(1) Epidemiology - season of birth, flu, pop. density, vit D deficiency

Question 1

Season of birth

Answer 1

1. sch. more likely in people born in late winter or early spring
2. February thru May in northern hemis
3. replicated in different countries
4. some studies show same pattern in southern hemis  August thru December
5. women may be more likely to contact virus in winter flu season during 2nd trimester, a critical period of neonatal neurological development
6. schizo births highest after coldest falls when people would have been indoors more

Question 2

Sch. increased after flu epidemics

Answer 2

1. peak increase in sch. births occurred 5 mos. after epidemic started suggesting women in the 2nd trimester of pregnancy were at increased risk
2. blood serum of pregnant mothers whose children later developed schizo had proteins produced by the immune system suggesting they possibly had viral infections

Question 3

Population density

Answer 3

1. Seasonality effect primarily in urban areas
2. Risk of develop schizo 3 X’s higher in urban compared to rural dwellers
3. May be because of increased risk of viral exposure in densely populated areas
4. But also, up to age 15, risk of schizo increases with longer time living in urban areas – indicating environmental influence of urban living

Question 4

Vitamin D Deficiency

Answer 4

1. Vit D plays important role in brain development
2. Relationship in maternal vit D deficiency and schizo in children:
   - in more northern latitudes where there is less sun exposure
   - urban areas – where lifestyle may result in less sun exposure
   - People with darker skin, especially when they live in northern latitudes
   a. Darker skin and reduced sun exposure both reduce vit D synthesis
3. Vit D supplement in first year of child’s life associated with reduced risk of schizo in boys

Question 5

Nutritional deficiency

Answer 5

1. Hunger winter - 2 X increase in sch. 5 mos. after end of famine in Netherlands when WW II and Nazi blockade ended
2. may have been due to toxic effects of thiamine deficiency and increased food intake after famine was over
3. increased incidence of schizo when mother was underweight during pregnancy and when baby is born low birth weight

Question 6

Possible protective factors for people with GENETIC RISK

Answer 6

1. Avoid exposure to:
   - Toxins
   - Infectious vectors
   - Early life stressors
   - Early life cannabis use
2. Good nutrition
3. Vit B & D supplementation
4. Supportive family and social

Question 7

Perinatal factors

Answer 7

1. Substance use of mother
   - Maternal and paternal smoking associated with increased risk of schizo
   - Excessive etoh intake by mother associated with increased schizo risk – i.e. > 7 ozs. “pure alcohol” per week
2. Birth trauma and pregnancy complications
   - pregnancy complications more likely if schio person does not have family hx of schizo
   - Complications of pregnancy
   a. gestational diabetes
   b. Rh incompatibility
   i. Rh is a protein clotting factor in blood
   ii. if mother is – and baby is positive, mother will develop antibodies Rh antibodies that will not affect the 1st child but will cause anemia in subsequent children
   iii. increased incidence of sch. in 2nd and later Rh+ children born to Rh- mothers
   c. bleeding
   d. preeclampsia - mother has HTN, edema,
3. abnormal fetal development
4. complications of labor and delivery
   - emergency Caesarean
   a. fetal hypoxia - interruption of blood flow / oxygen