What is the Yale Global Tic Severity Scale (YGTSS)?

The YGTSS is a comprehensive clinical rating scale designed to assess the severity and impairment associated with motor and vocal tics. It is widely used in clinical practice and research for Tourette syndrome and other tic disorders.

Who developed it and when?

Developed by James Leckman and colleagues at Yale University in 1989, specifically for evaluating tic disorders in children and adults.

What type of assessment is it?

Semi-structured clinical interview and rating scale, typically administered by trained clinicians.

What does it assess?

• Motor tic severity (number, frequency, intensity, complexity, interference)
• Vocal tic severity (number, frequency, intensity, complexity, interference)
• Overall impairment in functioning
• Changes over time with treatment

How many items and what format?

11 items: 5 for motor tics, 5 for vocal tics, and 1 overall impairment rating, each rated 0-5.

How is it scored?

Motor and vocal tic scores (0-25 each), total tic score (0-50), and impairment score (0-50). Global severity score combines tic score and impairment (0-100).