk of unsuccessful detoxification was evaluated by univariate and multivariate logistic regression analyses.

RESULTS

One hundred and eight MOH patients with effective drug withdrawal therapy and 65 MOH patients with unsuccessful detoxification were available for the analysis. In the multivariable logistic regression analysis, triptan overuse (odds ratio (OR) 0.271, 95% confidence interval (CI) 0.083-0.890, P = 0.031) and TT genotype carriage of DRD2 NcoI (OR 0.115, 95% CI 0.014-0.982, P = 0.048) emerged as independent predictors for unsuccessful detoxification. In addition, carriers of at least four of the six top-ranked gene variants (P < 0.10) were found at higher odds for unsuccessful detoxification than patients with ≤3 high-risk genotypes (OR 3.40, 95% CI 1.65-7.01, P = 0.001).

CONCLUSION

This exploratory study suggests that DRD2 NcoI may be a genetic determinant of detoxification outcome in MOH patients. Our findings also show that an approach based on the combination of multiple genetic markers could be clinically useful for identification of MOH patients at higher risk for unsuccessful detoxification.

Understanding the relationship between pain and emotion in idiopathic headaches

The aim of this paper is to review hypotheses regarding pain mechanisms in headache and relationships between headache pain and the brain's emotional network. There is evidence that chronic pain in idiopathic headaches is, in part, an emotional response induced by alterations in the homeostasis of the interoceptive system--a system that integrates nociceptive information with the emotional network (mediating emotional awareness). These findings suggest that idiopathic headaches are probably due to both an altered pain matrix on the one hand, and an altered affective-cognitive state on the other.

Brain functional connectivity and morphology changes in medication-overuse headache: Clue for dependence-related processes?

BACKGROUND

Several imaging studies have identified localized anatomical and functional brain changes in medication-overuse headache (MOH).

OBJECTIVE

The objective of this article is to evaluate whole-brain functional connectivity at rest together with voxel-based morphometry in MOH patients, in comparison with episodic migraine (EM) patients and healthy controls (HCs).

METHODS

Anatomical MRI and resting-state functional MRI scans were obtained in MOH patients (n = 17 and 9, respectively), EM patients (n = 18 and 15, respectively) and HCs (n = 17 and 17). SPM8 was used to analyze voxel-based morphometry and seed (left precuneus) to voxel connectivity data in the whole brain.

RESULTS

Functional connectivity at rest was altered in MOH patients. Connectivity was decreased between precuneus and regions of the default-mode network (frontal and parietal cortices), but increased between precuneus and hippocampal/temporal areas. These functional modifications were not accompanied by significant gross morphological changes. Furthermore, connectivity between precuneus and frontal areas in MOH was negatively correlated with migraine duration and positively correlated with self-evaluation of medication dependence. Gray matter volumes of frontal regions, precuneus and hippocampus were also negatively related to migraine duration. Functional connectivity within the default-mode network appeared to predict anxiety scores of MOH patients while gray matter volumes in this network predicted their depression scores.

CONCLUSIONS

Our data suggest that MOH is associated with functional alterations within intrinsic brain networks rather than with macrostructural changes. They also support the view that dependence-related processes might play a prominent role in its development and maintenance.

Psychiatric screening for migraine patients

Psychiatric disorders in migraine patients have a higher prevalence than general population. The presence of psychiatric comorbidities may influence the complexity of the migraine pictures and be related to medication overuse. Severely impaired chronic migraineurs presenting with medication overuse are a challenge for headache clinics. Psychiatric comorbities, such as dependency-like behaviors, anxiety and mood symptoms, might account for headache-related disability and recurrent relapses into medication overuse after a successful detoxification. Within a sample of 63 chronic migraineurs with medication overuse and severe disability, we investigated to which extent clinical severity, affective states and attitudes about medication impact the overall functioning at time of detoxification. To unravel whether some of these factors could predict their long-term outcome, we followed and retest them 1 year after withdrawal. We hypothesized that the detoxification would have led to a partial improvement and not modified the attitudes toward medication and dependence. Detoxification improves most of the clinical and affective measures, but does not free from significant levels of pain intensity and headache-related disability. The partial benefit from detoxification, the severity bias and the maladaptive cognitive profile led us to believe that subgroups of chronic-relapsing migraineurs deserve a multidisciplinary approach that addresses not only the reduction of clinical severity but also specific cognitive and behavioral impairments.

Psychological and neuropsychological correlates of dependence-related behaviour in medication overuse headaches: a one year follow-up study

Background

Medication Overuse Headache (MOH) can be related in some patients to dependence-related behaviour characterised by craving, a deficit in controlling substance intake, which is associated to orbitofrontal cortex (OFC) dysfunction. The aim of this study was to explore the psychological correlates in MOH patients and the functioning of the OFC through neuropsychological assessment (Iowa Gambling Task: IGT) and to relate it to prognosis at a one year follow-up point.

Findings

Seventeen subjects suffering from probable MOH were included and compared to 19 migraineurs and to 17 controls. The results show significant between group differences for behavioural dependence, depression, anxiety, catastrophizing. There were no between group differences for impulsivity. Mean IGT score did not allow differentiation of MOH patients from the other groups, whereas the score was significantly different between opiate abusers and other medication abusers (45 +/−5.7 versus 57.1 +/−8.2, p = 0.019). Among the clinical variables rated at inclusion, the amount of acute headache medication taken per month was the only one predicting the prognosis (RR = 1.05, 95% CI = 1-1.06, p = 0.04). A slight increase in risk of relapse at 1 year was observed in patients with poorer IGT scores (RR = 0.92, 95% CI = 0.85-1, p = 0.05) and higher behavioural-dependence scores (RR = 1.07, 95% CI = 1–1.14, p = 0.05). None of the other psychological variables predicted relapse risk.

Conclusions

These results must be interpreted with caution due to the low number of subjects. They showed a deficit in decision making processes in MOH patients who overuse medications containing psychoactive substances like opiates. Moreover dependence-related variables are related to the prognosis.