In the treatment of obsessive–compulsive disorder (OCD), imagery rescripting (ImRs) is considered promising. However, there is a paucity of randomized-controlled trials (RCTs) with active control groups in this context.
Methods
We developed an audio imagery, which we refer to as the spit-face scenario, to induce disgust without any sexual content. In an online RCT, we then investigated disgust (SDQ-13, visual analogue scale (VAS)) and anxiety (STAI-SKD, VAS) in participants reporting at least mild OC symptoms after one of three manipulations, ImRs (n = 34), imagery focus (n = 25) or distraction (n = 34).
Results
The spit-face scenario significantly induced disgust, e.g., comparable with watching a disgusting film, and over 70% of the participants were able to vividly visualize and follow the scenario effectively. Although ImRs and distraction reduced disgust, it did not decline following imagery focus (e.g., SDQ-13, F-HF = 86.600 (1.756), p < .001, f = 0.98). Whereas disgust performed similarly in the SDQ-13 and the VAS, there were slightly different patterns in the anxiety measures.
Conclusions
Although the results might suggest an effect of a one-session online ImRs audio manipulation, the question remained if ImRs had a differential effect beyond distraction. The results thus underline the need to conduct further research on the active elements of ImRs.
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Introduction
According to major national treatment guidelines, cognitive-behavioral therapy (CBT) is the first-line treatment for obsessive–compulsive disorder (OCD), and it has shown its efficacy in numerous randomized-controlled trials (e.g., APA, 2007; DGPPN, 2022; NICE, 2005). CBT is continuously being developed further, and clinical interventions focusing on imagery rescripting (ImRs) are considered one promising route. Principally, ImRs aims at activating stressful mental images, and at changing them in the imagination in such a way that the resulting image is associated with more positive emotions (Ehring et al., 2022). Developed from different theoretical backgrounds, and integrated, to a greater or lesser extent, within different therapy modalities such as schema therapy or acceptance and commitment therapy, the specific implementation of ImRs may differ (Cooper et al., 2023; Ehring et al., 2022).
ImRs was originally developed for posttraumatic stress disorder (PTSD), but has since been applied to other disorders (Strachan et al., 2020). Concerning PTSD and anxiety disorders in general, and compared with passive control conditions using different study designs (from case series to randomized controlled trials, RCTs), ImRs has been described as efficacious (Morina et al., 2017). However, the evidence base of ImRs still lags behind that of well-established interventions such as prolonged exposure, and thus, intensive research activities are currently being undertaken (Ehring et al., 2022). This has resulted in more RCTs being conducted during the last few years, which have again yielded large effects of ImRs, compared with passive (mostly waitlist) control conditions (Kip et al., 2023). When compared with active controls (such as prolonged/exposure or cognitive restructuring conditions), ImRs was equally effective (Kip et al., 2023).
In line with the above, PTSD patients who had experienced childhood sexual abuse and persistently felt disgusted or contaminated as a result (n = 17), benefited from mental imagery on skin or cell renewal within a CBT protocol, compared with a waitlist group (n = 17), with large effects at one-month follow-up (Jung & Steil, 2013). A feasibility study also showed that this CBT protocol reduced OCD-related feelings of contamination and disgust (Fink-Lamotte et al., 2023). In that sense, targeting mental images is not only therapeutically useful for PTSD. It is also promising in OCD treatment, as intrusive thoughts and images are a key symptom of the disorder (APA, 2022). According to an experimental investigation with n = 30 patients diagnosed with contamination-related OCD and the same number of healthy controls, disgust that was induced visually was reduced almost as efficacious through ImRs as through cognitive reappraisal (Fink et al., 2018) or active imagery controls (Fink-Lamotte et al., 2022), and more than in a distraction control (Fink & Exner, 2019). Beyond disgust, mental contamination (i.e., feelings of internal dirtiness and pollution, caused by a person and that result in negative emotions, but without physical contact having occured) plays an important role, both in OCD patients and in healthy subjects, and can be evoked by thoughts, memories, images or statements (Fairbrother et al., 2005; Radomsky et al., 2018). The scenario used most often to induce mental contamination is imagining receiving a non-consensual kiss (De Putter, 2017; Fairbrother et al., 2005).
