diathesis stress model in explaining SZ

what does the diathesis stress model suggest?

SZ is caused by a combination of biological and environmental traits

how can SZ be explained by biological factors

the closer your genetic connection to someone with SZ, the greater your risk of developing the disorder e.g., MZ twin =48%; 1st degree relative = 6-17%

why can’t SZ be entirely determined by biological factors

MZ twins would have a 100% concordance rate

Gottesman & Bertelson

even when one MZ twin did not have symptoms of schizophrenia but the other did, if both twins had children the children had statistically the same likelihood of developing schizophrenia

* suggests strong genetic implications

Rosenthal

* reported on quadruplets who all developed SZ


* developed at different ages and different forms of the condition
* they all inherited a predisposition to the disorder but all had different environmental experiences within the family
* implies environmental factors affect the onset of SZ

Hong et al

* focused on identifying the specific gene responsible for SZ
* ound that a variation in the TPH gene (involved in the production of an enzyme) was significantly more common in Chinese patients with schizophrenia than Chinese controls