Adjustment disorder, PTSD, and their predictors throughout the COVID-19 pandemic: results from the longitudinal ESTSS ADJUST study in Poland

disorders are associated with serious consequences that can lead to poor quality of life and increased use of healthcare and other social services (Atwoli et al., 2015).Diagnosis of AjD, a disorder specifically associated with stress, requires that there is one or more identifiable psychosocial stressor, symptoms that are indicative of preoccupation with the stressor or its consequences, failure to adapt to the stressor, and that the symptoms emerge within one month of the stressor, causing significant functional impairment (WHO, 2019).When the event is traumatic (i.e., involving a threat to life or serious injury), it may lead to PTSD, a disorder that is characterised by symptoms such as reexperiencing the event, avoidance of related stimuli, heightened arousal, and marked changes in mood and cognition (American Psychiatric Association, 2013).Epidemiological studies on the prevalence of AjD in the general population before the COVID-19 pandemic were generally rare and showed quite high variation in prevalence rates, between 1.4% in Germany and 17.5% in Israel (Ben-Ezra et al., 2018;Perkonigg et al., 2018;Shevlin et al., 2019).This is not the case with PTSD, for which research has been conducted in many countries around the world for many years.In Europe, estimates for current PTSD diagnosis ranged from 0.4 to 0.5% (in Spain and Germany, respectively) to 6.67% in Croatia (Alonso et al., 2004;Burri & Maercker, 2014;Wittchen et al., 2011).Researchers also identified PTSD risk factors operating before, during, and after the trauma, such as gender (female), adverse childhood experiences, psychiatric history, trauma severity, lack of social support, or additional life stress (Brewin, Andrews, & Valentine, 2000).In general, these factors are non-specific, for example female gender is a well-known risk factor for emotional disorders, and childhood trauma is a transdiagnostic risk factor mental health disorders (Hogg et al., 2023).In the case of AjD, little research before the pandemic was conducted on risk or protective factors for this disorder; among identified demographic risk factors were