2.3.1. State-Trait Anxiety Inventory (STAI)

The structure of the STAI tool is based on differentiating between anxiety understood as a transitory and situation-dependent state, and anxiety understood as a relatively constant personality trait. In his concept, Spielberger referred to other, earlier studies conducted by R.B. Cattell and I.H. Scheier [16]. They identified two different factors. The first, responsible for situation-dependent score variability, was called "state anxiety". The other, responsible for inter-individual differences, was termed "trait anxiety". The STAI questionnaire consists of two independent parts, each containing 20 statements. The first part, STAI X-1, can evaluate anxiety considered as the current emotional state. This part of the questionnaire is a very sensitive tool. It enables one to trace the dynamics of anxiety even in short time intervals. The other part, STAI X-2, concerns anxiety understood as a personality trait [17]. The patient responds to each statement by choosing one of 4 options. The level of anxiety is expressed as the score resulting from summing up the sub-scores obtained for all individual responses. The scores from each part of the questionnaire may vary from 20 to 80. The test is interpreted in the following way: the higher the score, the higher the level of perceived anxiety. The score range of 39–40 in state anxiety evaluation suggests the detection of clinical symptoms of anxiety disorder [18,19]. The psychometric value of the test makes it useful in group studies. The test reliability, based on the internal consistency coefficient, varies from 0.76 to 0.92 in adult women and men. The construct validity of the X-1 scale ranges from 0.51 for men to 0.57 for women [17].
