Symptoms of a Major
Depressive Disorder

 Affective: guilt and sadness, lack of enjoyment or
pleasure in familiar activities or company.
 Behavioural: passivity
 Cognitive: negative thoughts, faulty attribution of
blame, low self esteem, irrational hopelessness,
difficulty concentrating, indecisiveness
 Somatic: lack of energy, insomnia or hypersomnia,
weight loss/gain, diminished libido.
Diagnosis of Depression

 When someone experiences two weeks of depressed
mood or loss of interest or pleasure.
 Diagnosis requires at least 4 additional
symptoms (such as insomnia, suicidal
thoughts, passivity, or difficulty
concentrating).
Facts about Depression

 Depression affects 15% of people at some time in
their life (Charney and Weismann 1988).
 Depression tends to be a recurrent disorder with
about 80% experiencing a subsequent episode.
 Depression is 2-3 times more common in women
than in men.
 It occurs frequently among members of lower socioeconomic groups.
 Levav (1997) found the prevalence rate to be above
average in Jewish males suggesting that some
groups are more prone to depression.
Serotonin & Depression

 Prozac: blocks the reuptake of serotonin thereby
leaving more serotonin in the synaptic gap/cleft.
 Serotonin is known to affect mood, emotions,
aggression, sleep and anxiety.
Noradrenaline &
Depression

 Another neurotransmitter called noradrenaline is
found to be correlated with depression.
 Janowsky et al. (1972)
 Participants were given a drug called physostigmine
(which lowers noradrenaline but increases
acetylcholine).
 They experienced feelings of self-hate and suicidal
wishes within minutes.
Cocktail of
Neurotransmitters?

 Rampello et al. (2000) found depressed patients to
have an imbalance of noradrenaline, serotonin,
dopamine (pleasure), acetylcholine (memory).
 Skeptics say that pinning depression to just
neurotransmitters is too simple and reductionist
(reducing complex behavior to a single factor).
Stress & Depression

 Cortisol: a hormone that helps us cope with stress.
 Cortisol hypothesis: Too much or too little cortisol
levels may predispose an individual to depression.
 Cushing’s syndrome: a disease which results in
excessive production of cortisol.
 There is a high prevalence of depression among
people with Cushing’s syndrome.

 Overproduction of cortisol may decrease the density
of serotonin receptors and damage noradrenaline
receptors.
 However, people develop depression
without being stressed and people who
have experienced terrible stress do not
always develop depression.
Does poverty cause
depression?

 Fernald and Gunnar (2008)
 Surveyed 639 Mexican mothers and their children.
Children of depressed mothers living in extreme
poverty produced less cortisol.
 This indicates a “worn out” stress system that leaves
children susceptible to depression.
Cognition and
Depression

 Ellis (1962)
 Proposed that irrational thinking causes depression,
not the other way around.

 Beck (1976)
 Observed that depressed patients’s thoughts are
characterized by:
 Overgeneralization based on negative events
 Non-logical inference about oneself
 Dichotomous thinking (black and white thinking)
Beck’s theory of
Cognitive Restructuring

 Identifies negative, self-critical thoughts
 Notes the connection between negative thought and
depression.
 Examines each negative thought and decides
whether it can be supported.
 Replaces distorted negative thought with realistic
interpretations of each situation.

Buehler & O’Brien
(2011)

 1364 mothers across the US were studied and one
child in the family were studied.
 Interviews and observations were made during the
child’s 1st, 3rd, and 5th grade years.
Findings

 Full-time and part-time mothers reported fewer
symptoms of depression than stay-at-moms.
 Part-time moms were just as involved in their child’s
schooling as stay-at-home moms and were actually
more sensitive with their pre-school children than
stay-at-home moms.
Diathesis-stress Model

 Depression is a result of genetic predisposition and
severe life events such as:
 Unemployment
 Having more than 3 children under 14 at home
 Absence of social support
 Loss of mother at a young age
 Having suffered child abuse
Brown and Harris 1978

 Studied 458 women in London aged between 18 and
65 years.
 Researchers used surveys and interviews on the
women’s life and depressive episodes.
Findings

 In the previous year, 8% of the women had been
depressed.
 90% those who became depressed had recently
experienced a severe life event.
 Only 20% of women who had experienced severe
difficulties became seriously depressed.
 23% of working class women had been depressed
within the past year compared to 3% of middle class
women.