Participants in this arm will be asked to decide alongside with the intervention provider (a clinical PhD student or M.A student under the supervision of the principal investigator) to imagine a script based on a future distressing anxiety provoking scenario multiple times while honing in on the most negative aspects.

Participants in this arm will be asked to decide alongside with the intervention provider (a clinical PhD student or M.A student under the supervision of the principal investigator) to imagine a script based on a past distressing anxiety provoking scenarios one time while honing in on the most negative aspects. Afterwards they will insert changes into the script that try to help them cope in the imagery: First imagining the scenario from a different character perspective that enacts changes in the memories. Second, The will imagine the scenario again from the original perspective along with changes done by the additional character.

Participants in this arm will be asked to decide alongside with the intervention provider (a clinical PhD student or M.A student under the supervision of the principal investigator) to imagine a script based on a future distressing anxiety provoking scenarios one time while honing in on the most negative aspects. Afterwards they will insert changes into the script that try to help them cope in the imagery: First imagining the scenario from a different character perspective that enacts changes in the memories. Second, The will imagine the scenario again from the original perspective along with changes done by the additional character.

The OASIS is a 5-item validated self-report instrument assessing sum of anxiety related symptoms, distress avoidance and functioning symptom intensity over the past week (Taylor et al., 2007). Possible scores range from 0 to 4.

Sum scores range is 0-20.

Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The TAFS-R is a validated 19 item self-reported instrument assessing belief in statement that describe the irrational assumption that just because a "bad" thought presents itself to the mind, then it is undeniably followed or accompanied by a specific "bad" action. Possible scores range from 0 (Do not agree) to 4 (Agree alot).

Sum score (0- 76) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The Waterloo Image and Memories Interview (WIMI) is a validated structured interview for assessing content of imagery and memories. valence of the details will be scored using a trained coder.

change = post-intervention - Baseline Score. The participant provides descriptions of a negative imagery and memory related to his primary symptoms dimension.

The Waterloo Image and Memories Interview (WIMI) is a validated structured interview for assessing content of core beliefs related to the future imagery and memory.

Believability will be given by the participant for each identified core-belief on a scale of 0 (Do not believe it at all) to 100 (Completely Believe it).

change = post-intervention - Baseline Score.

The iBAT is currently being developed in our lab. The more levels the participants pass (listen to imaginal scenario in full without pressing "skip") the higher the score he receive (from 0 to 10)

There are two versions in the task, each with different 10 scenarios. The versions will be counterbalanced across participants.

Recruitment is completed for the first sample and pre-registration is available at the open science framework website:

change = post-intervention - Baseline Score.

https://osf.io/bp42h/?view\_only=5211617cedf94f71a4daa746e98d924a

the BCSS measures participants' self-beliefs about themselves and others. It is a well validated self-report instrument. It has 24 items total. Each item is scored from 1 (believe it slightly) to 3 (believe it totally)

Two sum scores: self (0- 36), other (0-36) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The SCS is a validated self-report measure, that measures participants' tendency to react to one own suffering and misfortune with self-compassion. It has 12 items with scores ranging from 1 (Almost never) to 5 (Almost always).

Sum score (12- 60) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The IFES is a validated self-report measure, that measures participants' symptoms in reaction to negative future events. It has 24 items with scores ranging from 0 (Not at all) to 4 (A lot).

Sum score (0- 96) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The IES is a validated self-report measure, that measures participants' symptoms in reaction to negative past events. It has 22 items with scores ranging from 0 (Not at all) to 4 (A lot).

Sum score (0- 88) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The DTS is a validated self-report measure, that measures participants' ability to tolerate distress. It has 15 items with scores ranging from 1 (Completely agree) to 5 (Completely do not agree).

Sum score (15- 75) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The ECR-S is a validated self-report measure, that measures participants' behavior in close relationships and maps these behaviors on dimensions of anxious attachment and avoidant attachment. It has 12 items with scores ranging from 1 (Strongly Disagree) to 7 (Strongly Agree).

