Final answer:
A case-control study design can be used to evaluate the claims of family history being associated with narcolepsy. The target population for this study would include individuals with narcolepsy and individuals without narcolepsy, who would serve as controls.
Step-by-step explanation:
The study design that can be used to evaluate the claims of family history being associated with narcolepsy is a case-control study. In this study design, individuals with narcolepsy (cases) will be compared to individuals without narcolepsy (controls) to determine if there is a higher prevalence of family history of narcolepsy in cases compared to controls. This study design allows for the investigation of the association between family history and narcolepsy.
The target population for this study would be individuals with narcolepsy and individuals without narcolepsy, who would serve as controls. The study population can be selected from a clinical setting where individuals with narcolepsy seek treatment or support, and controls can be recruited from the general population.