Abnormal

Question 1

Prevalence rate

Answer 1

KESSLER & BROMET
A - compare prevalence of depression across cultures
T - review of publications containing epidemiological surveys
R - MDD commonly occuring. lifetime prevalence 1% in Czech Republic & 16.9% in USA. 12-month prevalence ranged from 0.3% (CR) to 10% (USA). age of onset does not vary significantly in high income & low income families (25.7 & 25 years old).
C - prevalence rates vary considerably across cultures. may include factors such as classification system, reporting bias & cultural variations

Question 2

Biological etiology

Answer 2

SILBERG ET AL
A - investigate cause of difference in heritabillity of depression in males & females. investigate development of depressive symptoms amond boys & girls from childhood to adolescence
S - 1400 male & female juvenile twin pairs between 8 & 16 years of age
T - longitudnal twin study. data taken from virginia twin study of adolescent behavioural development.
P - Depressive symtoms assessed using child & adolescent psychiatric interview. administered to both twins & at least one parent. list of 39 potentially stressful past-year life events were rated in interviews with mothers
R - life events associated with depression similar in genders. both have similar level of depression before age 12, girl rates of depression increase significantly faster at that age. Analysis showed thats stressful events had greater impact on depressive symptoms of girls than boys, especially during & after puberty
C - negative life events on depressive symptom is stronger in adolescent girls. genetic predisposition to experience particular stressful events.

Question 3

Cognitive etiology

Answer 3

ALLOY, ABRAMSON & FRANCIS
A - investigate whether a particular cognitive style in freshmen is associated with subsequent development of depressive symptoms
S - non-depressed college freshmen
T - quasi experiment
P - participants given questionnaire that determined cognitive style & split into 2 groups based on results: low risk & high risk for depression. Participants were followed longitudnally for 5.5 years.
R - during first 2.5 years of follow up, high risk freshmen more likely to develop MDD than low-risk freshmen (17% vs 1%). higher risk freshmen were more likely than low risk to develop suicidal thoughts & behaviour (28% vs 13%)
C - negative cogntive styles may influence development of MDD.

Question 4

Sociocultural etiology

Answer 4

ROSEQUIST, FOWLER & CHRISTAKIS
A - investigate if depressive symptoms can spread from person to person
T - statistical analysis of social networks, longitudnal data
P - data taken from an earlier framingham heart study of risk factors for heart disease - involving 12,067 participants. to keep track of participants, researchers collected details like names of friends, neighbours, co-workers and relatives. questionnaire for measuring depresison was administered 3 times to one of the cohorts in this longitudnal study. the data was computerized, with a focus on the levels of depression in each inidividual as friends, relatives etc. data analysed using statistical methods.
R - significant correlation in depressive symptoms b/w people up to 3 degrees of separation away. participants were 93% more likely to be depressed if a person they directly connected to was depressed. 43% more likely in two degrees of separation. 37% more likely in three degrees of separation. changes in social ties predicted changes in depressive symptoms.
C - depression in one person may cause it in people that individual is socially connected to. symptoms of depression may spread along the network of social connections like an infectious disease.