Question

Rana and Sara are identical twins. When Rana was eight she watched her uncle die of a heart attack. She was alone with his body for 20 minutes before help arrived. After that Sara was sent to live with relatives, and did not come back until the twins were 12. Rana is 17 now and has developed schizophrenia. Sara shows no signs of the disorder. What is the best explanation for this?

a. Rana and Sara likely both have a genetic predisposition for the disorder, but symptoms presented in Rana because she experienced a traumatic event early in life.
b. Rana and Sara likely both have a genetic predisposition for the disorder, but Rana probably developed the disorder because she was taken away from her sister when she needed her most.
c. Due to Rana's traumatic experience of watching her uncle die, she developed schizophrenia. Traumatic experiences like that at a young age can cause the disease.
d. Rana was genetically inclined to develop the disorder, and most likely would have developed it in her early twenties. The experience with her uncle only caused it to come about sooner.

Answer 1

The best explanation for Rana developing schizophrenia and not Sara is that both twins have a genetic predisposition, but Rana's exposure to a traumatic event contributed to the presentation of symptoms. This finding supports the notion that the interaction of genetic risk and environmental stressors is necessary for schizophrenia to develop.

Step-by-step explanation:

The best explanation for why Rana developed schizophrenia while her twin sister Sara did not is a. Rana and Sara likely both have a genetic predisposition for the disorder, but symptoms presented in Rana because she experienced a traumatic event early in life. The study by Tienari et al. shows that genetic vulnerability combined with a disturbed family environment significantly increases the risk of developing schizophrenia or related psychotic disorders.

This aligns with the broader understanding that while genetics may provide a predisposition, environmental factors, such as traumatic events, play a crucial role in the manifestation of schizophrenia. Rana's traumatic experience of being alone with her deceased uncle could have served as a significant environmental stressor, possibly triggering the onset of her schizophrenia symptoms.

While Sara did not witness the traumatic event and likely grew up in a less disturbed environment during her formative years, this may have protected her from developing the disorder, despite potentially sharing a similar genetic risk with Rana. Both nature and nurture interact in complex ways to influence the development of psychiatric disorders, as evidenced by differential outcomes in identical twins like Rana and Sara.