Hi, anyone seen this recent Molecular Psychiatry paper also published in Nature?
www.nature.com
From their review of systematic reviews and meta-analyses published through 2020, authors conclude that, “it is time to acknowledge that the serotonin theory of depression is not empirically substantiated.”
I am personally open to considering this possibility, particularly given that “depression” does not have a singular cause. But the limitations of their review, some of which they acknowledge, are major. And I’m not sure how they can be so unequivocal in the conclusion that there is no support for the serotonin theory of depression given these major limitations - most of the studies in their review were low quality and had low power, and most of the studies did not account for the effects of antidepressant use.
In their words, “Most of the included studies were rated as low quality on the AMSTAR-2, but the GRADE approach suggested some findings were reasonably robust. Most of the non-genetic studies did not reliably exclude the potential effects of previous antidepressant use and were based on relatively small numbers of participants.”
I’m also curious how “depression” was defined across included studies and the impact of that on their findings. Depression in quotes given that the disorder (MDD) is not a single biological reality or construct.
Anyway, curious about others’ thoughts, implications, etc.

The serotonin theory of depression: a systematic umbrella review of the evidence - Molecular Psychiatry
The serotonin hypothesis of depression is still influential. We aimed to synthesise and evaluate evidence on whether depression is associated with lowered serotonin concentration or activity in a systematic umbrella review of the principal relevant areas of research. PubMed, EMBASE and PsycINFO...

From their review of systematic reviews and meta-analyses published through 2020, authors conclude that, “it is time to acknowledge that the serotonin theory of depression is not empirically substantiated.”
I am personally open to considering this possibility, particularly given that “depression” does not have a singular cause. But the limitations of their review, some of which they acknowledge, are major. And I’m not sure how they can be so unequivocal in the conclusion that there is no support for the serotonin theory of depression given these major limitations - most of the studies in their review were low quality and had low power, and most of the studies did not account for the effects of antidepressant use.
In their words, “Most of the included studies were rated as low quality on the AMSTAR-2, but the GRADE approach suggested some findings were reasonably robust. Most of the non-genetic studies did not reliably exclude the potential effects of previous antidepressant use and were based on relatively small numbers of participants.”
I’m also curious how “depression” was defined across included studies and the impact of that on their findings. Depression in quotes given that the disorder (MDD) is not a single biological reality or construct.
Anyway, curious about others’ thoughts, implications, etc.