Genetics and Family Risk

Question 1

What is the heritability of Depression?

Answer 1

33% (same as cancer)

Question 2

What is the heritability of Bipolar Disorder?

Answer 2

80%

10-fold increased risk among relatives of ppl with BD I or II, compared to gen pop

Question 3

What is the heritability of Schizophrenia?

Answer 3

50-80%

Question 4

What is the heritability of OCD?

Answer 4

50%

First-degree relatives 2x as likely to have OCD than gen pop; 10x as likely if childhood onset of OCD

Concordance rates in monozygotic twins >0.5 (up to 87%), dizygotic twins 0.2-0.5

Question 5

What is the risk of developing schizophrenia for a monozygotic twin of a pt with scz?

Answer 5

40-50%

Question 6

What is the risk of developing schizophrenia if both of your parents have schizophrenia?

Answer 6

40%

Question 7

What is the risk of developing schizophrenia if 1 of your parents has schizophrenia?

Answer 7

12% (10-16%)

same risk for a dizygotic twin

Question 8

What is the risk of developing schizophrenia if your non-twin sibling has scz?

Answer 8

8%

3-5% for a second-degree relative, eg. grandparent or aunt/uncle

Question 9

What is the risk of developing Bipolar d/o for a monozygotic twin of a pt with bipolar d/o?

Answer 9

45-70% (a bit higher than for schizophrenia)

5-10% for first-degree relatives

Question 10

What is the heritability of ADHD

Answer 10

0. 76-0.8

* *Hyperactivity is more heritable than inattention

Question 11

If a parent has ADHD, what is the chance their child will have ADHD?

Answer 11

50%

Question 12

If a child has ADHD, what is the chance their parent had ADHD?

Answer 12

25%