In 2003, a total of 29,517 (8.6 %) individuals were dispensed at least one antidepressant unit from pharmacies in the Lleida Health Region. Of the patients who started treatment with antidepressants in 2003, 12.5 % remained in treatment after 4 years. The mean age of patients was 54 years (SD: 17.82).
According to some reports, one-third of patients with depression present episodes or symptoms for more than 2 years [21]. Other patients present recurrences and require chronic medication.
In our population, anxiety disorders accounted for 25 %, mood disorders 19 %, mixed disorder in 7 %, and in 49 % no diagnosis was recorded. The descriptive approach based on the diagnostic criteria of the CIE-10 [22] and the DSM-IV [23] has improved the identification and treatment of mental disorders worldwide. However, even the creators of these systems recognize that their main achievement has been to improve diagnostic accuracy [24]; there is growing concern among experts that the clinical utility these diagnostic criteria may be seriously limited [25]. Several major problems have been highlighted in the literature. First, a high proportion of diagnoses of mental disorders are recorded as “unspecified” (the term used in ICD) or “not specified elsewhere” (the corresponding term in the DSM). This suggests that health professionals find the current categories difficult to use or imprecise for describing their patients, or do not find the nuances introduced by the diagnostic subtypes useful in their clinical practice. Second, a high proportion of people with mental health problems meet the criteria for two or more disorders [26].
Other studies have also reported problems with the diagnosis. The Netherlands Mental Health Survey and Incidence Study found that in around half of patients treated with antidepressants the diagnosis was not recorded [13]. Furthermore, between 10 % and 15 % of long-term continuous treatments with antidepressants were found to be no longer necessary. Conceivably, some patients may not have received a specific diagnosis because of the difficulty of coding certain poorly defined conditions in a situation in which the pressure on health staff is intense [27].
Thirdly, very often the same psychological or pharmacological treatment is effective for several different mental disorders [28]. One of the reasons for the limited clinical utility of current diagnostic systems is their extraordinary complexity and the inclusion, with each new review, of a greater number of categories with increasingly fine distinctions [26].
The most frequently prescribed drug during the early period (years 2003–2008) was paroxetine, followed by fluoxetine and sertraline. The most common prescription in the second period (2008–2011) was paroxetine, followed by escitalopram and then venlafaxine. A study conducted in Italy between 2000 and 2011 recorded an increase in the consumption of antidepressants and especially the group of selective serotonin reuptake inhibitors (SSRIs) [29].
The increase in the prescription of venlafaxine and escitalopram may reflect a policy of changing the active principle due to non-response to treatment. It is estimated that at least half of the people starting antidepressant treatment do not respond and a third remain depressed, despite the use of a variety of treatment strategies [21]. There has also been a change in prescription patterns on the part of physicians; a previous study reported an increase in the prescription of new molecules between 2002 and 2004 [30]. There is considerable commercial pressure on doctors to prescribe these new drugs, although this practice is not always justified by their clinical efficacy and safety.
Another reason for the increase in prescription of venlafaxine and escitalopram may be resistance to treatment. According to the clinical guidelines for depression, if treatment with SSRIs has proven ineffective, it can be replaced with venlafaxine, duloxetine or mirtazapine, and vice versa. If after a reasonable time no significant improvement is observed, an option would be to prescribe tricyclic antidepressants such as imipramine at doses of 150–300 mg/day [31].
Just over two-thirds of our patients (68.6 %) had received 1 or 2 antidepressant drugs at different times during the study period. The rest had consumed between three and thirteen different antidepressant drugs.
Overall compliance was 22 %. The compliance rate was 28 % in patients diagnosed with depression, and 21 % in those diagnosed with anxiety. The factors associated with increased treatment compliance were polypharmacy and a diagnosis of depressive or mixed disorder. The low overall rate of compliance may be associated with recurrences. It is known that recurrence risk in major depression is high; 50 % of patients have a new episode after the first one, 70 % after two, and as many as 90 % after three [32]. For this reason, an important question in the treatment of major depression is how long drug treatment should be maintained after recovery in order to prevent recurrence. Few studies have been specifically designed to address this issue and there is no clear consensus in the recommendations in other guidelines. In general, patients who abandon antidepressant treatment have a higher risk of recurrence than those who continue and, theoretically, patients with higher risk of recurrence would be the ones that would benefit the most from a prolonged treatment regimen [33]. Furthermore, the more prolonged the treatment, the smaller the difference in the risk of recurrence between treated patients and controls; that is, the benefit of extending treatment decreases over time [34]. Adjusting the duration of treatment after recovery to the type of patient is a considerable challenge and must be evaluated on a case-to-case basis.
Higher rates of compliance at older ages have been reported in some studies [35] which record shorter treatment periods in younger patients and in people in situations of socio-economic deprivation. However, in our study at multivariate level, compliance showed no significant differences with regard to age.
Among the various drugs prescribed, the highest compliance rates were observed with clomipramine, mirtazapine, maprotiline, and venlafaxine, and the lowest with paroxetine and trazodone. Other studies reported higher compliance with treatment with venlafaxine and duloxetine than with SSRIs, although this may be attributed to differences in clinical or pharmacological profiles. Serotonin reuptake inhibitors are used in first-line treatment with antidepressants. However, norepinephrine reuptake inhibitors are used in patients in more complex situations (i.e., recurrences or comorbidity) or in more severe cases [36].
Among the limitations of the data collection, the possible loss of some prescriptions should be borne in mind, because the drugs may have been dispensed over the counter or with prescriptions made by doctors outside the social security system. However, it has been estimated that these prescriptions account for a low percentage of the total in the health region; therefore, given the public health system’s universal coverage [37] the results of the survey can be considered valid. Furthermore, studies of this kind based on routine data bases lack information on cultural and social factors and on patients’ opinions, which also have an important bearing on the analysis of compliance. Another limitation is the lack of clinical information on the patients without a recorded diagnosis justifying treatment with antidepressants, and the absence of data regarding the severity of depression and patient response to antidepressants. It should also be borne in mind that we selected patients with an initial prescription in 2003 and who were prescribed antidepressant medication in 2008; we do not have information regarding their continuity over the intervening period or the number of episodes. This point should be considered when evaluating the results.