During the last decade, only a handful of methodologically sound studies on ImRs were published with OCD patient groups (Kip et al., 2023; Morina et al., 2017). One of them followed a single-case experimental design, and included patients who described intrusive OCD-related imagery (Veale et al., 2015). Whereas eight of the n = 12 patients had reliably improved their OCD symptoms after one session of ImRs, only one of them had reliably improved after the control session. However, the control intervention was always delivered first, and eleven patients had had previous CBT for OCD, which is why carry-over effects cannot be ruled out. Another single case study was implemented with a group of n = 18 OCD patients, and focused on guilt-inducing cognitions not necessarily related to the symptoms of OCD (Tenore et al., 2020). Up to three months following three ImRs sessions, and especially in the first week, the authors found significantly reduced OCD symptoms in this group of patients. By contrast, Maloney et al. (2019) included OCD patients with intrusive imagery in connection with individual symptom development (e.g., bullying, thoughts perceived as sexually inappropriate) who had not benefited sufficiently from previous CBT. Although OCD symptoms did not decrease after the control intervention (i.e., discussing the aversive memory), twelve of the n = 13 participants had reliably improved their OCD symptomatology after one session of ImRs, and this effect was maintained at one-month follow-up. However, subsequent single case studies should take specific statistical features (e.g., the number of measurements available, autocorrelation) that follow from this specific design more directly into account (Manolov et al., 2014).
Another sampling strategy that considers the resources available is that of using analogue participants. Analogue samples are valuable for investigating the mechanisms of different OCD treatments, and they often enable more precise experimental control (Abramowitz et al., 2014). A current RCT compared N = 198 participants (i.e., Amazon mTurk workers) with moderate OCD symptoms within three audio-guided groups: (1) ImRs on episodic future imagery, i.e., on a very unpleasant mental image of an individually relevant future OCD-related event, (2) imaginal exposure and (3) imagining an everyday activity (Cooper et al., 2023). In order to investigate the interventions on a low-threshold basis, the participants did not receive therapist support, but implemented the conditions in an online self-guided format. ImRs participants reported greater reductions, both in anxiety and fear, than those in the exposure group, whose values changed less than in the other two groups. Although participants in the ImRs condition reported greater reductions in disgust than participants in the exposure condition, there was no evidence of differences between the ImRs and control conditions on disgust (Cooper et al., 2023).
Despite a growing number of investigations on the efficacy of ImRs in OCD during the last few years, there is still a paucity of RCTs including different control groups. First of all, we investigated whether a newly developed spit-face scenario induced disgust and anxiety in the participants, i.e., analogue subjects reporting at least mild obsessive–compulsive (OC) symptoms. The spit-face scenario is an adaptation of the non-consensual-kiss paradigm (Millar et al., 2023). In the adapted version, subjects are confronted with an unpleasant smelling stranger who spits at them when he speaks (see Procedure). It was hypothesized that the spit-face scenario would induce disgust and anxiety (H1).
The objective of the randomized controlled study was then to investigate if there was lower disgust and anxiety in participants after an ImRs manipulation than in two control conditions (i.e., imagery focus, distraction). It was hypothesized that compared to those assigned to a control condition, participants assigned to ImRs would demonstrate a greater reduction in disgust and anxiety across sessions (H2).
Method
Participants
Participants were recruited from 29/03/2023 to 29/05/2024 via the University of Potsdam’s participant pool, social media and self-help groups. We included adult subjects (over 18 years old) who screened positive on the first item of the short form of the Dimensional Obsessive–Compulsive Scale (DOCS-SF; Kühne et al., 2021) as a single-item screener on contamination. Specifically, they had experienced unwanted and unpleasant thoughts about germs and contamination and/or repetitive behaviors or mental rituals to prevent contamination (e.g. washing, cleaning, showering) during the last month. Subjects were excluded if, before starting the online study, they self-indicated alcohol or drug addiction or current abuse, suffering from PTSD or psychosis, or if the indicated that their German language skills were insufficient to follow the experiment. If participants were students at our university, they received course credit. Moreover, subjects were informed that we donated 1€ for every completed participation to an association supporting children with cancer.
