Our results indicate that self-reported intent to continue if experiencing side effects and intent to continue even with a lack of initial efficacy are very good markers for attrition. A substantial percentage of participants were willing to express concern or ambivalence at baseline about continuing to attend with side effects (36%) or lack of efficacy (23%). An uncertain/negative response to either of these questions at baseline and at week 2 predicted attrition, with improved prediction at week 2 for both questions.
Since 58% of the patients experience at least moderate side effects as early as 1 week after SSRI initiation [37
], this improved prediction at week 2 with either the side effect or lack of improvement question may be due to participants basing their retention predictions on actual experience with side effects with the current treatment and/or a beginning perception of the drug's efficacy.
Since only 2–4% of the participants expressed a negative or uncertain intent to continue with treatmentwhen asked the more general questions (i.e. likely to attend next visit, likely to complete 8 weeks), questions addressing specific concerns as opposed to general ambivalence aremore likely to be useful in clinical practice. Participants may have good intentions at treatment initiation to complete treatment or may be concerned about disappointing their clinicians by expressing a general lack of commitment. Patients who actually experienced side effects prior to dropping out were more likely, at baseline, to have reported an uncertain/negative response about continuing with side effects. Even more strikingly, however, dropouts who did not report side effects were still twice as likely at baseline and 3 times as likely at week 2 to have reported they were uncertain or negative about continuing treatment. In addition to predicting attrition, uncertain or negative responses to the question about continuing to attend if not improving were also associated with a meaningfully lower rate of symptom improvement in both dropouts and completers. This result may be similar to studies that found positive expectations of treatment effectiveness to be associated with improved treatment outcomes in depression [38
] as well as a possible mechanism in the placebo effect [41
It is important to resolve adverse events that occur early in treatment [37
] and maximize the chances of rapid efficacy with aggressive treatment [42
] to help reduce attrition. It is even more proactive, however, to inoculate patients who directly express concerns or ambivalence against discontinuation. Uncertain/negative intent to continue with side effects or lack of efficacy may reflect concern about the treatment's possible harmfulness, consideration that depression is not serious enough to tolerate side effects, lack of awareness of the time needed to reach remission, prior negative experiences with side effects or any of a host of other possibilities. However, a noncommittal statement from a patient about continuing in treatment generally, or in the context of side effects or lack of treatment efficacy, is an excellent signal that indicates a potentially less resilient patient. With these patients, it may be helpful for clinicians to conduct an individualized review of patient-specific thoughts regarding side effects and lack of efficacy as well as other concerns about treatment or medication to personalize the focus of educational efforts.
There is evidence that such inoculation may be helpful. Studies have found that patients who discussed adverse events with physicians or pharmacists at the initiation of therapy and those told to continue medication for at least 6 months were less likely to discontinue antidepressant treatment [6
], and patients told by their clinician that they might not see a benefit for 2–4 weeks were more likely to be taking their antidepressants 1 month into treatment [4
]. These interventions may have modified patient beliefs or their intent to continue, or both. Studies of collaborative care or educational interventions indicate that the provision of educational or supportive interventions that can address topics such as what to do about side effects or the time expected to reach remission may be useful in improving adherence or persistence in taking medications as well as outcomes [4
]. Personalized responses to each patient's own expressed concerns may be even more useful in retaining less committed, at-risk patients in treatment for a sufficient time to maximize the chances of reaching and sustaining remission with this often chronic or recurrent illness.
The current study has several limitations that may affect its generalizability. The participants received monitored dosing of medications while a CRC supported both clinician and patient. Side effects may not have been identified if they occurred following a visit but prior to dropout. Symptom improvement for completers and dropouts was based on the last available measurement occasion. Data about prior treatment experience were not available. We do not have retention data beyond 8 weeks. Some comparisons had small numbers, making generalizing from the findings difficult. The current study also did not address factors related to clinicians (e.g. experience), clinics (e.g. access and availability of appointments), medication (e.g. complexity of the regimen) or participants (e.g. specific beliefs or attitudes about medication or treatment).
In summary, questions regarding intent to attend future antidepressant treatment visits in the context of side effects or lack of efficacy may be useful clinical tools. They may identify patients with concerns about these issues, as well as patients who may be less resilient to the challenges of completing a course of treatment or have other specific concerns that can be addressed. An individualized review of patient concerns and the individualized tailoring of educational or other interventions may reduce attrition and increase the chances for remission.