Stability of symptoms of psychological distress: A 13-year study using Australian national data

This study examined the stability of 10 symptoms of psychological distress measured by the Kessler Psychological Distress Scale (K10) in an Australian adult sample. Data were collected at seven time points, 2 years apart, between 2007 and 2019. The average stability of the 10 symptoms was 49%. However, there were differences between items. The items can be categorised based on two characteristics: Degree of extremity and arousal. More extreme symptoms (i.e., those beginning with 'so', such as 'so sad that...') tended to change more over time, whereas milder symptoms (e.g., "nervous") tended to be more stable. Symptoms with low levels of arousal (e.g., 'hopeless') tended to reflect more situation-specific influences, whereas symptoms with high levels of arousal (e.g., 'restless or fidgety') tended to reflect more nonsystematic influences.