Measures
Demographic questionnaire. Participants were asked to provide information on their age, gender, education, whether they have previously undertaken psychotherapy and if a psychologist or physician has ever given them an OCD diagnosis.
State-Trait Anxiety Questionnaire—German State Short Form (STAI-SKD; Englert et al., 2011; Laux et al., 1981). The STAI-SKD is a 5-item measure for assessing state anxiety. Each item is rated on a four-point Likert scale ranging from 1 (“Not at all”) to 4 (“Very much”). The measure was used at baseline (T1), pre (T2) and post measurement (T3). The German translation displayed acceptable to good internal consistency (α = 0.76), and good convergent and divergent validity (Englert et al., 2011). In the current study, the STAI-SKD exhibited good to excellent internal consistency (αT1 = 0.88, αT2 = 0.92, αT3 = 0.92).
State-Disgust-Questionnaire—German Short Form (SDQ; Ihme & Mitte, 2009). The instrument is a 15-item questionnaire for measuring state disgust. Its items are rated on a four-point Likert scale ranging from 1 (“Not at all”) to 4 (“Very much”). The internal consistency of the questionnaire is excellent (α = 0.93). Evidence of its construct validity was provided by associations with trait disgust (r = 0.28) and state anxiety (r = 0.61; Ihme & Mitte, 2009). The questionnaire was used at baseline, pre and post measurement. Since the two inversely coded items 3 and 9 had deviating low corrected item-total correlations (ρXiR(i) < 0.37), we excluded them from further analysis. In the present study, the 13-item SDQ had excellent internal consistency (αT1 = 0.92, αT2 = 0.93, αT3 = 0.95).
Obsessive–Compulsive Inventory—Revised (OCI-R; Foa et al., 2002; Gönner et al., 2008). The OCI-R is an 18-item measure for screening for OCD symptoms. The items are rated on a five-point Likert scale ranging from 0 (“Not at all”) to 4 (“Very much”). The total score ranges from 0 to 72. Based on the total score, the severity of symptoms can be classified as mild (0–15), moderate (16–27) or severe (> 27; Abramovitch et al., 2020). The OCI-R was administered at post-measurement only. The total scale has good internal consistency (α = 0.81 to 0.93), and good convergent and divergent validity (Gönner et al., 2007, 2008). In the current study, the OCI-R exhibited good internal consistency as well (αT3 = 0.88).
Visual Analogue Scales (VAS). Such scales are frequently used in scientific research (van den Hout et al., 2019) because they are able to evaluate subjective constructs with great sensitivity. In this study, two visual analogue scales were used to measure state anxiety (“I feel anxious”) and state disgust (“I feel disgust”). These VAS were used at baseline, pre and post measurement.
For manipulation check, three further VAS on imagery (“How well did you manage to visualize the guided situation?”), vividness (“How vividly could you put yourself in the guided situation?”) and on the ability to follow the instructions (“How well were you able to engage with the instructions and prompts?”) were used. At T2 (post spit-face scenario), the VAS scales were used in all three conditions. At T3 (post manipulation), the VAS scales were only used in the Imagery focus and in the Distraction conditions. All items ranged from 0% (“Did not apply to me at all”) to 100% (“Applied to me very much”). Moreover, subjects were asked about distraction (“Were you distracted during the study?”) and avoidance (“Did you do anything to get rid of negative feelings during your participation in the study?”) at T3 using dichotomous variables (Yes, No).
