Headache is mostly self-managed [14,15] and headache prescription medications account only partly for the total medication use for headache since most patients buy over-the-counter (OTC) drugs [5,6,16-19]. Headache accounts for 4% of the general practitioners (GPs) consultations [19], and is probably the most common reason for referral to neurologists [19,20]. Approximately 20–30% of all new referrals to out-patients neurological departments are due to headache [21,22].

Analgesic use, misuse and overuse represent major health problems associated with numerous adverse health consequences. A population-based study from Norway which included about 50,000 subjects found that 10% reported taking analgesics currently on a daily basis and up to 5% reported taking analgesics on a daily basis for at least six months [23]. Results from another Norwegian study showed that 28% of men and 13% of women had used analgesics over the preceding 28-day period, mostly to treat headaches [24]. Frequent intake of analgesics may, however, worsen headache and lead to chronification and Medication Overuse Headache (MOH) [25-27]. MOH is a condition with chronic headache in combination with overuse of acute headache medication(s) [25-27]. The prevalence of MOH in the general population is 1–2% [5,6,10,25-28]. The condition was first described for egotamines in 1951 [29] and it is now substantiated that all drugs used for the acute treatment of headache can cause MOH in patients with a pre-existant headache disorder [25-27]. The proportion of MOH is lower in the general population than one sees in clinical settings, and the distribution of the overused medication differs with simple analgesics being most frequently overused in the general population [7,9,17,28,30-35].

The aims of MOH management are [36,37]

i. withdrawal of the overused drug(s)

ii. to provide the patient with pharmacological and non-pharmacological support

iii. to prevent relapse

Detoxification from the overused medication often leads to headache improvement [25,26,31,38], but is often complicated by temporary withdrawal symptoms such as worsening of headache, nausea, vomiting, hypotension, tachycardia, sleep disturbances, restlessness, anxiety and nervousness which typically occur 2–10 days after detoxification [26,27,40,41]. There is no established optimal withdrawal method for MOH though many different strategies have been suggested [25,36,37,39]. These include use of antiemetics and/or neuroleptics to reduce abstinence-like symptoms, intravenous administration of ergotamines and substitution of the offending painkiller with another. Steroid treatment has also been used to alleviate withdrawal reactions though this strategy is controversal [36,37,41-43].

Regarding prophylactic headache medication, there is also an ongoing discussion whether this should be initiated immediately at withdrawal or after completed withdrawal therapy [36,44].

Follow-up studies of various duration have reported relapse rates between 20–60% and findings from these studies suggest that patients have the highest risk of relapse within the first year after withdrawal [37,45-49].

MOH is a heterogenous disorder which has been suggested to include both subgroups with simple medication overuse as well as more complex detoxification-resistant cases [36,50-52]. Some of these cases may be more “dependency-like” and it has indeed been suggested that MOH shares some common neurobiological pathways with drug dependence and that MOH therefore may represents a kind of addictive behaviour [53]. Whether this applies to all MOH cases or specific subgroups defined by this particular “dependency-like” behaviour (eg. “complex” MOH) remains to be demonstrated. Two studies have demonstrated that most MOH patients fulfill criteria for dependency according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) [54-56]. Another study found that the dependency score based on the Leeds Dependency Questionnaire was similarly increased in MOH patients and illegal drug addicts [57].

Over the past decades several dependency assessment scales have been developed. The Severity of Dependence Scale (SDS) is a simple, validated scale which scores psychological dependence on a number of different substances [58-63]. Previous studies from our group have revealed that the SDS has both high sensitivity, specificity, positive and negative predictive values for detecting persons with MOH among chronic headache patients. [30,35,64]. In addition, the SDS score has been shown to predict likelihood of successful detoxification in a general population [65].

Screening and Brief Intervention (BI) is a well-known approach to identify and treat unhealthy alcohol use [66]. The SDS and similar scales such as the Alcohol Use Disorders Identification test, have previously been used to identify individuals at risk for addiction-related problems [58-63,67-69]. BI involves the use of such an identification tool followed by feedback to the identified individual as being “at risk”. The final step, in this very short and simple intervention is to give information suggesting to cut down the use of the particular substance to predecided “acceptable” levels [66]. BI includes clear directive advice, but focus is also on increasing patients insight and awareness regarding overuse as described in more detail elsewhere [66,70]. The BI method has shown promising results with both short- and longlasting reduction of alcohol intake and levels of related biochemical markers such as liver transferase levels [66,71-73]. Similar methods have also been successfully applied for various other addictive drugs [70,74,75].

We have previously reported data from an open, un-controlled study of medication overuse headache in the general population, which suggested that three out of four MOH subjects had managed to reduce their medication intake after short information [76]. Similar simple advice also works in clinic settings [77,78]. One population- and one clinic-based study suggest that MOH can be successfully managed in a primary care setting after an initial collaboration with headache specialists [45,79].

