Final answer:
The severity of mental disorders tends to have a positive correlation with the number of comorbid disorders, which aligns with the dimensional approach to diagnosis; therefore, the answer is 'positively; consistent'.
Step-by-step explanation:
The question addresses the relationship between the severity of a mental disorder and the presence of comorbid mental disorders. When individuals are diagnosed with multiple mental disorders, studies have found that there is often a positive correlation between the severity of one disorder and the number of additional disorders present. This means that as someone has more comorbid disorders, the intensity of each disorder is likely to be greater.
This finding is consistent with a dimensional approach to diagnosing mental disorders, which suggests that psychological issues can have varying degrees of severity and are not merely present or absent. Hence, the correct answer to the student's question would be 'b. Positively; consistent' as this best aligns with the available research and understanding of comorbidity in mental health.