Causes of death in mental health service users during the first wave of the COVID-19 pandemic: South London and Maudsley data from March to June 2020, compared with 2015-2019.

The COVID-19 pandemic is likely to have had a particularly high impact on the health and wellbeing of people with pre-existing mental disorders. This may include higher than expected mortality rates due to severe infections themselves, due to other comorbidities, or through increased suicide rates during lockdown. However, there has been very little published information to date on causes of death in mental health service users. Taking advantage of a large mental healthcare database linked to death registrations, we describe numbers of deaths within specific underlying-cause-of-death groups for the period from 1st March to 30th June in 2020 and compare these with the same four-month periods in 2015-2019. In past and current service users, there were 2561 deaths in March-June 2020, compared to an average of 1452 for the same months in 2015-19: an excess of 1109. The 708 deaths with COVID-19 as the underlying cause in 2020 accounted for 63.8% of that excess. The remaining excess was accounted for by unnatural/unexplained deaths and by deaths recorded as due to neurodegenerative conditions, with no excess in those attributed to cancer, circulatory disorders, digestive disorders, respiratory disorders, or other disease codes. Of 295 unexplained deaths in 2020 with missing data on cause, 162 (54.9%) were awaiting a formal death notice (i.e. the group that included deaths awaiting a coroners inquest) - an excess of 129 compared to the average of previous years, accounting for 11.6% of the excess in total deaths.