A memory cue followed by listening to a podcast (on own smartphone) for ca. 12 minutes.

Self-report measure that assesses subjective distress after a traumatic event (with reference to the trauma film). Here we include the intrusion subscale (8 items). Items are rated on a 5-point scale ranging from 0 ("not at all") to 4 ("extremely"). Items are summed (subscale score ranges from 0 to 32). Higher scores indicate worse outcome.

A single bespoke item on impact on daily functioning associated with the intrusions from the trauma film rated on a 11- point scale (from 0 "none"; 5 "some"; 10 "extreme"). Higher scores indicate higher level of functional impairment.

A single bespoke item measuring the level of concentration disruption associated with the intrusions from the trauma film (11 point scale from 0 to 10). High scores indicate higher level of concentration disruption.

Two self rated items: Item 1 measures the extent of being troubled by poor sleep (with reference to study event) on a 5-point scale (from not at all to very much), and item 2 measures the number of nights in the week with sleep problems on a 5-point scale (from 0-1 to 5-7 nights). Each 5-point scale is reverse scored (4 - 0) then summed. Possible total scores range from 0 - 8, with higher values indicative of better sleep.

Self-report measure assessing preventative behaviors during the covid-19 pandemic (adapted for Swedish student population). 12 items are rated on a 5-point scale ranging from 1 ("Extremely unlikely") to 5 ("Extremely likely"). Items are summed. 4 items are reverse scored. Higher sum scores indicate more preventative behaviors during the COVID-19 pandemic.

In the Intrusion Provocation Task (IPT), participants are presented with neutral still images from the trauma film. Immediately afterwards for the next two minutes, they are allowed to think freely and report intrusions by pressing a button. The IPT intrusion score is calculated by the total frequency of intrusions (i.e. number of button presses), whilst higher values represent more intrusions.

The verbal recognition memory test comprises a number of true/false written statements relating to the trauma film. Participants indicate true or false as to whether or not the written statement about the film they watched 7 days earlier is correct. The score is the sum of correct responses, a higher score indicating better verbal recognition memory of the trauma film.

The visual recognition memory test consists of static visual images - some are taken from throughout the film (different images from those used in the IPT), and some are unviewed images presented as filler. Images are presented individually and participants are instructed to view each image for 5 s. Participants indicate yes or no as to whether or not they recognize the image as being from the trauma film they watched 7 days earlier. The score is the sum of correct responses, a higher score indicating better visual recognition memory of the trauma film.

8 self-report items (5-point scale from 1 to 5) measuring time perspective on three subscales: past perspective (items 3, 5, 7), present perspective (items 1, 8) and future perspective (items 2, 4, 6). Item scores for each subscale will be summed. Higher values indicate higher levels of past/present/future time perspective.

Three free text response fields asking to imagine a future self identity in relation to social/occupational/other important situations. A single item measuring which of these future identities has been most affected by the COVID-19 pandemic. Then a free text response field to describe a mental image of this identity, 4 items measuring vividness

(1 "not vivid at all", 10 "very vivid"), positivity (1 "very negative", 10 "very positive"), regularity of rehearsal (1 "never", 10 "very regularly"), and likelihood (1 "not at all likely", 10 "very likely") of that image on a 10-point scale. 3 items measuring the perspective of viewing that mental image ("through own eyes" or "as if seeing oneself"), whether other people are in the image (if yes, how many), and how old one will be in the image. All items are answered in terms of how the image was before and after the COVID-19 pandemic. Free text response field asking how the COVID-19 pandemic affected the future identity image.

Self-report measure that assesses expectancies about positive future life events. 10 items are rated regarding how likely it is that the event will happen in one's future on a 7-point scale ranging from 1 ("not at all likely") to 7 ("extremely likely"). Items are summed. Higher scores indicate more optimistic/positive future expectancies.

6 visual analogue scale ratings measuring how sad, hopeless, depressed, fearful, horrified and anxious participants feel "right at this very moment" on a scale from 1 "not at all" to 10 "extremely" assessed before and after film viewing and after completing the experimental or control condition task as well as in the beginning of session 2 (Week 1 follow- up). Rating are summed yielding a composite negative mood score, with higher scores indicating higher negative mood.

4 rating scales measuring how distressing participants found the trauma film, how much attention they paid to the film, how personally relevant the film was for them and how much they looked away from the film on a 11-point scale from 0 "not at all" to 10 "extremely".

6 free text response fields in which participants are asked to list the images/moments of the trauma film that were worst for them with a brief description. This list is part of the memory cue procedure in the experimental/control condition. For each hotspot, 2 self-rated items measuring the level of distress and vividness associated with the hotspot (11-point scales from 0 to 10). High scores indicate higher level of distress/vividness.

4 rating scales measuring how entertaining/difficult/distracting participants found the task they were doing in the experimental/control condition and how much attention they paid to the task they were doing in the experimental/ control condition on a 11-point scale from 0 "not at all" to 10 "extremely".

2 items measuring to which extent participants believe that playing Tetris/listening to a podcast after watching a distressing film increases or decreases intrusive memories of the film on a 21-point scale from -10 (extreme decrease), 0 (no effect), to 10 (extreme increase).

4 items measuring to which extent participants agree to statements about being aware of the purpose of the study on a 7-point scale from 1 "Do not agree at all" to 7 "Completely agree". Two items are reverse scored and then all items are summed. Higher scores indicate higher demand effects.

5 items measuring the number of hours (0-11 or more) per day during the previous week that participants consumed COVID-19 related media content on TV, radio, newspaper, online news, or social media.