The common headache disorders require no high-tech investigations and may therefore be diagnosed and managed by all skilled physicians. Most headaches are therefore probably best managed in primary care. Focus on MOH in primary care is therefore important both in order to prevent MOH from developing and for early diagnosis and treatment.

We have designed a BI for treatment of MOH in primary care and planned a double-blinded cluster randomized parallel controlled trial (RCT) to evaluate effects of the intervention.

To our knowledge, this is the first double-blinded cluster-randomized controlled clinical trial for MOH in primary care.

The GPs that will be included in the present study are assumed to be representative for Norwegian GPs in general in terms of localisation (urban vs. suburban), gender and age distribution. Through the Norwegian GP list-patient system, all citizens are listed with a GP. Therefore, with a representative selection of GPs, the patient population is assumed to be reasonably population-based which will increase the external validity of our findings.

The age range of patients (18–50 years of age) has been chosen in order to target the highest number of patients with chronic headache, as the prevalence is lower in younger people and older people have a higher frequency of co-morbidities. We have chosen an upper age limit of 50 years since data from the Norwegian prescription database (NorPD) also indicate that there is an increase in the number and dosage of various relevant drugs (notably anti-hypertensives and cardiovascular drugs) at approximately 50 years of age [104] and we want to monitor headache medication and not the use of drugs prescribed for other illnesses.

Selection bias may occur by just including patients who are willing to cooperate in the intervention; however the same selection will take place in the control group. The selection of participating GPs are based on voluntary participation and the BIC will give them CME credits. Our GPs might therefore have a higher motivation for the BI than GPs in general, but this selection will also take place in the control group. Gains for participating GPs are: i) improvement in headache diagnostics and management ii) receiving a tool for identifying and detoxifying MOH patients.

The study group will cover the normal fee for the BI consultation for the patients, apart from this there are no economic incentives for participation either for the patients or the GPs.

Although questionnaires cannot replace an encounter with a skilled physician, single questions about migraine and tension-type headache and frequency of tension-type headache have been shown to be valid [80,81]. However, especially among those with chronic or co-occurring headache types, diagnosing headaches is not always easy. The gold standard for making a specific headache diagnosis is an interview combined with a physical and neurological examination by a physician experienced in headache diagnostics. All patients will be diagnosed based on interviews by a GP trained and experienced in headache diagnostics also in order to avoid inter-observer variation (ESK).

Some of our data will be based on retrospective self-reports and therefore open to recall bias, although here is no reason to suspect systematic bias. In order to counteract this, we will also use headache data from prospective headache diaries [87]. Recent studies using a similar headache diary with written instructions before first consultation found high usefulness, acceptability and comprehensibility of the diary as well as good compliance and completeness of data [105,106]. We will use the headache diary for periods of two weeks. This period may seem too short for infrequent forms of headache, but in our sample of chronic sufferers this should not be a problem. In addition, a longer headache registration period may reduce compliance and cause greater interference with the cohort.

A common finding in many brief intervention studies and RCTs on alcohol use, are small reductions in alcohol consumption at follow-up also in the control group [73,107]. Possible reasons for this may be motivational effects of screening, sensitization to screening/measurements/follow-up, non-intended advice also in BAU group, and “regression towards the mean”. In this study we have tried to minimize most assessment effects by doing a double-blinded parallel RCT, and the screening questionnaire about medication use for headache is embedded with other questions about headache in the very short screening questionnaire. The control group will not receive the SDS screening before the three months follow-up and will therefore not be affected by this.

The SDS has not been validated against other measurements of dependency in MOH sufferers and, indeed, there is still much discussion as to whether MOH represents dependency [50-55,57]. Being fully aware of this, we will use the SDS score, not as an attempt to define dependency, but rather to distinguish between chronic headache subjects with and without medication overuse [30,35].

A Danish study has shown that feasibility, acceptability and implementation of screening and brief intervention programs for alcohol overuse in primary care may cause more problems than they solve for some GPs because it might be problematic to incorporate a brief intervention and follow-up in a busy daily practice where many other different problems are targeted [108]. It is clear that if physicians, and especially GPs, are to deliver interventions in a busy daily and routine practice, it is of great importance that the interventions are feasible and considered clinically relevant. We have used knowledge and experience from a study on the epidemiology of headache in Norway [5,6], a prescription peer academic detailing study [109,110], and a pilot study to investigate some of these aspects, and used this to design the final structure and contents of both the BIC and the study to be both acceptable for patients and feasible for GPs in daily practice.

To reduce the workload for participating GPs as well as for blinding purposes, the first universal/opportunistic screening for chronic headache and probable medication overuse will be performed by the external project administration prior to the BI. Through this screening we also expect to reach possible chronic headache patients who might not be known as such by their GP. Apart from this initial screening, the study is a pragmatic trial tailored to fit into a busy situation of an everyday GP.

We suggest that strengths of this study include the design and approach with randomly assigned intervention and control groups in accordance with the CONSORT statement for RCTs [111].