Wednesday, April 24, 2013

EB2013 ASPET Blogging: Emotional and Motivational Deficits in Schizophrenia

Sushi. The best sushi restaurant ever is apparently very near the Boston Convention Center. You’re thinking about sushi now, aren’t you? Cool cucumber, spicy wasabi, salty soy sauce, and refreshing fish. Spicy tuna, salmon, snapper, tobiko, and eel. Yum. I’m getting hungry! But what does sushi have to do with schizophrenia?

Figure 1: Mmmm, Sushi (Source
Symptoms of schizophrenia are broken in two main categories: positive and negative. The positive symptoms are added qualities, such as hallucinations and delusions. The negative symptoms are subtracted qualities, a lack of pleasure in everyday life (called anhedonia) and flat affect (emotion is not shown in facial expressions or voice). There are also cognitive deficits, which include difficulty with working (short-term) memory and paying attention. Understanding negative symptoms is important for developing better treatments because current medications, called antipsychotics, don’t work well for the negative symptoms.

So where does sushi come in? Amazing sushi was Dr. Kring’s very effective example when explaining how emotion unfolds over time. Pretend we’re talking about the best sushi of your life. The emotional experience begins when you first think about something, in this case sushi. You get excited to eat sushi and you think about how delicious it’s going to be. As soon as you have a chance, you go out and get the sushi and you find it is, in fact, full of deliciousness. After eating, you savor the memory of how good it was, though this fades over time. The cycle begins again with the next item you anticipate, maybe seeing your significant other at the end of the day and bragging to them about how awesome the sushi you ate was. Dr. Kring hypothesized that, due to negative symptoms, people with schizophrenia would not anticipate pleasure, like anticipating the greatness of sushi, as strongly as the control group, but would enjoy pleasure in-the-moment as well as controls.

Figure 2: How emotion unfolds over time. Source: A.M. Kring and O. Elis (2013) Emotion Deficits in People with Schizophrenia., Annual Review of Clinical Psychology. 9, 409–433.
How do you test anticipation in a lab setting? It’s quite difficult because it’s tough to get study subjects excited enough about the things funding usually affords, like a piece of candy or a dollar. To study anticipation, it’s best if you can study the subjects during their daily life where they will naturally anticipate pleasurable events. So the next study used pagers to remind the subjects to complete a survey 7 times per day for 1 week. The survey included questions such as: What activity will you do later? How much pleasure do you think you’ll get out of this activity? Did you do the activity? How much pleasure did you actually get from the activity? The subjects answered the pleasure questions on a scale of 1 to 5 with 5 representing “no pleasure”.

The results showed that people with schizophrenia have no difficulty with in-the-moment pleasure; they report their level of enjoyment as the same as people without mental illness. However, people with schizophrenia anticipate the sushi to a lesser extent when compared with control subjects. They don’t feel as excited about it and their predictions about how much they will like it are not as strong as control subjects.

In fact, the control group tended to over-anticipate the pleasure they’ll get from an activity and it turns out this is true of the general population. It seems we’re constantly over-anticipating how wonderful the sushi will be and we’re always a little bit disappointed when we get it. The people with schizophrenia are actually spot-on with their anticipation when compared to their actual level of pleasure when compared within the schizophrenia group but what is actually being studied is the comparison between the control group and the group with schizophrenia.

The results of this study are important for assessment of the negative symptoms of schizophrenia. Dr. Kring was one of the creators of the Clinical Assessment Interview for Negative Symptoms (CAINS). The CAINS is a list of questions for health care providers to use when assessing patients for negative symptoms and diagnosing schizophrenia. The CAINS includes detailed directions for how to conduct the interview, which allows it to be given the same way by everyone who uses it; in other words, it’s standardized. This is great because we still rely on clinical assessment (interviews with patients) to make ratings of negative symptoms and assessments can vary from provider to provider. Having a standardized assessment procedure ensures people with the disorder will be diagnosed and treated and people without it won’t be treated in error.

P.S. If you have time left while in Boston, the sushi restaurant mentioned in the talk was: O Ya

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