Neuroimaging Findings in Patients with Medication Overuse Headache

Headache Attributed to a Substance or Its Withdrawal

Identification of substances that may cause or trigger headache is important to start effective treatment early to prevent unnecessary suffering, deterioration in quality of life, and the development of chronic pain. Treatment in case of medication overuse and other chronic headache should be decisive and effective. Drug withdrawal and introduction of effective prophylactic medication for the underlying headache disorder should be the primary treatment strategy. Typical headache-inducing substances are nitric oxide, phosphodiesterase, cocaine, alcohol, histamine, carbon oxide, and calcitonin gene-related peptide. The withdrawal of caffeine, estrogen, and opioids is most often associated with the development of headache.

Beyond Pain: The Effects of OnabotulinumtoxinA Therapy on Sensitization and Interictal Symptoms in Chronic Migraine

Chronic migraine is a disease with a high burden on patients from both a working and quality of life point of view. The pathophysiology of this subtype of migraine is due to several factors, such as medication overuse. Nevertheless, the detrimental recurring of headache attacks with central and peripheral sensitization plays a central role and explains some additional symptoms complained about by these patients even in the interictal phase. OnabotulinumtoxinA is a therapy indicated for chronic migraine since it has proven to reduce peripheral sensitization, showing even efficacy on central symptoms. The aim of this narrative review is to present the current evidence regarding the effect of OnabotulinumtoxinA on sensitization and interictal symptoms.

Medication Overuse Headaches among Children-The Contribution of Migraine and TTH

Medication overuse headaches are a frequent phenomenon observed in individuals suffering from chronic headaches. It arises due to the excessive consumption of pain-relief medications, resulting in the escalation and continuous persistence of headache symptoms. Nevertheless, the prevalence and distinctive characteristics of medication overuse headaches in the pediatric population have not been comprehensively explored. The primary objective of this research is to delineate the features of medication overuse headaches in children, particularly emphasizing the investigation of its epidemiology and the diagnostic patterns for headaches. We conducted a retrospective study and analyzed the medical records of children and adolescents who were evaluated at the outpatient pediatric headache clinic at the Bnai Zion Medical Center for headaches during the period spanning 2007 to 2017. Our study encompassed a cohort of 1008 patients experiencing headaches. Among these participants, 268 individuals (26.6%) were diagnosed with migraine, 250 (24.8%) exhibited tension-type headaches (TTH), and 490 (48.6%) were classified as having undifferentiated headaches. Out of the whole group, 65 had chronic headaches: 35 (54%) with migraine, 20 (30%) with tension-type headaches (TTH), and 10 (15%) with the undifferentiated headache of childhood, with the majority (73%) being female. In summary, medication overuse headaches are a prevalent issue among children grappling with chronic headaches. Intriguingly, they appear to be more pronounced within the tension-type headache (TTH) group compared to migraine sufferers and exhibit a higher prevalence among females. This study underscores the significance of early detection and careful management of medication overuse headaches in pediatric cases, shedding light on its distinct characteristics in the realm of childhood headache disorders. Further research is warranted to elucidate the underlying factors contributing to the observed gender disparity and the distinct prevalence rates among different headache subtypes.

Medication overuse headache: a review of current evidence and management strategies

The third edition of the International Classification of Headache Disorders (ICHD-3) defines medication-overuse headache (MOH) as a headache that develops when a person regularly uses acute or symptomatic headache medications excessively (10 or more, or 15 or more days per month, depending on the medication) for a period of time longer than 3 months. Even though it may not be reported as frequently as it actually is, it affects about 5% of the general population on average. It typically happens following repeated anti-pain medication use for pre-existing headache disorders, such as migraines. Anti-pains can also be used frequently in patients with pre-existing headache disorders for reasons other than treating headaches, such as psychological drug attachment. MOH is linked to a number of illnesses, such as anxiety, depression, and obsessive compulsive disorder (OCD). Both simple and complex types are possible. Additionally, there is no universal consensus on how to treat MOH, but drug discontinuation is the best course of action. Using the medical subject headings "Medication Overuse Headache," "Migraine Headache," "Tension Headache," "Chronification of Headache," and "Antipains," an all-language literature search was done on PubMed, Google Scholar, and Medline up until March 2023. We looked into the epidemiology, risk factors, pathophysiology, clinical characteristics, comorbidities, diagnosis, management, and preventative measures of MOH in the literature. This article focuses on the MOH research themes.