Design
The study was approved by the University of Potsdam’s ethics review committee (no. 22/2022) and by its data security officer. The study protocol was preregistered with the Open Science Framework (Hobrecker & Kuüne, 2023) before data collection started. The study was conducted online, using our university’s survey tool. The RCT used a 3 (Group: ImRs, Imagery focus, Distraction) X 3 (Time: baseline (T1), pre (T2) and post measurement (T3)) design. More specifically, the disgust and anxiety measures were filled in before listening to the newly developed spit-face scenario (T1), afterwards (T2), and after having completed the manipulation (T3, see Fig. 1). Randomization was implemented directly within the survey tool. Based on an rmANOVA, f = 0.25, power = 0.80 and α = 0.05, the total sample size needed was N = 81 (G*Power 3.1.9.4; Faul et al., 2007).
Fig. 1
Flow chart of study inclusion and randomized group allocation (Focus = Imagery focus)
×
Procedure
Participants were first asked to give informed consent, to indicate that they felt physically and mentally able to participate, and to confirm that they were in a quiet environment and had the opportunity to listen to the audio recordings undisturbed. Then, they completed the demographic questionnaire, after which the baseline measures (T1; STAI-SKD, SDQ, VAS on anxiety and disgust) were administered (Fig. 1).
Spit-face scenario. Second, participants were instructed to listen to the audio imagination via headphones. We only included them if they had listened to the complete audio file. The imagination was adapted from the non-consensual-kiss scenario which was mostly used in female samples (De Putter, 2017; Fairbrother et al., 2005; Radomsky et al., 2018). During the original scenario, participants are instructed to imagine vividly and in detail being kissed by a stranger without their consent. In order to adapt the paradigm to trigger disgust and anxiety regardless of the participants’ gender and without the notion of sexual coercion, we developed a spit-face scenario. During the imagination, subjects also visualized a party scene, but were confronted with an unpleasant smelling stranger who speaks to them from a very close distance without the subject being able to exit the scene. As contact with a stranger's saliva is an important feature of the non-consensual-kiss paradigm (Millar et al., 2023), the stranger in our scenario repeatedly spits while speaking, and the participants repeatedly imagined being hit by his drops of saliva. We conducted a pilot trial with N = 14 therapists (7 licenced psychotherapists, 2 psychotherapists in training; 7 female, 7 male), and asked them for feedback on what they had imagined. As a consequence, we shortened the audio file, and simplified the instruction. The spit-face scenario and its English transcript are available from the first author.
Manipulations
It should be emphasized that the manipulations were not used as psychotherapeutic strategies but as three different manipulations as part of the experiment. The manipulations were created by one of the co-authors (CM) in consultation with the other authors.
Imagery rescripting. Afterwards, participants were randomized to one of three study groups. In the ImRs condition (8:15 min), participants were first asked to close their eyes and recollect the spit-face scenario by vividly imagining being at the party again. In order to elicit strongly disturbing emotions, the imagination was accompanied by questions such as "What do you hear?”, “What do you see?", “What do you feel?” (phase 1). According to Arntz and Weertman (1999), subjects were then instructed to enter their imagination from the perspective of a helping, supportive person, and to intervene and do whatever feels “right” (phase 2). In the third phase, participants were guided to imagine the scene from their first perspective again, and to evaluate how helpful the support was. If further help from the imagined supportive person was necessary, they were instructed to change the situation as appropriate.
Imagery focus. The imagery focus audio (8:23 min) started by recollecting the spit-face scenario with eyes closed (see phase 1 in ImRs). Then, an exposure-based manipulation based on Abramowitz (2018) followed (e.g., to go through the worst moment of the scenario, perceive the emotions, and learn to tolerate them). In doing so, subjects were instructed to reduce avoidance and safety behaviors (e.g., to do nothing to get rid of the emotions, not to distract oneself, not to think of anything else). At the end of the audio file, cognitive questions were used (e.g., to evaluate if emotions and cognitions have changed through the manipulation).
Distraction. During the audio (7:27 min), participants listened to psychoeducational contents adapted from a patient guidebook (Reinecker, 2006). They were given information on contamination-related OCD using a patient example. In order to focus their attention, subjects were informed that they would be asked three questions about OCD following the audio.
After having listened to the manipulation to which the participants had been randomized to, all subjects completed the post measures (T3, STAI-SKD, SDQ, VAS on anxiety and disgust), further manipulation check items, and the OCI-R.
