In a shocking twist, new research suggests that, despite common understanding, there is no direct link between serotonin (referred to as the happiness hormone) and depression.
Though depression can have many root causes, it’s often treated as a chemical imbalance (e.g., not enough serotonin). Previous randomized controlled trials with over 2,000 participants confirmed that SSRIs (selective serotonin reuptake inhibitors – a type of antidepressant medication) did reduce the risk of depression.
However, this new research from a large-scale review suggests otherwise.
This finding flies in the face of what has been widely believed and practiced for decades – many antidepressants prescribed are SSRIs, which are thought to improve mood by blocking the reabsorption of serotonin in the body, thereby increasing the amount of time serotonin can linger.
The new research combines all existing studies on the topic, with hundreds of thousands of participants, and found “no consistent evidence of there being an association between serotonin and depression or that depression is caused by lower serotonin activity or concentrations.”
Additionally, the researchers have “enough evidence to effectively rule out a link between genetic influences on the serotonin system and depression… serotonin genes aren’t linked to depression.”
Some studies tested the chemical imbalance theory by giving participants a drink that would decrease their serotonin, and most could not find a relationship between reduced serotonin and poor mood. Some studies could correlate a better diet with better mood but could not directly link it with serotonin levels.
Since the brain is malleable, some researchers even suggest that long-term use of SSRIs can decrease serotonin in the brain because the brain eventually stops producing it on its own.
Researchers emphasize that these recent findings do not necessarily mean that SSRIs and other antidepressants don’t work. Rather, it’s unclear how they work, as there may be many different mechanisms, chemicals, and processes at play that do not include increased serotonin levels.
Do not stop taking antidepressants if you are on them – always consult with your doctor before starting, stopping, or changing any medication.
A new review was conducted of data on sperm counts from around