Expression of Selected microRNAs in Migraine: A New Class of Possible Biomarkers of Disease?

Preliminary but convergent findings suggest a role for microRNAs (miRNAs) in the generation and maintenance of chronic pain and migraine. Initial observations showed that serum levels of miR-382-5p and miR-34a-5p expression were increased in serum during the migraine attack, with miR-382-5p increasing in the interictal phase as well. By contrast, miR-30a-5p levels were lower in migraine patients compared to healthy controls. Of note, antimigraine treatments proved to be capable of influencing the expression of these miRNAs. Altogether, these observations suggest that miRNAs may represent migraine biomarkers, but several points are yet to be elucidated. A major concern is that these miRNAs are altered in a broad spectrum of painful and non-painful conditions, and thus it is not possible to consider them as truly “migraine-specific” biomarkers. We feel that these miRNAs may represent useful tools to uncover and define different phenotypes across the migraine spectrum with different treatment susceptibilities and clinical features, although further studies are needed to confirm our hypothesis. In this narrative review we provide an update and a critical analysis of available data on miRNAs and migraines in order to propose possible interpretations. Our main objective is to stimulate research in an area that holds promise when it comes to providing reliable biomarkers for theoretical and practical scientific advances.

Enhanced functional connectivity between habenula and salience network in medication-overuse headache complicating chronic migraine positions it within the addiction disorders: an ICA-based resting-state fMRI study

Background

Medication-overuse headache (MOH) is a relatively frequently occurring secondary headache caused by overuse of analgesics and/or acute migraine medications. It is believed that MOH is associated with dependence behaviors and substance addiction, in which the salience network (SN) and the habenula may play an important role. This study aims to investigate the resting-state (RS) functional connectivity between the habenula and the SN in patients with MOH complicating chronic migraine (CM) compared with those with episodic migraine (EM) and healthy controls (HC).

Methods

RS-fMRI and 3-dimensional T1-weighted images of 17 patients with MOH + CM, 18 patients with EM and 30 matched healthy HC were obtained. The RS-fMRI data were analyzed using the independent component analysis (ICA) method to investigate the group differences of functional connectivity between the habenula and the SN in three groups. Correlation analysis was performed thereafter with all clinical variables by Pearson correlation.

Results

Increased functional connectivity between bilateral habenula and SN was detected in patients with MOH + CM compared with patients with EM and HC respectively. Correlation analysis showed significant correlation between medication overuse duration and habenula-SN connectivity in MOH + CM patients.

Conclusions

The current study supported MOH to be lying within a spectrum of dependence and addiction disorder. The enhanced functional connectivity of the habenula with SN may correlate to the development or chronification of MOH. Furthermore, the habenula may be an indicator or treatment target for MOH for its integrative role involved in multiple aspects of MOH.

[Cognitive and emotional disorders in patients with migraine and signs of leukoencephalopathy]

OBJECTIVE

To identify cognitive and emotional disorders and their correlation with neuroimaging parameters in patients with chronic migraine.

MATERIAL AND METHODS

We examined 50 patients (8 men and 42 women, mean age 41.9±11.9 years) with migraine, including 31 with chronic migraine, and signs of leukoencephalopathy according to magnetic resonance imaging (MRI). A control group comprised 40 healthy individuals (13 men and 27 women) aged 20 to 64 years (mean 42.6±12.0 years). A number of tests for neuropsychological examination and assessment of the emotional state, including a 12-word test, literal and categorical associations, Benton Test, the Montreal cognitive scale (MOCA), the Hospital Depression Scale, the Beck Depression Scale, the Center for Epidemiological Research scale, the Hospital Anxiety Scale and the Spielberger-Khanin scale, were administered at baseline and after 3 and 6 month of preventive therapy.