Data analysis
Baseline differences between the three groups on demographic variables and the outcome measures were investigated using χ2-tests and univariate ANOVAs (Table 1), and on manipulation check items using t-tests and univariate ANOVAs (Supplement 1). To investigate whether the spit-face scenario had induced disgust and anxiety in the sample as a whole, we compared the baseline data (T1) with values obtained after listening to the scenario (T2), by using one-sided dependent samples t-tests.
Table 1
Baseline characteristics of the sample (N = 93; if not otherwise specified M, SD)
Variable
ImRs
(n = 34)
Imagery focus
(n = 25)
Distraction
(n = 34)
Test Statistics
Demographic variables
Age in years
27.06 (8.41)
25.84 (8.86)
27.79 (11.3)
F = 0.295, p = .745
Female (n)
73.5% (25)
76% (19)
82.4% (28)
Χ2 = 1.699, p = .791
OCD diagnosis (n)
23.5% (8)
24% (6)
32.4% (11)
Χ2 = 0.818, p = .664
Previous psychotherapy (n)
50% (17)
36% (9)
55.9% (19)
Χ2 = 2.336, p = .311
Outcome measures
SDQ-13
1.22 (.34)
1.41 (.48)
1.30 (.40)
F = 1.698, p = .189
VAS disgust
9.62 (12.82)
21.64 (21.46)
18.53 (28.19)
F = 2.526, p = .086
STAI-SKD
1.63 (0.56)
1.89 (0.66)
1.71 (0.67)
F = 1.241, p = .294
VAS anxiety
17.71 (22.32)
24.48 (22.3)
19.88 (23.06)
F = 0.626, p = .537
ImRs Imagery rescripting, VAS Visual analogue scale (0–100%), SDQ-13 State-disgust-questionnaire with 13 items (1 = not at all, 2 = somewhat, 3 = moderately so, 4 = very much), STAI-SKD State-trait anxiety inventory (1 = not at all, 2 = somewhat, 3 = moderately so, 4 = very much)
To examine the effect of the experimental vs. control conditions on disgust and anxiety, we used repeated measure ANOVAs (rmANOVAs) with the within-subject-factor Time (three measurements: baseline, pre, post) and the between-subject-factor Group (three groups: ImRs, Imagery focus, Distraction). According to Kolmogorov–Smirnov-tests, the majority of outcomes was not normally distributed. However, rmANOVA remains robust in non-normal distributions if skewness and kurtosis do not exceed specific values (i.e., skewness ≤ 2.31, kurtosis ≤ 8, Blanca et al., 2023a), which was the case in our data. To account for the degree to which sphericity was potentially violated, we referred to the multiplicative factor ɛ (Blanca et al., 2023b). More specifically, as ɛ was ≥ 0.60, we used the Huynh–Feldt correction to adjust the F-test (F-HF, Blanca et al., 2023b). The pairwise post hoc tests were corrected using the Benjamini–Hochberg procedure (Benjamini & Hochberg, 1995). The analyses were performed using SPSS Statistics 29 (IBM Corp., 2022) and Microsoft Excel, the level of significance was set at 0.05, and the effect sizes were indicated according to Cohen’s conventions (d = 0.2, small; 0.5, medium; 0.8, large; f = 0.1, small; 0.25, medium; 0.4, large; Cohen, 1992). According to the current ethics vote, data are available to other researchers upon scientific request.
Results
Descriptive results
Participants’ mean age was 27 years (SD = 9.6, range 18–72 years). The majority was female (77.4%, n = 72), 20.4% were male (n = 19), and two persons identified as non-binary (2.2%). In addition, the majority were students (75.3%, n = 70). Around a quarter (26.9%, n = 25) stated that a psychologist or physician had given them an OCD diagnosis before, and around half had previously undertaken psychotherapy (48.4%, n = 45). Participants indicated moderate obsessive–compulsive symptoms on the OCI-R (M = 24.84, SD = 11.82; Abramovitch et al., 2020). The three study groups did not differ significantly regarding demographic data, as well as baseline disgust and anxiety (Table 1). The same applied to the manipulation check items on imagery, vividness and on following instructions (Supplement 1). When they were given items on distraction and avoidance, 13% (n = 12) of the participants affirmed each item. The specific strategies the subjects used are listed in Supplement 1.
