Science Interviews

Interview

Tue, 11th Nov 2014

The mental scars of cancer

Dr Emma Cahill, Cambridge University

Listen Now    Download as mp3 from the show Combating Cancer

Over time, more and more people are undergoing treatments for cancer and many are Depressionnow being cured, largely thanks to advances in modern medicine. But how does the diagnosis affect a personís mental state, even if they are cured, and are we paying enough attention to the problem? Emma Cahill is a Cambridge neuroscientist and spoke with Ginny Smith about the issue.

Ginny - Emma, are mental health issues, are they a serious problem for cancer survivors?

Emma -   Well, it seems that they're going to be more of an issue in the future because as we heard earlier, more people are surviving from cancers.  So, itís going to be important to actually consider this.  In the past, until like the late 1990s, a chronic illness wasnít even one of the criteria that they included to diagnose people with posttraumatic stress disorder which originally was called shellshock and it was typically associated with war veterans. 

But research groups that look into cancer like McMillan, their Report in 2013 found that of the 500,000 people living with cancer in the UK today, about 248,000 will develop mental health issues.  So, these include depression and anxiety but also posttraumatic stress disorder.

Ginny -   That's a huge number and is this the same kind of posttraumatic stress disorder that you see in war veterans and that kind of thing or is it a distinct kind of disease?

Emma -   Well, that's hard to know because there's been a lot less research done on PTSD in cancer.  But what we know is when itís being diagnosed, the same criteria are used.  So, in the first instance, they look that the symptoms are actually persisting for more than a month since the traumatic event occurred and the symptoms they look at are a heightened sense anxiety.  This can lead to poor concentration, trouble sleeping, and importantly, with posttraumatic stress disorder, something that's different from depression, is that they'll also have flashbacks or intrusive memories that are associated with the traumatic event.

Ginny -   So, with a traumatic event such as being in a war, being shot at, you can kind of see that thereíd be one trigger.  But I guess with cancer, itís a long period.  How would those flashbacks Ė would they be different?

Emma -   Yeah, but itís hard to know.  It could be coming as the forms of memories or nightmares and something you see quite often with posttraumatic stress disorder is an avoidance behaviour in the people suffering it.  And that's why itís a particular concern in the case of cancer patients because they could be avoiding treatments or seeing doctors or seeing people that they associate with their cancer symptoms.

Ginny -   Do you think itís something specific to cancer or do you think itís something about any kind of chronic disease that people may have recovered from?

Emma -   For the moment, we don't know if itís going to be anything specifically associated to cancer.  Itís beneficial to think of it in this context because itís a new way of looking at posttraumatic stress disorder.  The way itís conceptualised at the moment as a mental health issue is that itís a disorder of memory.  And particularly, memories that are emotionally intrusive and they cause a state of anxiety in the everyday life.  So, that could come from a traumatic event such as war, but also, from the pain associated with cancer treatments.  One thing we can see across different types of cancers is that a common feature that leads to posttraumatic stress disorder in a certain percentage of patients is the duration of treatment.  So, the longer treatment has gone on, further more likely they are to develop posttraumatic stress disorder.

Ginny -   So, are there certain types of cancer that are more likely to give you posttraumatic stress disorder than other types?

Emma -   That's not known at the moment.  So, people are looking into this most of the time by focusing on a specific cancer.  In certain cases, itís been suggested that childhood cancers might be more prone to posttraumatic stress disorder.  But that's also because the survivors obviously are younger, so they're surviving for longer.  So, you've got these confounding issues.  But as I said, one common feature is the duration of treatment seems to be key.

Ginny -   Now, you actually work on posttraumatic stress disorder itself and perhaps looking at treatments.  Is there anything we can do to help people who are suffering with mental health problems after surviving cancer?

Emma -   Definitely.  Well, the first thing that is positive about being aware of PTSD in the context of cancer is that itís going to provide more research avenues, so people will be looking at this with a more open view. 

At the moment, treatments include behavioural therapies, and meeting with therapists.  What they regularly try to do is to make people remember or relive their traumatic experience in a safe context, and to lose the sort of emotional potency that they associate with this.  That's also something that we look at in the lab as basic fundamental neuroscientists.  We look at how fear memories can be reactivated and then we try and find what brain chemicals are involved in that, and see, can we block them with specific drugs to try and neutralise the emotional part of the memory.  We don't want to ultimately wipe these memories, but just dampen them down so they don't have this emotional component that's the problem.

Ginny -   So, I imagine that's probably the last thing a cancer survivor wants to do, is relive those memories.  Why is that important if you are going to dampen down the emotions?

Emma -   Well, ití important because weíve known for a number of years that memories, once acquired by the brain are not just resistant and stored away like files in filing cabinet.  Once a memory is recalled, itís actually opened up again and what we call Ďde-stabilisedí.  So, in this stage, it can integrate new information and be updated.  So, by retrieving your fearful memory, you de-stabilise it.  in that instance, if you have interfering therapies, be there behavioural therapies or drugs, one of the ultimate goals for a lot of research right now is blocking the persistence of those damaging or fearful memories.  So, you'll retrieve them, they become de-stabilised and at that point, you use a therapy which will prevent them from persisting.

Ginny -   Quickly, you mentioned a drug that might be useful for this.  How long is it going to be before we have one that we can actually use to help people or is it already there?

Emma -   At the moment, there's no real drugs that can target the memory sides of PTSD.  Most people are treated with antidepressants or anti-anxiety drugs.  But research is really striving on to try and find particularly balance of the chemicals involved in the stress system such as adrenaline which not only has act on the body, but acts in the brain as noradrenalin.  So, there's a lot of focus on blocking the receptors for noradrenalin in the brain and trying to understand how that might be able to be a future treatment maybe.

Ginny -   Lots of promising ideas then.  Thank you.  That was Dr. Emma Cahil from Cambridge University. 

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