RESULTS

Patients with migraine had lower scores (p=0.004) on MOCA, memorization of 12 words (p=0.0003), test for literal (p=0.001) and categorical associations (p=0.0002) compared with the control group. No significant correlations were found between the volume of white matter lesions according to MRI and the severity of cognitive impairment. An inverse correlation of average strength was noted (correlation coefficient R=-0.41) between the number of days with headache per month and the MOCA score (p<0.05). In patients with migraine, signs of depression were found on the Hospital Depression Scale (p=0.04), Beck Depression Scale (p=0.003), the Center for Epidemiological Research scale (p=0.0001), and increased anxiety on the Hospital Anxiety Scale (p=0.0001) and the Spielberger-Khanin scale (p=0.0001). A significant relationship was found between the degree of depression and the MOCA score (p=0.007). The frequency of headaches decreased from 19.4±2.9 to 12.6±4.4 days per month (p<0.05).

CONCLUSION

There were a significant decrease of emotional disorders and improvement of cognitive functions compared with baseline scores during the 6 month therapy. Preventive treatment of migraine and concomitant emotional disorders seems to be the most effective way to improve cognitive functions.

Gepants, calcitonin-gene-related peptide receptor antagonists: what could be their role in migraine treatment?

PURPOSE OF REVIEW

Migraine is the second leading cause of years lived with disability after back pain. Poor tolerability, contraindications, drug-drug interactions and efficacy limited to a subpopulation make new approaches necessary for the acute and preventive treatment of migraine. The study of the calcitonin-gene-related peptide (CGRP) pathway over the last decades is a good example of translational medicine leading to directed therapies for patients.

RECENT FINDINGS

After some of the first-generation CGRP receptor antagonists, gepants, were not fully developed because of hepatotoxicity, the second generation of gepants have shown efficacy, safety and tolerability in recent clinical trials.

SUMMARY

Both rimegepant and ubrogepant have published positive randomized placebo-controlled clinical trials data. Vazegepant is the first intranasal gepant for the acute treatment of migraine and has announced a positive phase II/III study. Daily rimegepant use has preliminary data to suggest efficacy. Atogepant has shown efficacy in migraine prevention in a phase II/III study. Most importantly, hepatotoxicity has not been reported in specifically designed phase I studies or long-term extension studies, with rimegepant or ubrogepant, or in a preventive study with atogepant. Given the preventive effect, it seems likely that gepants will not lead to medication overuse headache. They will likely have no cardiovascular warnings. Because of the particular benefit gepants may represent for these groups of patients, specific studies in patients with medication overuse headache, as well as those with comorbid cardiovascular diseases, would be of considerable interest.

The implication of morphometrics and growth rate of dipteran flies in forensic entomotoxicology research: a review

Forensic entomotoxicology integrates toxicology into forensic entomology to estimate minimum postmortem interval (PMI_min) and circumstances of death where toxicants and poisonous substances are the suspected cause of death. Forensic entomotoxicology not only confirms the presence of toxicants in insects feeding off a cadaver but also studies its effect on the bio-morphometry and growth rate of insects. This review article highlights the effects of various toxicants on forensically important species of dipteran flies. It also discusses the parameters that may affect accuracy in estimation of time since death. The bio-physical effects of toxicants (excluding the analytical approach for qualitative detection) would help understand the trends in forensic entomotoxicological research worldwide.

Secondary headache attributed to exposure to or overuse of a substance

BACKGROUND

Secondary headaches attributed to exposure to or the overuse of a substance are classified under chapter eight in the International Classification of Headache Disorders 3rd edition. Three distinct sub-chapters consider: 1. Headache attributed to exposure to a substance, 2. Medication overuse headache, and 3. Headache attributed to substance withdrawal. Headache attributed to exposure to a substance refers to a headache with onset immediately or within hours after the exposure, while medication overuse headache is a headache occurring on 15 or more days per month that has developed as a consequence of regular usage of acute headache medication(s) for more than three consecutive months in a patient with a pre-existing primary headache disorder. The withdrawal of caffeine, oestrogen, and opioids is most often associated with the development of headache.

