I'm happy to be a member of an online community where some intellectual forum discussions are generated. In this setting, a question was posed to me pertaining to the relationship between negative thinking and serotonin from Scott in Auckland. Since other people may be curious about the same topic, I thought I'd post my response here.
I absolutely love this question! The interplay between what we do as psychologists and biology is one of my favorite topics. How we are trained through all of our collective learning experiences to think - and more specifically, appraise, evaluate, and interpret - has a direct effect on our physiology and biology.
For those of you not familiar with Cognitive Behavioral Therapy (CBT) it involves very active Socratic questioning on the therapists part about thoughts the patient currently has. This type of therapy is in stark contrast to old-fashioned Freudian type therapies that mainly just involve combing over events of your past. If a patient comes into my office and says "I'm a loser," my response would be "Oh, yeah? It must stink to think that. But what is the evidence that you're a loser?... Have you ever won anything?... Even if you are a loser now - whatever that means - will you always be a loser?" etc.
After all this questioning, we usually end up laughing together about what I ridiculous statement "I'm a loser" really is and how true it can feel. Through this process, the rift between what our mind thinks and what is actually true is created. After the initial separation between thought and belief is fostered, we go come up with rational responses to these types of negative automatic thoughts like "I'm a loser" and practicing mentally rehearsing the rational responses as homework.
So, that is a brief description of the cognitive piece of cognitive-behavioral therapy. Interestingly, the behavioral piece has been shown to be more effective than the cognitive piece at changing the interpretation of thoughts. Let's take, for example, someone who has social phobia. You can tell them that their phobia of talking to other people is silly all you want, but they still may not believe you. The best thing to do is act.
We start small. I might grab the secretary into the therapy room and ask her to have a 5 minute conversation about something like traveling with the patient. After five minutes, the secretary says it was lovely chatting and leaves. Now, that wasn't so bad was it?
Then as homework assignments, the patient is to engage in social activities, starting with a small anxiety producing task, and working their way up to doing something very scary like public speaking, over the course of weeks. In this way, their own thoughts are directly challenged by the outcome of their behavior. They always think it will be worse than it ends up being. In this way, they engage in little "behavioral experiments" that directly test their maladaptive beliefs.
It is worth noting here that while the behavioral piece has been shown to be more effective, people may not be willing to engage in the behavioral piece without both a strong rationale for it. It is my opinion that going through the cognitive part of the therapy and disputing thoughts that automatically pop up is an extremely useful first step that must be taken with a vast majority of people before jumping into the behavioral piece. In fact, a client of mine expressed this sentiment completely of her own accord to me today.
While we have discussed both the cognitive and the behavioral piece at this point, there is a third very important piece that changes our relationship to our thoughts - Eastern mindfulness practice. Learning to be aware of our thoughts and release the less useful ones is extraordinarily helpful as well. As a side note, I practice letting go of thoughts every day during yoga, which I use as a moving meditation more than exercise. '
I'll talk more later about integrating these components of treatment, but for now, back to your question! There have been many studies showing that CBT is as useful as treating depression as antidepressants; however, CBT has the added effect of continuing to work even after treatment ends. In terms of whether or not it increases serotonin in the synapse, there are huge ongoing clinical trials in the U.S. examining this right now. So far the evidence points that learning to regulate your emotions through these types of treatments does effect serotonin.
Here's a link to clinical trial information.