Group essay prep

The following activity is something that I do with my students to help them prepare for ERQs for Paper 2. The goal is to have them write an essay outline, but to really focus on the evaluation of a theory.  An explanation of the task is below, followed by two model responses.

The task

The goal of this task is to brainstorm and organize an essay response for the following question:

Evaluate one explanation of one disorder from the biological approach.

In order to do this, I have them write a response to one of the following more specific prompts:

  • Evaluate the Serotonin Hypothesis as an explanation of Major Depressive Disorder.
  • Evaluate the Cortisol Hypothesis as an explanation of Major Depressive Disorder.

To begin, have the students open this Google document. In order to use the document, they will have to make a copy and save it to their own drive.

Students should work in groups of 4 to 5 in order to complete the task. I allow them to use their notes and to discuss their strategies.  They will share their documents with me to give them feedback.  They are instructed to limit the amount of text and not to do any cutting and pasting.

Before they begin, we go over the notes on TEACUP at the bottom of the document.

Outline sample:  Serotonin hypothesis

What are the key assumptions of the theory that you are evaluating?

Low levels of serotonin are responsible for MDD.

A deficit in 5-HTT - the serotonin transport protein - is the primary cause of depression

Increasing levels of serotonin with SSRIs is a potential treatment for MDD.

Identify a study that supports the theory.  What are key descriptors of the study that you think must be in your essay?

Rausch et al (1985)

Participants given a serotonin antagonist - physostigmine or a placebo.

The drug condition reported feelings of depression.

What are two strengths of the study that you have chosen?

A true experiment with a double-blind control that allows for cause and effect.

Triangulation of data - self-reported as well as observed behaviour.

What are two limitations of the study you have chosen?

A feeling of depression is not the same as a diagnosis of MDD

The sample size was small - only 18

Identify a study that either supports or challenges the theory.  What are key descriptors of the study that you think must be in your essay?

Caspi (2003) studied the role of 5HTT

A linkage study & asked p's to fill in the Stressful Life Events survey.

Found that those with two short- alleles were more likely to develop MDD with 3 or more stressful life events; those with two long-alleles were more resilient.

How is this second study different from the first? 

The study is correlational.  It is also a larger sample size.  It is a more holistic approach - looking at both the role of the SERT and the environment.

What is actually “measured” in this theory?  How is it measured?

Levels of serotonin - through fMRI, neurotransmitter depletion (diet) or the use of SSRIs

Symptoms of depression:  self-reported data.

What does this theory fail to explain?

Although SSRIs immediately raise serotonin levels, improvement may take several weeks.

Cognitive symptoms of MDD - problems with memory, attention and decision making.

Cultural differences in symptoms.

Two other evaluation points of the theory.

Application:  SSRIs do not work for most people.

Evidence:  Caspi's research has not been consistently supported.

Outline sample:  Cortisol hypothesis

What are the key assumptions of the theory that you are evaluating?

MDD is the result of a hyper-active HPA Axis - that is, stress is the primary cause of MDD.

High levels of cortisol have a negative effect on the brain, leading to hippocampal atrophy and decreased serotonin, noradrenaline and dopamine activity.

Identify a study that supports the theory.  What are key descriptors of the study that you think must be in your essay?Adam et al (2010) - a sample of adolescents.  Measured baseline cortisol awakening response levels and then looked at depressive symptoms one year later.  Found a correlation between higher CAR and depression.
What are two strengths of the study that you have chosen?

Prospective, longitudinal

Large sample size.

What are two limitations of the study you have chosen?

Depressive episodes were self-reported and may not actually indicate MDD.

It is not possible to control for extraneous variables. The study was also only correlational in nature; cause and effect cannot be determined and it is unclear if depression leads to higher CAR or vice versa.

Identify a study that either supports or challenges the theory.  What are key descriptors of the study that you think must be in your essay?Videbech and Ravnkilde (2004) Meta-analysis.  Found a correlation between number of depressive episodes and the size of the hippocampus. Argues that cortisol has a negative effect on the hippocampus and thus emotional health and memory.
How is this second study different from the first? A meta-analysis - so a larger sample. Patients had been actually diagnosed.
What is actually “measured” in this theory?  How is it measured?

The baseline levels of cortisol - saliva and blood testing.

Depressive episodes - self-report and medical records.

Atrophy of the hippocampus/neurogenesis - MRI

What does this theory fail to explain?Only about half of all depressed patients have elevated glucocorticoid levels, so this theory cannot predict or explain all depression.
Two other evaluation points of the theory.

GR (glucocorticoid receptor) antagonists have been shown to be successful in the treatment of depression in some people.

The cortisol hypothesis explains symptoms that cannot be explained by other theories - eg. cognitive symptoms.

The role of stress on depression is highly documented, but the biological connections have not been understood.

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