DISCUSSION

Despite the current headache classification, there is no certainty of a causal relationship between the use of any substance and the development of headache. Some substances are likely to provoke headache in patients that suffer from a primary headache disorder like migraine, tension-type headache or cluster headache, while others were described to cause headache even in people that generally do not get headaches. Toxic agents, such as carbon monoxide (CO) are difficult to investigate systematically, while other substances such as nitric oxide (NO) were specifically used to induce headache experimentally. If a patient with an underlying primary headache disorder develops a headache, in temporal relation to exposure to a substance, which is significantly worse than the usual headache it is considered secondary. This is even more the case if the headache phenotype is different from the usually experienced headache characteristics. Medication overuse headache is a well-described, distinct disease entity with only marginally understood pathophysiology and associated psychological factors. Managing medication overuse headache patients includes education, detoxification, prophylactic treatments and treating comorbidities, which is reflected in available guidelines. Viewing medication overuse headache as a separate entity helps clinicians and researchers better recognise, treat and study the disorder.

CONCLUSION

Identification of substances that may cause or trigger secondary headache is important in order to educate patients and health care professionals about potential effects of these substances and prevent unnecessary suffering, as well as deterioration in quality of life. Treatment in case of medication overuse and other chronic headache should be decisive and effective.

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.

The Many Faces of Medication-Overuse Headache in Clinical Practice

The management of medication-overuse headache (MOH) is multifaceted and headache experts have different views on the optimal strategy to tackle this type of secondary headache. The purpose of this review is to provide an overview of the literature on the management of MOH, and to highlight important considerations in the clinical evaluation of the MOH patient. Managing MOH in clinical practice starts by evaluating the headache patient with medication overuse, determining the overused drug(s), assessing the impact of headaches on the patient and assessing comorbid conditions and disorders. Withdrawal of the overused medication is the cornerstone of treatment. An inpatient or outpatient setting is chosen based on the clinical profile of the patient. There is evidence for abrupt withdrawal combined with headache preventive treatment. Bridging therapy to bring relief to withdrawal headaches and/or symptoms should be offered. Education and motivational work through multidisciplinary assessment show benefits in sustaining withdrawal and preventing relapse. Although the reversal of chronic headache after cessation of overused acute medication has been noticed worldwide, different aspects of the management of MOH, such as complete or gradual withdrawal, or preventive treatment with or without withdrawal are still debated.

Brain metabolites in chronic migraine patients with medication overuse headache

BACKGROUND

Medication overuse headache may be associated with widespread alterations along the thalamocortical pathway, a pathway involved in pain perception and disease progression. This study addressed whether brain metabolites in key regions of the thalamocortical pathway differed between chronic migraine patients with medication overuse headache and without medication overuse headache.

METHODS

Magnetic resonance spectroscopic imaging was used to map metabolites in the bilateral anterior cingulate cortices, mid cingulate cortices, posterior cingulate cortices, and the thalami. Sixteen patients with medication overuse headache were compared with 16 matched patients without medication overuse headache and 16 matched healthy controls.

RESULTS

Glutamate and glutamine in the right mid cingulate cortex and myo-inositol in the left anterior cingulate cortex were significantly higher in patients with medication overuse headache than patients without medication overuse headache, but similar to healthy controls. Both patient groups exhibited reduced N-acetyl-aspartate and creatine in the thalamus, reduced myo-inositol in the right anterior cingulate cortex, and elevated choline in the right mid cingulate cortex. Finally, a negative association between myo-inositol laterality index in the anterior cingulate cortices and number of days per month with acute medication use was found across all patients.

CONCLUSIONS

Patients with medication overuse headache were characterized by a distinct concentration profile of myo-inositol, a glial marker, in the anterior cingulate cortices that may have arisen from medication overuse and could contribute to the development of medication overuse headache.

