Final answer:
The correct statement about schizophrenia is that Type I schizophrenia is more responsive to drug therapy than Type II schizophrenia, due to the effectiveness of antipsychotic medications in targeting dopamine receptors associated with positive symptoms.
Step-by-step explanation:
The correct statement about schizophrenia is a. Type I schizophrenia is more responsive to drug therapy than Type II schizophrenia. Type I schizophrenia is characterized by positive symptoms which are more responsive to antipsychotic medications that act as dopamine antagonists. These medications are designed to block dopamine receptors and reduce overactive dopamine neurotransmission, which is associated with the positive symptoms of schizophrenia such as hallucinations and delusions. Evidence from various studies including those on dopamine neurotransmission and the effects of antipsychotics support the notion that Type I schizophrenia has a better response to drug therapy compared to Type II, which is often linked to negative symptoms and structural brain abnormalities.
In contrast, statement c. Drugs that treat schizophrenia are antagonistic for norepinephrine is incorrect because schizophrenia is primarily associated with overactivity in the dopamine system, and the drugs designed to treat it mainly target this neurotransmitter, not norepinephrine.
Regarding statement b. There is an increased vulnerability to schizophrenia for those born in the summer/fall month, research has shown mixed results, and while there can be seasonal correlations, it is not a straightforward relationship. Lastly, statement d. The concordance rate for schizophrenia among identical twins is about 50% is not entirely accurate, as concordance rates for schizophrenia in identical twins vary, generally ranging from 40-50%, indicating that both genetic and environmental factors contribute to the disorder.