Adults with mood and/or anxiety disorders have increased risks of comorbidities, chronic treatments and polypharmacy, increasing the risk of drug–drug interactions (DDIs) with antidepressants.

To use primary care records from the UK Biobank to assess DDIs with citalopram, the most widely prescribed antidepressant in UK primary care.

We classified drugs with pharmacokinetic or pharmacodynamic DDIs with citalopram, then identified prescription windows for these drugs that overlapped with citalopram prescriptions in UK Biobank participants with primary care records. We tested for associations of DDI status (yes/no) with sociodemographic and clinical characteristics and with cytochrome 2C19 activity, using univariate tests, then fitted multivariable models for variables that reached Bonferroni-corrected significance.

In UK Biobank primary care data, 25 508 participants received citalopram prescription(s), among which 11 941 (46.8%) had at least one DDI, with an average of 1.96 interacting drugs. The drugs most commonly involved were proton pump inhibitors (40% of co-prescription instances). Individuals with DDIs were more often female and older, had more severe and less treatment-responsive depression, and had higher rates of psychiatric and physical disorders. In the multivariable models, treatment resistance and markers of severity (e.g. history of suicidal and self-harm behaviours) were strongly associated with DDIs, as well as comorbidity with cardiovascular disorders. Cytochrome 2C19 activity was not associated with the occurrence of DDIs.

The high frequency of DDIs with citalopram in fragile groups confirms the need for careful consideration before prescribing and periodic re-evaluation.

Major depressive disorder (MDD) is a leading cause of disability worldwide, and yet delivery of care for this illness is rife with gaps. The COVID-19 pandemic has had far reaching implications for every facet of healthcare, and MDD is no exception. This scoping review aimed to ascertain the impacts of COVID-19 on the delivery of MDD care in Europe, as well as to evaluate any novel MDD care strategies trialled in this period.

We searched the PubMed and PsycINFO databases up to January 2022 with a strategy centred around COVID-19 and MDD. Full texts of eligible studies examining working-age adults and conducted in Europe were evaluated against several criteria. All outcomes were then extracted and a narrative synthesis was constructed to summarise identified themes.

Of 1,744 records identified in our search, 11 articles were eligible for inclusion in the review. In general, these studies reported a decrease in treatment rates, access to care, and perceived access to care during the COVID-19 pandemic. In addition, digital interventions trialled during the pandemic were broadly well-received by users, though their efficacy in improving MDD care was ambiguous.

Despite a limited number of pertinent studies, this scoping review identified a trend of exacerbated treatment gaps in MDD care during the pandemic. Several of our pre-specified gaps, including delays to detection or treatment of depression and rates of follow-up contacts, remained unexplored in the context of COVID-19. This highlights the need for further investigation to obtain a full understanding of the relationship between COVID-19 and MDD care in Europe.