Multisensorial Perception in Chronic Migraine and the Role of Medication Overuse

Multisensory processing can be assessed by measuring susceptibility to crossmodal illusions such as the Sound-Induced Flash Illusion (SIFI). When a single flash is accompanied by 2 or more beeps, it is perceived as multiple flashes (fission illusion); conversely, a fusion illusion is experienced when more flashes are matched with a single beep, leading to the perception of a single flash. Such illusory perceptions are associated to crossmodal changes in visual cortical excitability. Indeed, increasing occipital cortical excitability, by means of transcranial electrical currents, disrupts the SIFI (ie, fission illusion). Similarly, a reduced fission illusion was shown in patients with episodic migraine, especially during the attack, in agreement with the pathophysiological model of cortical hyperexcitability of this disease. If episodic migraine patients present with reduced SIFI especially during the attack, we hypothesize that chronic migraine (CM) patients should consistently report less illusory effects than healthy controls; drugs intake could also affect SIFI. On such a basis, we studied the proneness to SIFI in CM patients (n = 63), including 52 patients with Medication Overuse Headache (MOH), compared to 24 healthy controls. All migraine patients showed reduced fission phenomena than controls (P < .0001). Triptan MOH patients (n = 23) presented significantly less fission effects than other CM groups (P = .008). This exploratory study suggests that CM - both with and without medication overuse - is associated to a higher visual cortical responsiveness which causes deficit of multisensorial processing, as assessed by the SIFI. PERSPECTIVE: This observational study shows reduced susceptibility to the SIFI in CM, confirming and extending previous results in episodic migraine. MOH contributes to this phenomenon, especially in case of triptans.

Eighty years of Medication-Overuse Headache: what about Medication-Overuse Backpain?

INTRODUCTION

Although chronic low back pain (CLBP) is one of the most common pain syndromes, up to now, clear pathophysiological causes or specific treatment options are missing. Medication-overuse has been associated with chronic headache, but never with CLBP.

HYPOTHESIS

Based on several similarities between CLBP and Medication-Overuse Headache (MOH), we hypothesized that medication-overuse might contribute to CLBP as well, maybe even as an own entity. Might there be something like Medication-Overuse Backpain (MOB)?

METHODS

We substantiate our hypothesis with a preliminary case-series analyzing five patients suffering from CLBP with a marked medication-overuse. In these patients, a stepwise analgesic withdrawal was recommended.

RESULTS

Within 6 months of recruitment, five patients fulfilled the inclusion criteria and successfully completed discontinuation of their medication. All patients reported noticeable pain relief, despite the discontinuation of their analgesics. Withdrawal was well tolerated in all cases.

CONCLUSIONS

Considering our results, the described withdrawal method seems to be a simple and safe method to achieve pain reduction while simultaneously preventing organ damage. Despite the preliminary character of our results, our hypothesis might stimulate a new understanding of CLBP's pathophysiology.

Emerging Novel Pharmacological Non-opioid Therapies in Headache Management: a Comprehensive Review

PURPOSE OF REVIEW

Chronic headache is a significant worldwide problem despite advances in treatment options. Chronic headaches can have significant a detrimental impact on the activities of daily living.

RECENT FINDINGS

Patients who do not obtain relief from chronic head and neck pain from conservative treatments are commonly being managed with interventional treatments. These interventional treatment options include botulinum toxin A, injections, local occipital nerve anesthetic and corticosteroid infiltration, occipital nerve subcutaneous stimulation and occipital nerve pulsed radiofrequency (PRF), sphenopalatine ganglion block, and radiofrequency techniques. Recently, evidence has emerged to support non-opioid-based drug and interventional approaches. Overall, more research is necessary to clarify the safety and efficacy of interventional treatments and to better understand the pathogenesis of chronic headache pain.

Personality and Personality Disorders in Medication-Overuse Headache: A Controlled Study by SWAP-200

Background

Medication-overuse headache (MOH) is a type of chronic headache, whose mechanisms are still unknown. The impact of psychological factors has been matter of debate from different perspectives. The role of personality and personality pathology in processes involved in MOH development has been advanced but was poorly studied. The hypothesis of addiction-like behaviors sustaining the drug misuse has been examined and reached contrasting findings.

Objectives

This study is aimed at detecting personality and its disorders (PDs) in MOH, with a specific attention to the addiction aspect.

Methods

Eighty-eight MOH patients have been compared with two clinical populations including 99 patients with substance use disorder (SUD) and 91 with PDs using the Shedler-Westen Assessment Procedure-200 (SWAP-200), a clinician-report tool that assesses both normal and pathological personality. MANCOVAs were performed to evaluate personality differences among MOH, SUD, and PD groups, controlling for age and gender.

