Normal and pathological anxiety
Anxiety is a common mental health problem seen in primary care. Anxiety can be defined as an anticipation of future harm or misfortune, accompanied by a feeling of unpleasantness and/or somatic symptoms of tension. This feeling is normal in the face of certain day-to-day stressing situations. When it exceeds a certain intensity or overwhelms a person's adaptive capacity, anxiety becomes pathological. Anxiety disorders are a group of illnesses characterized by the presence of worry, excess of fear or dread, tension, or activation that causes a notable uneasiness or a clinically significant deterioration of an individual's activity .
The causes of anxiety disorders are not entirely known, but biological factors, as well as environmental and psychosocial ones, are involved [2–4]. Some authors say that it is the interaction of multiple determining factors that favours the appearance of these anxiety disorders . In addition, co-morbidity with other mental disorders, such as mood disorders, is very common [3–6].
The proper diagnosis, treatment, and, in those cases where necessary, appropriate referral of anxiety disorders to mental health services, is fundamental for effective clinical management [7, 8].
Anxiety as a health problem
The prevalence of anxiety disorders varies depending on different epidemiological studies, with prevalence-year and prevalence-life being set at between 10.6% and 16.6% . Data for Spain from the European Study of the Epidemiology of Mental Disorders (ESEMeD) estimate a prevalence-year of 5.1% [10, 11]. Mental disorders represent a burden for individuals, as well as for families and the community. In the case of the community of Madrid, neuropsychiatric illnesses are confirmed as the first cause of adjusted years of life for incapacity .
According to the World Health Organization's report on mental health, 20% of all patients attended by primary care professionals suffer one or more mental disorders. This report recommends that management and treatment be performed as far as possible in primary care so as to facilitate access to services for the greatest number of people possible .
Clinical practice guidelines (CPGs) as a tool for the management of anxiety disorders in primary care
The diagnostic and therapeutic approach to these disorders varies widely. Primary care professionals have different grades of training in the area of mental health, in psychiatric interview skills, as well as in psychological intervention techniques [14–16].
A study in the United States between 1985 and 1998 described an increase in the use of psychopharmaceutical medication in primary care visits (38.7% compared with 54.6%) while, at the same time, it showed a constant drop in the use of psychological interventions (6.8% to 2%) in the treatment of anxiety disorders .
CPGs are a good tool to reduce this variability and improve evidence informed in the clinical decision-making. In Spain, the Ministry of Health and Social Policy has put into effect the 'Guiasalud' project  to draft CPGs. In the framework of this project, the Clinical Practice Guideline for the Approach to Anxiety Disorders in Primary Care has been drafted in coordination with the Technologies Assessment Unit of the Agencia Lain Entralgo .
The scope of the CPG covers the diagnosis and management of adult patients with generalized anxiety disorders (GAD) and panic disorder (PD), with or without agoraphobia, in the context of primary care.
Two aspects of this CPG development are worth noting. The first is the involvement of patients with anxiety disorders in all phases of the development process. The second is that the CPG includes interventions that can be carried out by the various professionals working in primary care. These interventions are carried out at the primary healthcare centers, mainly by nursing and/or social workers . Likewise, it is worth noting the low utilization of psychological interventions of proven effectiveness . Our group has carried out a study that focuses on the evaluation of the effectiveness of the intervention groups directed by nurses in patients with anxiety in primary care .
The Goldberg Anxiety and Depression Scale (GADS) has been included in the guideline to evaluate the changes obtained by the various interventions and as a way to provide key questions to guide the clinical interview. This scale has been chosen because it is brief and easy to manage and interpret [22–24]. The Spanish version has demonstrated its reliability and validity within the ambit of primary care, and it has the right sensitivity (83.1%), specificity (81.8%), and positive predictive value (95.3%) .
Strategies to implement CPGs
CPGs will only be useful for professionals and patients if their recommendations are incorporated to regular clinical practice. Achieving this is a complex process in which several factors play a role [26, 27].
To increase the use of the guideline, its distribution and implementation strategy must be planned very carefully. As a first step, the identification of the barriers and facilitating factors, adapting all strategies to the setting in which the CPGs will be used, is fundamental [28–30].
Several CPGs implementation strategies have demonstrated their effectiveness. Some authors group these interventions depending on whom they are addressed to: physicians and patients, communities or the general population, or health centres and/or health systems .
The Cochrane EPOC (Effective Practice and Organization of Care) group proposes to classify interventions into four categories: professional interventions (such as distribution of educational materials or educational meetings); financial interventions (such as fee-for-service or prospective payment); organisational interventions (such as creation of clinical multidisciplinary teams) and regulatory interventions (any intervention that aims to change health services delivery or costs by regulation or law) .
The Grimshaw et al. review evaluates the effectiveness and cost of different clinical practice guideline dissemination-implementation organizational strategies. This study takes into account the impact on professionals as well as on patients. It includes 235 studies (between 1966 and 1998) and 309 comparisons. Among the results, it is worth noting that most implementation strategies improved adherence to CPGs. Simple strategies, such as reminders, increase adherence by 14.1%. The distribution of educational materials improves this by 8.1%. Educational programmes, almost always as components of more complex interventions, improved practice by 6%, and audits and feedback by 7%. The complexity of the strategies and the mixture of interventions did not improve results. In their conclusions, it is noted that there is little evidence about which strategies can be more effective in each situation. The authors consider that there is a need to develop and validate theoretical models for behavioural change, as well as to investigate the efficiency of the strategies in the presence of different barriers and factors that can modify effectiveness.
We consider it fundamental to put into effect organizational strategies that will enable us to use the guideline and apply its recommendations, as well as to measure and evaluate the impact that implementation of the CPGs will have on professionals modifying their practices, and improving outcomes for patients [34, 35].
There are two reasons for using cluster randomised trials design: to evaluate the group effect of an intervention; and to avoid 'contamination' across interventions when trial participants are managed within the same setting.
The aim of the present work is to determine whether the use of a CPG implementation strategy (including training session, information, opinion leader, reminders, audit, and feed-back) for patients with anxiety disorders in primary care is more effective than usual diffusion in improving the score of the Goldberg anxiety scale at six and twelve months.
1. Evaluate the effectiveness of a CPG implementation strategy for the management of patients with anxiety disorders compared with the regular strategy, measured as the degree of suitability of the treatments (psychological, pharmacological, et al.) received by patients.
2. Evaluate the effectiveness of a CPG implementation strategy for the management of patients with anxiety disorders compared with the regular strategy, measured as the percentage of patients who have received the information proposed in the guideline (oral or written) about their disorder.
3. Evaluate the effectiveness of a CPG implementation strategy for the management of patients with anxiety disorders compared with the regular strategy, measured as the degree of suitability of referral to mental health services, based criteria established in the guideline.
4. Describe the professionals' opinion about the usefulness of the CPG.
5. Evaluate the effectiveness of a CPG implementation strategy for the management of patients with anxiety disorders compared with the regular strategy measured as a change in the patient's quality of life.