Psychology Studies - Mood Disorders

GERSHON

• studied those with depression
• and their family histories

• states that those with a genetic history are three times more likely to develop depression
• in comparison to those who don't

SUGGESTS A GENETIC CAUSE OF DEPRESSION

WILHELM

• studied the effect of genes on the chances of depression development 
• examined a gene called the 'serotonin transporter'
• states that, when this is faulty, the chance increases
• this gene is inherited 

SUPPORTS THE INFLUENCE OF GENETIC HEREDITY ON DEPRESSION

McGUFFIN ET AL.

• studied the concordance rates of unipolar depression within twins 
• 68 monozygotic twins
• 109 dizygotic twins

• 68% concordance rate between monozygotic twins
• 20% concordance rate between dizygotic twins

EMPIRICAL EVIDENCE TO SUPPORT THE INFLUENCE OF GENES ON THE DEVELOPMENT OF DEPRESSION - MONOZYGOTIC TWINS SHARE 100% OF THEIR GENES!

SHASTRY

• observed the levels of neurotransmitters within bipolar depression sufferers

• high levels of norepinephrine & low levels of serotonin during the manic phase
• low levels of both norepinephrine & serotonin during the depressive phase

SUPPORTS THE EFFECT OF NEUROCHEMISTRY ON DEPRESSION. SUPPORTS WALLACE ET AL.'S STUDY ON THE SEROTONIN TRANSPORTER.

SHASTRY

• observed the levels of neurotransmitters within bipolar depression sufferers

• high levels of norepinephrine & low levels of serotonin during the manic phase
• low levels of both norepinephrine & serotonin during the depressive phase

SUPPORTS THE EFFECT OF NEUROCHEMISTRY ON DEPRESSION. SUPPORTS WALLACE ET AL.'S STUDY ON THE SEROTONIN TRANSPORTER.

SOUTHWICK ET AL. 

• studied the levels of cortisol within depression sufferers 
• this is a hormone produced in stressful situations
• levels of this were found to be permanently high in depression sufferers

SUGGESTS AN INFLUENCE OF NEUROCHEMISTRY ON THE DEPRESSION

but can we establish cause & effect?

SELIGMAN 

• developed the theory of learned helplessness
• he states it to occur in 3 stages:

1. uncontrollable negative events occur

2. this leads to feelings of complete loss of control

3. which makes a person feel permanently helpless, guilty and depressive

SUPPORTS THE THEORY THAT DEPRESSION IS A LEARNED DISORDER

But doesn't everyone experience negative events they can't control? This does not always lead to depression.

SWANN ET AL. 

• conducted a study where he told people who viewed them negatively and who didn't
• those suffering with depression chose to spend time with those who viewed them negatively
• Lewinsohn's study in 1974 gives reasoning for this

SUPPORTS THE THEORY THAT DEPRESSION IS REINFORCED BY ENVIRONMENTAL INFLUENCES

SELIGMAN (2)

• placed dogs in a box that administered painful electric shocks
• ensured they could not escape
• later placed them in a box that administered electric shocks they could escape from
• they made no effort to escape
• develops & supports his 3-step theory of learned helplessness

SUPPORTS THE THEORY THAT DEPRESSION IS LEARNT FROM ENVIRONMENTAL INFLUENCES.

but how do we know the dogs didn't just believe they had been placed in the same box?

LEWINSOHN'S 6-STEP THEORY

1. a person experiences loss

2. they now have less positive reinforcement in their lives

3. they person withdraws from a social life

4. depression occurs as a result

5. other give empathy and attention, which reinforces depressive behaviour

6. the person continues the symptoms to recieve reinforcement from others

BECK 

• used the dysfunctional attitude scale (DAS)
• group of depression sufferers
• group of non-sufferers

• sufferers scored higher on the test that non-sufferers
• shows they think in more dysfunctional and negative ways 

SUPPORTS THE COGNITIVE THEORY, SUGGESTING THAT NEGATIVE THOUGHTS INFLUENCE NEGATIVE BEHAVIOUR.

but how can we establish cause or effect?

ROTH & KUBAL

• conducted a study to test Seligman's 'learned helplessness'
• gave questions that were impossible to answer
• the participants could not answer
• they were then given easier questions, which could be answered

• they took longer to answer after recieving the harder questions

DISPLAYS THE PROCESS OF 'LEARNED HELPLESSNESS'

HENRIQUE & DAVIDSON

• studied the brains of sufferers and non-sufferers
• found that there was hypoactivation in the pre-frontal cortex of the sufferers
• he could not find this in the brains of the non-sufferers

THIS SUGGESTS AN OBVIOUS ANATOMICAL LINK TO THE CAUSE OF DEPRESSION, ALTHOUGH IT IS HARD TO ESTABLISH CAUSE AND EFFECT