Kinship study

#bio

Definition

Kinship studies - also known as family or pedigree studies - were a first step in determining whether a behavior or psychological disorder "runs in families."

Features

Kinship studies have several basic characteristics:

• They measure the frequency of a behavior across generations.
• They measure the frequency of a behavior within a generation.
• They are often longitudinal.
• They use case-control studies. Case-control studies are retrospective. They clearly define two groups at the start: one with the behavior/disorder and one without the behavior/disorder. They look back to assess whether there is a statistically significant difference in the rates of exposure to a defined risk factor between the groups - in this case, to potential genetic inheritance.

Evaluating kinship studies

• Kinship studies limit the overall genetic variability of the sample which increases the statistical power of any ge discovery.
• Kinship studies are more controlled than studies of unrelated people. They have all lived in the same home, shared a common diet, and often have the same level of physical activity.
• It is often difficult to obtain reliable data that goes back more than one generation. Kinship studies are often reliant on anecdotal data with regard to the behaviour of grandparents or great-grandparents. This data may be open to memory distortion.  More importantly, it is only recently that a diagnosis of psychological disorders is obtained.  In many cases of past generations, there are assumptions made about potential diagnoses - but no clinical data that can be used.