Serotonin imbalances in the brain have become a popular explanation for depression, anxiety, and OCD. The understanding of serotonin’s role in mental health even helped demystify and de-stigmatize depression and anxiety disorders. Many individuals began to take solace in the fact that chemical imbalances meant those mental health difficulties did not indicate some personal flaw.
That solace is a valid advantage of the serotonin hypothesis. Behavioral science has long established that mental health difficulties are not due to shortcomings. But the role of serotonin in these mental health difficulties has been the subject of great debate in the last few years.
The serotonin hypothesis posits that the amount of serotonin in one’s brain has effects on mood, sleep, and sexual desire, among other functions. Theory says selective serotonin re-uptake inhibitors (SSRIs) improve mental health by allowing more existing serotonin to sit between brain cells for longer. This creates a greater chance that neighboring brain cells will catch more serotonin and increase its transmission throughout the brain. (Note that SSRIs do not produce new serotonin).
SSRIs have also shown benefit for depression, anxiety, and obsessional processes in conditions like OCD or OCPD. Interestingly, however, this neurological process was initially only a hypothesis. This hypothesis draws support from the effectiveness of SSRI’s on mental health. But research has not directly linked the role of decreased serotonin to these mental health conditions.
Whaaaaaaattt??
Something else could be going on “under the hood”. A 2023 study reported multiple meta-analyses on a large body of serotonin studies. These analyses showed no associations between genes related to serotonin and depression, or with serotonin itself and depression. The review also found that deficits in how serotonin bonded to nerve cells was only loosely associated with depression, at best.
This study set off a huge debate among psychiatric researchers. A subsequent review highlighted research supporting serotonin’s role in mental health.
In many ways, this debate is not settled. And many patients swear by the benefits of SSRIs. Some even assert these medications quite literally save lives. On the other hand, the Trump administration initiated an investigation of SSRIs. RFK Jr. has also spread misinformation about SSRI side effects.
Something about them may be working. But why SSRIs show benefits is the major question here. Many now think of depression, anxiety, and OCD as from “just a serotonin imbalance”. Therefore, it is strange that a direct link between SSRIs and mental health is still not fully understood. So for now, grains of salt….
Either way, non-prescribing therapists can continue to utilize a range of existing psychosocial resources for depression. CBT, behavioral activation, ACT, exposure therapies, exposure and response prevention (ERP) for OCD, and other evidence-based approaches effectively target depression and anxiety, either alongside medication or on their own. Newer treatments for treatment-resistant depression (e.g., TMS, ketamine, and some psychedelics) are also promising updates to target depression when used along with psychotherapy.
So for now, therapists keep working with the resources they have. Continued research on SSRIs may shed more light on how they work and could yield new effective medications.
