Who participates in a family study?

Area of Science:

• Psychiatry
• Genetics
• Clinical Psychology

Background:

• Family studies are crucial for understanding the genetic and environmental influences on psychiatric disorders.
• Participation bias can significantly impact the generalizability of findings in these studies.
• Previous research has not fully elucidated the specific sources of bias in family studies of mood and personality disorders.

Purpose of the Study:

• To investigate potential subject participation biases in a family study of mood and personality disorders (PDs).
• To examine biases at three distinct levels: proband consent, relative access, and relative participation.
• To identify the primary source of sampling bias in family genetic studies.

Main Methods:

• The study included 156 outpatients with mood and PDs and 611 first-degree relatives.
• Axis I and II disorders were assessed using structured diagnostic interviews.
• Family history interviews provided informant reports on relatives.

Main Results:

• Probands granting or withholding consent did not significantly differ on most variables.
• Relatives denied access by probands were significantly more likely to have drug abuse and PDs.
• Few differences were observed between participating and non-participating relatives.

Conclusions:

• The greatest risk of sampling bias in family studies arises from probands withholding access to relatives with substance abuse and PDs.
• Understanding these biases is critical for accurate interpretation of genetic and etiological research findings.
• Strategies to mitigate this specific bias should be considered in future family study designs.