Studies of the offspring of nonschizophrenic co-twins from discordant twin pairs suggest that
A) genetic factors cause schizophrenia, while environmental factors are essentially unimportant.
B) the heritability of schizophrenia involves the transmission of a single dominant gene.
C) a genetic predisposition to schizophrenia may remain unexpressed in some individuals unless it is
released by some unknown environmental factors.
D) environmental factors play a more important role than genetic factors in the origin of schizophrenia.
Question 2
Harold and Tanya both have a wide range of schizophrenic symptoms that came on rather suddenly.
Harold's symptoms have lasted for eight months; Tanya's have lasted only eight weeks. According to the
DSM-IV their diagnoses should be
A) schizophreniform disorder for Harold; brief psychotic disorder for Tanya.
B) undifferentiated schizophrenia for Harold; schizophreniform disorder for Tanya.
C) schizoaffective disorder for Harold; schizophreniform disorder for Tanya.
D) disorganized schizophrenia for Harold; undifferentiated schizophrenia for Tanya.
Twins
Cortical Gray Matter in Monozygotic Twins Discordant for Schizophrenia
The 31 pairs of spinal nerves.
Pregnancy with twins الحمل بتؤام
A pedigree for a Y-linked trait. These traits are transmitted from males to all male offspring in ea
Selected Broad Sense Heritability (H2) Values from Human Twin Studies