Adrenaline

• Stage fright is physiologically caused by the release of adrenaline into the blood stream. This is known as the "fight or flight" chemical, the Stage Fright Help website notes, and it is triggered by fear or panic.
  
  

Circumstances

• Some anxiety is normal before a performance, but stressful circumstances can intensify stage fright. This might happen if a performer is under stress because she is running late or an important critic is in the audience.
  
  

Lack of Confidence

• Performers may be more susceptible to stage fright if they lack self-confidence, worry about other people's perception of them or are trying too hard to be perfect, Stage Fright Help explains. Self-reflection may help someone to understand and address these problems.