Two average scores: anxious attachment (1-7), other (1-7) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The MCQ-30 is a validated self-report measure, that measures participants' beliefs about their cognitions. It has 30 items with scores ranging from 1 (Do not agree) to 4 (Agree a lot).

Sum score (30- 120) Change = 1: (post-intervention score - Baseline Score) 2: (Follow-up score - Baseline Score)

The BCIS is a validated self-report measure, that measures participants' cognitive insight about their symptoms. It has 15 items with scores ranging from 0 (Do not agree) to 3 (Completely Agree).

Sum score (0- 45) Change = 1: (post-intervention score - Baseline Score)

The Locus of control scale measures participants feeling of control over their problems in life. It has 5 items with scores ranging from 1 (Completely not agree) to 5 (Completely Agree).

Sum score (5- 25) Change = 1: (post-intervention score - Baseline Score)

The SAIQ assess attitudes toward mental illness among persons receiving psychiatric treatment.

There will be 8 items from that questionnaire:

0 (Not at all) to 3 (A great deal) In general, how much do you tend to worry? How much do you worry about your condition? How much do you worry about losing friends because of your condition? How much do you worry about being unable to work because of your condition?

0 (Strongly agree) to 3 (Strongly Disagree) Do you believe the current treatment to be necessary? I think my condition requires psychiatric treatment I think my condition will go away by itself? If I were to discontinue treatment today I would do fine

Change = 1: (post-intervention score - before intervention) 2: (after intervention - before intervention)

In this task, participant will classify sentences into two categories (TRUE of FALSE). Sentences are statement taken from the brief core schema scale describing self-beliefs in a positive or negative way. Participants in one block would have to respond TRUE to the positive statements and FALSE to the negative statements. In the second block, the instruction will be reversed, and participants will respond TRUE to the negative statements and FALSE to the positive statements.

For each participant a d score will be calculated based on the algorithm in Greenwald, Nosek and Banaji (2003) paper.

change = post-intervention - Baseline Score.

The task requires participants to perform serial additions using the two previously displayed single digits (1-9) in a long running series of digits. They need to add the digits by pressing numbers presented on a circle on screen (2-18). The latency between digits begins at 3s in the initial 3 min block allowing participants to acclimatize to the task itself. The second block is 5-min long with a shorter display latency of 2 s between digits. The third block has a latency of 1s and can last for a maximum of 10 min; however, participants are instructed during the rest period that due to the difficulty they are allowed to end this block at any time by pressing a designated key on the terminals' keyboard. Duration of the third block provides a time measure for resistance to psychological stress

change = post-intervention - Baseline Score.

The first 3 OASIS (see above) items pertaining to frequency, severity and avoidance of anxiety.

Two of the following symptom focus area (based on the results from the DIAMOND interview in the baseline assessment):

social anxiety (1-7): I was afraid I will say or do the wrong things. I was afraid what other people would think of me. I was afraid others would not accept me. Obsessions and compulsions: three items from the OCI-R that participant scored the highest at. (0-4) Anxiety sensitivity: (0-4) I was anxious that a panic attack would occur. I was anxious I would not be able to handle the panic attack. I was anxious something horrible would happen if a panic attack would occur. I tried to avoid experiencing a panic attack. Generalized anxiety: (0-4) I couldn't worrying or controlling my worry. I was so restless I had trouble sitting down without moving. I was way too worried about different things.

Participants will fill out 9 items pertaining to specific symptoms and mechanisms (Not at all 0 to 100 Very much VAS):

I believed that if I thought or imagined an unpleasant event it causes it more likely to happen.

I believed that if I thought or imagined I would behave in a negative way it is more likely that I would actually behave this way I believed my thoughts become reality, if I think something it will come true I felt vulnerable I felt weak I tried being understanding and patient towards the aspects in my personality I do not love I try to remind myself that feelings of inadequacy are shared by most people I couldn't handle feelings of stress or distress I did everything to stop feeling stress or distress.