Falling out of depression — does psychological therapy reverse the biological changes in depression?
A few months ago, I wrote a blog on how the experience of early life stress can, at times, lead to changes in our immune system and neuronal processes, ultimately resulting in depression. I focused on depression in adolescence because often, first symptoms begin long before adulthood and I wanted to understand what biological and environmental factors can make a young person prone to developing depression. Answering these questions is important to me because they shed the light on ways to prevent or minimise experiencing depression among adolescents.
This, however, is only one side of the coin.
Like me, you might ask, but what if we can’t always act timely to prevent the onset of depression? Well, you might seek treatment, that being either antidepressant medication or psychological intervention, or both.
The current National Institute for Health and Care Excellence (NICE) guidelines recommend psychological therapy as a first choice of treatment for adolescents with depression. And this, my reader, is the other side of the coin that I was also interested in - what happens, biologically, when a person with depression undergoes psychological therapy?
Can we see biological signatures of recovery following psychological intervention?
I am a postdoctoral mental health scientist, specialising in the neuroscience of depression. Last year, I received an invitation from the scientific journal — Brain, Behaviour and Immunity-Health, to write a single author scientific article for their special issue, where I had the freedom to choose the topic of interest. Without a moment of hesitation, I took up this excellent opportunity and decided to write about the topic I am passionate about- the biology of how depression unravels and how it dissipates with the help of psychological therapy.
As I already talked about the biology of falling into depression in adolescence in my previous blog, here, I will focus on the “other side of the coin” — the biology of falling out of depression following psychological therapy.
Psychological therapy
Let’s start with the basics! Psychological therapy is a talking therapy, which is prescribed for common mental health problems across all ages. There are different types of psychological therapies which are tailored based on the individuals’ needs. In England, such treatments are available on the NHS and privately, and they must be delivered by an accredited professional, meaning that the therapist has received professional training and was certified by an officially recognised institution within a country, such as the British Association for Counselling and Psychotherapy, British Association for Behavioural and Cognitive Psychotherapy, or British Psychoanalytic Council, to name a few in the UK. It is always good to inquire about the therapist’s credentials before starting therapy.
For adolescents with symptoms of mild depression, the first choice of treatment includes either of the following types of therapy: cognitive behavioural therapy (CBT), group interpersonal therapy (IPT), group non-directive supportive therapy (NDST) and attachment-based family therapy. If symptoms of depression persist, other forms of therapy are explored including brief psychosocial intervention (BPI), psychodynamic psychotherapy, or family therapy. Lots of fancy words, I know! So, let’s understand their meaning.
Starting with the most widely practised therapy — CBT, which focuses on challenging the person’s thinking patterns, emotions, and behaviours. It tends to be short term, e.g., up to 3 months in treating mild symptoms of depression in adolescents. Other types of therapy may focus on more in-depth interpretation of the emotional states including exploration of past experiences, such as psychodynamic approaches and these tend to last longer, e.g., 30 weekly sessions in adolescents. Lastly, there are approaches that focus on relationships with others such as family therapy or IPT, or more directive approach such as BPI which includes psychoeducation and is task-oriented, i.e., guidance on building new skills and habits.
Rebuilding the biology with psychological therapy
Most studies that look at the biological changes in relation to psychological therapy focus on brain functioning. The most commonly investigated type of therapy is CBT.
Both, studies in adults and adolescents suggest that psychological therapy leads to changes in the same areas of the brain which are initially involved in depression development. For example, lower activity of the “reward system” — part of the brain which is less responsive to positive information in depression, becomes more active following a successful course of CBT. We also see changes in the activity across areas of the brain involved in emotional processing and executive functions such as decision making, social and emotional regulation or planning which are commonly affected in depression. These findings suggest that some of the biological changes seen in depression can be reversible with therapeutic help.
We also see involvement of cortisol, a stress hormone, in the recovery from depression. In some people, including adolescents, chronic higher levels of cortisol are linked with depression. One study showed that better improvement following psychological therapy in adolescents with depression was linked with lower levels of cortisol. Top that up with the results from a meta-analysis — a synthesised analysis of the results pooled from many studies — which showed that higher levels of cortisol predicted worse treatment response to CBT in adults with depression, we are beginning to see a pattern.
We also know that psychotherapy affects the chronic low-grade inflammation seen in depression, although the extent of this knowledge is still limited. For example, one meta-analysis showed that psychological therapy led to lower levels of c-reactive protein (CRP), a substance produced in inflammation. However, another meta-analysis did not find psychological therapy to have any effect on CRP levels. It’s as if you were comparing apples and oranges.
Coming back to my initial question — can we see biological signatures of recovery following psychological intervention? Yes, we can and you can read more about it in my recently published article. However, we do need more studies, particularly in adolescence, as these are falling short compared to the studies in adults. Nevertheless, these are very exciting findings and yet another example of how mind and body work together, not only in developing illness but also in recovering from it.
