Here’s the news summary she referenced:
Little evidence that chemical imbalance causes depression, UCL scientists find, The Guardian, 20 July 2022

Scientists have called into question the widespread use of antidepressants after a major review found “no clear evidence” that low serotonin levels are responsible for depression.
…
“Many people take antidepressants because they have been led to believe their depression has a biochemical cause, but this new research suggests this belief is not grounded in evidence,” said the study’s lead author, Joanna Moncrieff, a professor of psychiatry at University College London and consultant psychiatrist at North East London NHS foundation trust.

“It is always difficult to prove a negative, but I think we can safely say that after a vast amount of research conducted over several decades, there is no convincing evidence that depression is caused by serotonin abnormalities, particularly by lower levels or reduced activity of serotonin.

“Thousands of people suffer from side-effects of antidepressants, including the severe withdrawal effects that can occur when people try to stop them, yet prescription rates continue to rise. We believe this situation has been driven partly by the false belief that depression is due to a chemical imbalance. It is high time to inform the public that this belief is not grounded in science.”
…
Most antidepressants are selective serotonin reuptake inhibitors (SSRIs), originally said to work by correcting abnormally low serotonin levels.

The review, published in the journal Molecular Psychiatry, looked at studies examining serotonin and depression involving tens of thousands of people. One of the findings was that research comparing levels of serotonin and its breakdown products in the blood or brain fluids did not discover any difference between people diagnosed with depression and healthy people.

The authors also looked at studies where serotonin levels were artificially lowered in hundreds of people and concluded that lowering serotonin in this way did not produce depression in hundreds of healthy volunteers.

Other studies looked at the effects of stressful life events and found that the more stressful life events a person had experienced, the more likely they were to be depressed, showing the importance of external events.

According to the research, there is also evidence from other studies that antidepressants may actually induce low serotonin in the long term.
…
“We do not understand what antidepressants are doing to the brain exactly, and giving people this sort of misinformation prevents them from making an informed decision about whether to take antidepressants or not.”

Here’s the actual study:

The serotonin theory of depression: a systematic umbrella review of the evidence, Nature: Molecular Psychiatry, 20 July 2022

From the abstract:

The main areas of serotonin research provide no consistent evidence of there being an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations. Some evidence was consistent with the possibility that long-term antidepressant use reduces serotonin concentration.

This is a watershed moment. No matter how hard the pharmaceutical companies fight this, and boy-oh-boy you can bet they will, there’s no going back. Depression is not caused by a “chemical imbalance”. A lot of it is caused by our reactions to our environment.

I’m sitting here thinking … I don’t understand how people who work for pharmaceutical companies can advance these drugs knowing they don’t work, giving people a false sense of hope, not caring if they suffer or lose their lives. What is the return for them? Money? It has been 35 years of lying (Fluoxetine/Prozac by Eli Lilly was FDA approved in 1987, thought to be the first SSRI marketed) to enrich themselves at other’s expense. This is deeply disturbing.

It is also disturbing, depressing if you will, that people continue to give it over to drug companies, to trust them, instead of believing the science, the evidence … instead of listening to that small still voice in their head, that urge from their heart, to go with their curiosity, to question these people if something feels off.  It’s like … the drug has become a surrogate for love in a loveless society … and people are lining up for it.