Results

MOH patients were predominantly women and older. They showed lower traits of the SWAP-200's cluster A and B disorders than SUD and PD patients, who presented more severe levels of personality impairment. No differences in the SWAP-200's cluster C have been found, indicating common personality features in these populations. At levels of specific PDs, MOH patients showed higher obsessive and dysphoric traits and better overall psychological functioning than SUD and PD patients.

Conclusion

Although MOH, SUD, and PD populations have been evaluated in multiple sites with different levels of expertise, the study supported the presence of a specific constellation of personality in MOH patients including obsessive (perfectionist) and dysphoric characteristics, as well as good enough psychological resources. No similarities to drug-addicted and personality-disordered patients were found. Practitioners' careful understanding of the personality characteristics of MOH patients may be useful to provide a road map for the implementation of more effective treatment strategies and intervention programs.

Pathophysiology, prevention, and treatment of medication overuse headache

Regular or frequent use of analgesics and acute antimigraine drugs can increase the frequency of headache, and induce the transition from episodic to chronic headache or medication overuse headache. The 1-year prevalence of this condition in the general population is between 1% and 2%. Medication overuse headache is more common in women and in people with comorbid depression, anxiety, and other chronic pain conditions. Treatment of medication overuse headache has three components. First, patients need education and counselling to reduce the intake of medication for acute headache attacks. Second, some patients benefit from drug withdrawal (discontinuation of the overused medication). Finally, preventive drug therapy and non-medical prevention might be necessary in patients at onset of treatment or in patients who do not respond to the first two steps. The optimal therapeutic approach requires validation in controlled trials.

Depression is not the only cause of cognitive impairment in chronic migraine

Background. Patients with the chronic migraine frequently present with memory and attention complaints. However, the prevalence and phenotype of such impairment in chronic migraine have not been studied.

Objective – to evaluate the prevalence of the objective cognitive deficit in patients with chronic migraine and factors underlying its etiology.

 Materials and methods. We recruited 62 subjects with chronic migraine and 36 genderand age-matched controls with low-frequency episodic migraine (not more, then 4 headache days per month) aged 18–59. All patients filled in the Hospital Anxiety and Depression Scale (HADS) and Sheehan Disability Scale. Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA), Digital Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), and the Perceived Deficits Questionnaire (PDQ-20).

Results. In this study 58 % of patients with chronic migraine complained of memory loss. Cognitive impairment was also found with PDQ-20. Objectively, we found a significant decrease in 90-second DSST results and RAVLT total recall and learning rate. In 40 % of subjects with chronic migraine scored lower than 26 points on MoCA. Patients with chronic migraine more frequently had lower DSST rates as compared to episodic migraine (odds ratio 5.07 (95 % confidence interval – 1.59–16.17); p = 0.003). Depression and anxiety did not correlate with performance on cognitive tests. Chronic migraine (frequent headache) and longer headache history, but not depression, anxiety or medication overuse were independent predictors of cognitive impairment.

Conclusion. Subjective and objective cognitive deficits are prevalent in the chronic migraine population. Most often memory and attention are impaired. Longer headache history and presence of chronic migraine are independent risk factors for cognitive impairment in patients with chronic migraine.

Chronic pain, depression and cognitive impairment: a close relationship

Over a half of chronic pain (CP) patients present with cognitive complaints, which increase their disability and impact quality of life. The paper reviews objective impairments in memory, attention, processing speed and executive function demonstrated in the CP population. The paper also reviews common pathology underlying cognitive impairment and CP: neuroplasticity in the shared brain areas, neurotransmitter and other molecular mechanisms. Common mechanisms in CP and depression precipitating cognitive impairment are also discussed. The paper also compares the potential of different antidepressants to improve cognitive functions in depression and CP.

Medication-overuse headache: a widely recognized entity amidst ongoing debate

Medication overuse in primary headache disorders is a worldwide phenomenon and has a role in the chronification of headache disorders. The burden of disease on individuals and societies is significant due to high costs and comorbidities. In the Third Edition of the International Classification of Headache Disorders, medication-overuse headache is recognized as a separate secondary entity next to mostly primary headache disorders, although many clinicians see the disease as a sole complication of primary headache disorders. In this review, we explore the historical background of medication-overuse headache, its epidemiology, phenomenology, pathophysiology and treatment options. The review explores relevant unanswered questions and summarizes the current debates in medication-overuse headache.