Disgust and anxiety induced by the spit-face scenario
After listening to the spit-face scenario, the participants perceived significantly more disgust (T2, t = − 11.038, p < .001, n = 93, M = 2.12, SD = 0.69), as measured with the SDQ-13 than before (T1, M = 1.30, SD = 0.40, d = − 1.15). Subjects also indicated significantly more disgust on the VAS at T2 (t = − 14.404, p < .001, n = 93, M = 61.17, SD = 26.68) than at T1 (M = 16.12, SD = 22.14, d = − 1.49).
Secondly, participants perceived significantly more anxiety after (t = − 3.459, p < .001, n = 93, M = 2.0, SD = 0.81) than before listening to the spit-face scenario (M = 1.73, SD = 0.63, d = − 0.36). Accordingly, subjects indicated significantly more anxiety on the VAS at T2 (t = − 3.803, p < .001, n = 93, M = 31.58, SD = 20.32) than at T1 (M = 20.32, SD = 23.06, d = − 0.39). Exploratively, we then examined whether participants perceived more disgust than anxiety at T2 on the VAS, which was confirmed (t = 11.717, p < .001, n = 93, d = − 1.22).
The effects of imagery rescripting vs. controls
Disgust, as measured with the SDQ-13, differed significantly by Time and by Time*Group interaction (Table 2). The post hoc tests showed that disgust was significantly higher at T2 (M = 2.34, SE = 0.137, p < .001) and T3 (M = 2.22, SE = 0.11, p < .001) than at T1 (M = 1.41, SE = 0.08) in the imagery focus condition. In the other two groups, disgust increased significantly from T1 to T2, and then decreased significantly towards T3 (Fig. 2). The same pattern was significant in VAS disgust (Table 2, Fig. 2).
Table 2
Results of the rmANOVAs including time (baseline, pre, post intervention) and group (ImRs, Imagery focus, Distraction)
Variable
F-HF
df
p
pBH
f
SDQ-13
Time
86.600
1.756
< .001
0.006
0.98
Time × Group
7.292
3.512
< .001
0.013
0.4
VAS disgust
Time
130.478
1.893
< .001
0.019
1.2
Time × Group
12.380
3.786
< .001
0.025
0.52
STAI-SKD
Time
10.047
1.794
< .001
0.031
0.33
Time × Group
1.898
3.588
.121
0.05
0.2
VAS anxiety
Time
11.311
1.626
< .001
0.038
0.36
Time × Group
2.716
3.253
.043
0.044
0.25
Bold values indicate p < .001
SDQ-13 State-disgust-questionnaire with 13 items, VAS Visual analogue scale (0–100%), STAI-SKD State-trait anxiety inventory, F-HF Huynh–feldt corrected F-tests, pBH = Benjamini–Hochberg corrected p-values (significant if p < .05)
Fig. 2
Graphs with means and standard deviations of all outcomes per group (ImRs = Imagery rescripting, Focus = Imagery focus, Distract = Distraction)
×
Anxiety, as measured with the STAI-SKD, differed according to measurement time, but not to Time*Group interaction (Table 2). Post hoc, anxiety was significantly higher after having listened to the spit-face scenario (T2, M = 2.03, SE = 0.08) than before (T1, M = 1.74, SE = 0.07, p = .002), and decreased significantly again from T2 to T3 (M = 1.78, SE = 0.07, p < .001) in the sample as a whole (Fig. 2).
Regarding VAS anxiety, there was a significant effect of Time and a significant Time*Group interaction (Table 2). Using post hoc tests, VAS anxiety increased significantly in the imagery focus group from T1 (M = 24.48, SE = 4.63) to T2 (M = 42.16, SE = 5.46, p = .008) and T3 (M = 43.88, SE = 5.09, p < .001). Nonetheless, it decreased significantly from T2 (M = 30.29, SE = 4.68) to T3 (M = 20.77, SE = 4.36, p = .005) in the distraction condition, whereas there were no significant changes in the ImRs group across the three measurements (Fig. 2).
