Exploring and Examining Antidepressant Prescribing and Doses used in Primary Care, in Scotland, to Treat Depression

Abstract

Background: Antidepressant prescribing continues to rise. Selective serotonin reuptake inhibitor (SSRI) use, increased long-term prescribing, and higher doses are contributing to current growth. The majority of antidepressants are prescribed to treat depression.

Aim: To explore and examine the use of SSRI doses and dose-response effects for the treatment of depression, for adults, in primary care.

Method: An inter-related three study approach was used. A cross-sectional quantitative analysis exploring patient-level factors associated with prescribed daily doses of SSRIs. A qualitative interview study exploring what influences GPs’ use of specific antidepressants and doses. Lastly, a systematic literature review of reviews examining SSRI dose response-effects for efficacy, acceptability and tolerability for acute phase (≤12 weeks) treatment of depression.

Results: The quantitative analysis found that higher SSRI doses were significantly associated with, in descending order of magnitude, individual practice attended, being prescribed the same SSRI for ≥2 years and living in a more deprived area.

GPs’ treatment of depression involved ethical and professional imperatives of ‘doing the right thing’ for individuals by striving to achieve the ‘right care fit’. Factors influencing prescribing and doses varied over time from first presentation, to initiation and longer-term treatment. Many were unaware that higher SSRI doses lacked greater efficacy, and onset of action occurred within 1-2 weeks; preferring to wait 8-12 weeks before altering treatment. Ongoing pressures to maintain prescribing, few perceived continuation problems and lack of proactive medication review, all combined to further drive prescribing growth over time.

Forty-two reviews met inclusion criteria. The majority indicated that SSRIs demonstrated ceiling effects for efficacy; standard doses being non-inferior to higher doses. Higher doses were associated with more adverse events.

Conclusion: Although GPs strive ‘to do the right thing’ to help people, better promotion of SSRI dose limitations may help to optimise patient care, reduce prescribing and avoidable ADEs.