Two large studies comparing pre- and post-pandemic mental health in middle- and high-income countries returned opposite results.
As the pandemic dust finally begins to settle, two different portraits of the mental health effects are emerging.
In one, the population has been largely resilient, with only limited changes in general mental health and anxiety or depression symptoms.
In the other, probable depression and anxiety significantly increased during covid-19, especially among adolescents, pregnant or postpartum people and people who were hospitalised with the virus.
The opposing viewpoints are set out in two large, separate studies published on May 8 – one in the BMJ and one in Frontiers in Psychiatry – both of which compared mental health studies from before and after the pandemic.
The BMJ paper was a meta-analysis of 137 papers, representing 134 longitudinal study cohorts from high- or middle-income countries.
The problem with this is that you don’t have a LONGITUDINAL sample – there’s no pre-pandemic sample to compare to
— Health Nerd (@GidMK) March 9, 2023
This makes it very hard to know what changes were associated with the pandemic onset
The time window for pre-pandemic studies was between January 2018 and December 2019, and the post-pandemic dataset came from outcomes collected after January 2020.
In most cases, the post-pandemic outcomes were reported in the first six months of 2020.
All of the studies included cohorts which had retained at least 90% of the same participants over the two periods.
“Many analyses showed substantial heterogeneity, which suggests that point estimates should be interpreted cautiously,” the researchers wrote in the BMJ.
“Consistency did, however, exist across analyses in that most estimates of symptom changes were close to zero and not statistically significant, and changes that were identified were of minimal to small magnitudes.”
On a general population level, the only change was a “minimal” worsening of depression symptoms.
Broken down into subgroups, female participants were the only group that got worse across all outcomes, but only by a small amount.
Still, the authors were particularly concerned about this effect given that women tend to be the head of most single parent families, tend to earn less and are overrepresented in healthcare jobs.
“The small overall change in mental health symptoms suggests that many women have been resilient but that among some an important worsening of symptoms occurred,” they wrote.
“Indeed, although most of our analyses found no changes or minimal to small negative changes in mental health, they do suggest that the pandemic negatively influenced the mental health of some people, which is consistent with, for example, reports of increased visits for mental health and substance misuse.”
Older adults, university students and members of the LGBT+ community also had small upticks in depression symptoms.
There were three cohorts in the dataset that were assessed pre-covid, again in the first half of 2020 and a third time in late 2020 or early 2021.
In these studies, the third assessment was either stable or had improved in comparison to the early 2020 assessment.
The take-away from the BMJ study is that, rather than a mental health crisis, population-level mental health has held steady throughout the pandemic.
The Frontiers in Psychiatry article, meanwhile, looked at 108 pieces of research, 83 of which were meta-analyses.
All studies were published between mid-November 2019 and April 2022.
A meta-review of the meta-analyses found probable mental disorders appeared to increase during the pandemic, with narrative review evidence from the remaining 25 reviews suggesting a significant increase in substance misuse and suicidal thoughts.
The researchers acknowledge that these findings are at odds with previous research showing no evidence of increased suicide deaths, indicating that, while suicidal thoughts may have been on the rise, they did not necessarily translate into deaths.
Like the BMJ study, the authors identified women as being consistently associated with poorer mental health.
Younger people and students were also identified as an at-risk subgroup, but the Frontiers in Psychiatry authors were unable to come to a conclusion on whether it was a global effect or just in certain countries.
Japan, for instance, saw a 50% increase in student suicides in 2020, but two longitudinal studies from universities in Poland or Canada found no increases in suicidal behaviours among students.
“Given the substantial variation in findings in different geographic regions, at present there is low confidence in a global mental health impact on students, as differences identified in reviews may be due to other local factors,” the researchers wrote.
By identifying the population subgroups most at risk of adverse mental health outcomes during a pandemic – in this case women and students – the researchers believe that these groups could be better targeted in the even of a future pandemic.
