I am Jeanie Tse, and I'm here to speak with you about the question, "What are a baby's chances of inheriting schizophrenia?"
The general population risk of schizophrenia is about 1 percent. So, one in 100 babies is going to develop schizophrenia. But, if you have first degree relative with schizophrenia, so your mother, father, brother, or sister, then your risk goes up to 10 percent. So, it's ten times more. But, it's still a small percent chance that it will occur.
If you have an identical twin who has schizophrenia, so you share all the same genes, then your risk is 50 percent. So, it's not 100%. There are environmental factors that determine whether you will have it or not, even though you have the same genes as your twin. But, if you have a non-identical twin, it's the same as having a sibling, so it's back to 10 percent.
If you have one parent who has schizophrenia, again, the risk is 10 percent, but if both of your parents have schizophrenia, you would think that risk would be very high. It's higher, but it's still only 40 percent. So, four times more likely, if both parents have schizophrenia.
Among relatives of people who have schizophrenia there's a five times increased risk of what we call schizophrenia spectrum disorder. And so that might include sometimes having a paranoid delusion, but not the full blown picture of schizophrenia, or maybe hearing voices once in a while, but again, being able to function then the average person that has schizophrenia.
And so, if you're a baby and you have family members that have schizophrenia, you do have an increased risk, but the risk is still low.