A Cohort Study of Adherence to Antidepressants in Primary Care: The Influence of Antidepressant Concerns and Treatment Preferences
Prim Care Companion J Clin Psychiatry 2007;9(2):91-99
© Copyright 2015 Physicians Postgraduate Press, Inc.
Objective: Clinical guidelines recommend
that antidepressant treatment should be continued
for a minimum of 6 months following response in depression and anxiety disorders. However,
adherence to antidepressants is low. This prospective cohort study investigated the
influence of patients' antidepressant concerns,
treatment preferences, and illness perceptions on
adherence to antidepressants over a 6-month period.
Method: A cohort of 178 patients aged 18
to 74 years and newly issued with a prescription
for antidepressants to treat any condition was followed up prospectively at 5 primary care
practices in Southeast England. Adherence was measured through self-report and prescription
refill data. Patient perceptions were quantified
using validated outcome measures, the Beliefs
about Medicine Questionnaire and the Illness
Perception Questionnaire, at 4 timepoints. Patient
treatment preferences were recorded using a
specially designed questionnaire. Data collection
took place between September 2000 and May 2002.
Results: Of 147 participants (83%) who
completed the study, 19% persisted with antidepressants in accordance with guideline
recommendations throughout the 6-month period. Specific concern about antidepressant side
effects (OR = 3.30, 95% CI = 2.20 to 4.97) and
general worry about taking antidepressants (OR =
1.65, 95% CI = 1.13 to 2.40) were independent
predictors of antidepressant nonuse. Preference for
different treatment/uncertainty about preferred
treatment was also a strong predictor (OR = 3.82,
95% CI = 1.35 to 10.77). However, illness
perceptions were not associated with adherence.
Conclusions: Concerns about
antidepressants and a mismatch between patients' preferred
and prescribed treatment act as significant barriers
to sustained adherence. This study highlights the central role of the patient-physician partnership
in exploring antidepressant concerns, working with treatment preferences, and providing
supportive continued management. The findings may
inform the development of interventions within
primary care programs to enhance commitment to
treatment for common mental disorders.