Concerning drug prescription, this new paradigm has led to the introduction of the concept of "concordance" defined as "… an agreement between patient and health professional reached after a negotiation that respects the patient's beliefs and wishes to determine whether they want to be treated, when and how to take their medication, and recognizing that the patient's decision is the most important " [7]. In contrast with traditional concepts such as "adherence" or "compliance" that reflect a paternalistic conception of the doctor-patient relationship based on a medical model of disease, concordance not only refers to the patient’s medication-taking behavior but rather the nature of the interaction between therapist and patient, based on the notion that consultations between clinicians and patients are a negotiation between equals, which aims to establish a therapeutic alliance [8,9]. In an attempt to operationalize this new construct, Raynor et al. [10] developed the scale "Leeds Attitude toward Concordance", a questionnaire designed to assess the attitudes of health professionals towards the concept of concordance, later adapted for use in patients [11].

Concordance is closely related to the more widespread concept of shared decision-making (SDM). This is a patient-centered approach in which the healthcare professional and patient exchange information on the best available treatment and discuss the implications of each option [12-14]. In the process, patient autonomy is respected, the patient is assisted with setting their values and preferences, and final treatment decisions reflect a mutual agreement between patient and physician rather than a unilateral decision taken solely by the physician. In this sense, concordance can be considered as the desired outcome of a SDM process [15], but it also has been conceptualized as a subset of SDM limited to the prescription of medications [16].

Trevena and Barratt [17] consider that the suitability of a decision in SDM depends on the clinical context, patient preferences, and the responsibility of healthcare professionals. However, not all patients are prepared, suitable, or want to participate to the same degree in the process of making decisions about the treatment of their disease. Some may want to play an active role in discussing treatment options, but ultimately want their doctors to be the ones who make decisions on their behalf. For this reason, healthcare professionals and health organizations should not assume that patients want to participate in clinical decision-making, but must assess each patient's preferences and tailor care accordingly.

Research on SDM has concentrated on the field of physical disorders, often in primary care [18,19]. SDM in patients with mental illness has received less attention, and studies are still rare as well as heterogeneous in their designs [20,21]. Studies reveal that most psychiatric patients want to be informed about their treatments and consequences, and that their preferences and values should be taken into account in the decision-making process about their treatments [22-26]. As regards mental healthcare professionals, available results also show a favorable attitude towards SDM, although with some nuances regarding patient characteristics (for example, a possible inability to make decisions) or the specific topic to which the decision relates (e.g., admissions). Intervention studies have applied SDM programs with the aim of improving concordance with psychiatric medications [27-29]. Numerous recent articles have highlighted the urgent need for more research in this area [30-32].

Concerning patients, previous studies have shown that although they are clearly in favor of being informed and that their views and preferences should be taken into account during the decision-making process, when asked who should be responsible for the final decision most of them prefer to delegate to the doctor [33]. This is reflected in the response to the questionnaire item 10 ("During the psychiatrist-patient consultation, it is the patient’s decision that is most important"), in which patients show their higher rate of disagreement, while for psychiatrists, although this item also registers the lowest rates of agreement, the percentage of agreement is more than double that corresponding to patients. This result has two not mutually exclusive implications: first, it suggests that the representation of a paternalistic doctor-patient relationship would be more rooted in the minds of patients than in professionals, contradicting the idea of health professionals as reluctant to lose their dominant role in their interaction with a patient who would prefer greater involvement in decision-making. Second, it suggests the need to develop theoretical models that differentiate between a process of deliberation between doctor and patient (characterized by mutual communication and empathy for the patient's feelings and values) and a final act of determining the decision to make [34,35]. In any case, concerning mental health professionals, we must not rule out a possible effect of social desirability, to the extent that participation and empowerment of the patient are now highly valued in the conceptualization of healthcare.

The only statistically significant difference between psychiatrists and psychiatry registrars was obtained in the aforementioned item 10, with registrars showing lower scores. It is possible to hypothesize that the wider experience of psychiatrists has provided them with a greater conviction of the importance of the patient's decision about treatment, perhaps in relation to medication adherence. However, none of the professionals variables assessed was significantly related to the attitude towards concordance.

Within the group of psychiatry registrars, women scored significantly lower on the total scale and it is not easy to find explanations for this result, especially when studies on the facilitation of SDM in consultation by the doctor found no statistically significant differences between the sexes [36,37]. In addition, the literature on doctor-patient communication shows women as more empathic and involved in collaborative behaviors and discussion of psychosocial topics [38,39]. However, a recent study in the context of SDM in primary care reveals that being female and registrar status are significant predictors of anxiety about the uncertainty in the treatment process [40], which could impair professional involvement in SDM. Finally, we obtained a difference with tendency towards statistical significance between those who work in hospitalization units compared to those who work in outpatient departments (lower scores in the former). This result could be accounted for because patients admitted usually have more serious conditions, which would imply a decline in the patient's decisional capacity, whether real or perceived by professionals.

From a psychometric point of view, there is a strong ceiling effect on the scores of the participants, especially in samples of professionals. This low variability may be responsible for the absence of significant relationships between attitude towards concordance and other variables considered. Future studies would analyze the functioning of LATCon scale compared to other measures of attitudes toward SDM, and explore the possibility of assessing such attitudes from a less abstract level, in order to identify more specific components in which more intense individual differences could be observed.

This study represents an initial attempt to analyze differences in attitudes to concordance between psychiatric patients and professionals in Spain, and it presents several limitations. First, samples may not be representative of Spanish psychiatric patients and professionals, especially this latter sample that was recruited at a psychiatry congress. Second, patients’ diagnoses were not collected because of confidentially issues, and therefore, responses between different diagnostic categories could not be compared. However, previous studies that include patients with different mental disorders did not obtain statistically significant differences between diagnostic categories [22,41], and mean scores on the Autonomy Preference Index (API - decision-making subscale) are quite similar across two studies that respectively include patients with schizophrenia [20] and depression [42]. Third, potential confounding variables such as social desirability or patients’ trust in the physician were not assessed.

Patient-centered psychiatry advocates a paradigm shift of attention to mental health problems, moving from a focus on diseases, typical of techno-medicine, to the humanization of care that facilitates patient cooperation because it considers the patient as the center of clinical care and considers their values and expectations, allowing the full integration of the psychological, behavioral, and social aspects of illness postulated by Engel's biopsychosocial model [43] based on systems theory. Our study demonstrates a positive attitude towards SDM in the field of prescription of psychotropic drugs in both mental health professionals as well as among psychiatric outpatients, but future studies need to be addressed in order to clarify to what extent this model, although apparently accepted, is always reflected in the daily practice of mental health professionals.