Lecture 1: Epidemiology

Question 1

What is the definition of Epidemiology?

Answer 1

The study of the number and patterns of occurrence of a disease, as well as possible causes and risk factors

Question 2

What is the definition of Prevalence?

Answer 2

How many people have the disorder now

Question 3

What the definition of incidence?

Answer 3

How many new case sin a specific period of time

Question 4

What is the definition of life-time prevalence?

Answer 4

How common for any individual across life

Question 5

What is the prevalence of SZ?

Answer 5

1.5-4.0%

Question 6

What is the incidence of SZ?

Answer 6

It is difficult to estimate because the first presentation of a psychotic episode may not be SZ.

Question 7

What is the life-time prevalence of SZ?

Answer 7

0.7/100 or < 1 %

Question 8

What is the age of onset?

Answer 8

Late adolescence

Question 9

What is the recovery rate?

Answer 9

Low: 10-15%

Question 10

What is the prevalence of SZ worldwide?

Answer 10

1.5-4.0%

Question 11

What were 3 statistics in 1999/2000 for SZ in Canada?

Answer 11

1) 300,000 Canadians hospitalized
2) $6.9 billion in health-care costs
3) 1 in 12 hospital beds (similar to heart disease and stroke)

Question 12

What was the main finding of the 1999/200 study on SZ?

Answer 12

A strong association with homelessness and substance abuse; some association with violence

Question 13

Prevalence and incidence can be affected by two things. What are those two things?

Answer 13

1) Culture

2) Migration

Question 14

Why would culture influence prevalence and incidence of SZ? (hint: culture is different than migration)

Answer 14

Cultures may view symptoms of SZ differently, resulting in different rates of people seeking treatment and diagnosis.

Question 15

Why would migration influence prevalence and incidence of SZ?

Answer 15

1) Immigrants have a 2.5x higher rate of psychotic disorders
2) May be related to stress, health risks in either home country before migration or in new country
3) Many migrants leaving or arriving in the context of war or natural disaster

Question 16

Prevalence and incidence can also be affected by parental age. Provide an explanation as to why that is.

Answer 16

Children of very AMABS.
Increasing risk over age 25
Male sperm (germ line cells) are a common source of genetic mutations
As AMABS (and their sperm) age, mutations are more common

Pre-natal or birth complications
<20 and >35
Complications more common in younger and AFABs

Question 17

Prevalence and incidence may also be affected by exposure to inflammation and infection pre-natal or in infancy. How so?

Answer 17

1) Children born during flu epidemics at higher risk

2) Children of AFABS known to have had a viral infection > risk

Question 18

Latitude and season of birth is also a risk factor. How so?

Answer 18

• Some evidence that distance from the equator is related to greater risk
• People born in colder months at greater risk.
• May be related to greater risk of infections

Question 19

Name 3 factors that can also affect prevalence and incidence (risk factors).
(hint: SUC)

Answer 19

1) SES
2) Urban environment
3) Childhood trauma

Question 20

How can SES affect prevalence and incidence?

Answer 20

Poverty associated with increased risk

Question 21

How can urban environment affect prevalence and incidence?

Answer 21

• In many countries, concentration of poverty in urban areas

- Social stressors

Question 22

How can childhood trauma affect prevalence and incidence of SZ?

Answer 22

1) Childhood trauma = 2-4x increase in risk

2) People with SZ have greater incidence of serious trauma

Question 23

What are the negative outcomes of SZ?

Answer 23

1) Frequent health problems:
2) Cardiovascular disease, stroke
obesity, diabetes
3) Substance disorders
4) Suicide
5) Violence and victimization
6) People with SZ more likely to die at a younger age