Discussion
The present study investigated disgust and anxiety using a newly developed audio imagery that should be applicable regardless of the participants’ gender, and without the notion of a forced kiss, the spit-face scenario. Presented online and via audio, we then examined whether an ImRs manipulation reduced disgust and anxiety in subjects with obsessive–compulsive symptoms compared to two control conditions (i.e., imagery focus and distraction). First of all, the spit-face scenario induced feelings of disgust, comparable with watching a disgusting film, and with large effect sizes. Although anxiety was evoked as well, these effect sizes were significantly smaller, i.e., in the small to medium range. Around 70 to 79% of the participants were able to visualize the scenario vividly and follow the instructions well (Supplement 1). Altogether, the results support the assumption of validity of the spit-face scenario and its use in future studies. They are also needed to independently investigate the validity of the spit-face scenario, also at a greater temporal distance from the Covid pandemic.
Secondly, ImRs contributed significantly to a reduction of disgust. However, a psychoeducational audio reduced disgust equally, and except for VAS anxiety, subjects in the ImRs and distraction conditions reported quite similar patterns (Fig. 2). A major characteristic of ImRs is its strong experience activation (Ehring et al., 2022; Saulsman et al., 2019), but a similar reduction may indicate different underlying mechanisms. Altogether, our results underline the importance of choosing active control groups, which nevertheless do not contain the ImRs ingredient (Cooper et al., 2023). Furthermore, the results are in line with meta-analytical results, according to which, in comparison with active control groups, the effects of ImRs were very small to non-significant (Kip et al., 2023; Kroener et al., 2023).
Despite the instruction not to distract themselves, 13% of the participants reported having done so. They stated having been distracted for example by their mobile phone or their thoughts, or having avoided negative feelings by cleaning their desk or shaking hands, among others (Supplement 2). Considering again the result that participants in the psychoeducation condition indicated substantial relief, distraction was used to avoid negative feelings. While avoidance seemed less relevant in imagery focus, participants did not benefit from this manipulation, which indicates that its instruction should be changed, prolonged or repeated to enable habituation or inhibitory learning (Cooper et al., 2023). Moreover, future studies should include a more informative active control group, such as cognitive reappraisal, that was shown to reduce fear and disgust in the short-term in experimental settings (Olatunji et al., 2017; Shurick et al., 2012).
As distraction was a possible confounder in similar studies as well (Cooper et al., 2023), future study protocols could benefit from proactively instructing subjects on how to deal with distraction (e.g., to return to the intervention whenever thoughts wander) for all study groups. The importance of therapist-led training in the use of an audio intervention, and also in filling out questionnaire items, is supported by the remark of one participant at the end of the study: “For example, I had a different feeling when answering the questions than when listening to the audio. I very quickly got away from the feeling of the audio recordings and always had a very neutral feeling when answering questions, as I no longer related the questions to the audio recordings, but to the feeling afterwards” (P1607). As evidence from internet and mobile interventions shows, human support and guidance may reduce attrition and increase the effect of such interventions (Ebert et al., 2018). We thus assume that a certain level of clinical guidance could support participants in becoming less distracted and focusing more on the manipulation in a future study. From a clinical point of view, using online ImRs could supplement face-to-face CBT, for example as homework between weekly sessions (Cooper et al., 2023).
In our study, some limitations must be taken into account. Whereas the sample age ranged from 18 to 72 years, the vast majority was in young adulthood, female and students. Ethnicity was not surveyed. Although obsessive–compulsive symptom burden was present in our sample (e.g., moderate symptoms on the OCI-R, 26.9% with previous OCD diagnosis, 48.4% with previous psychotherapy), diagnoses were not confirmed by independent clinicians or by using a validated clinical interview. Therefore, future studies should include persons from more diverse ages, gender and ethnic backgrounds, and most notably, patients who received independent diagnostic interviews. Moreover, despite randomization, the Imagery focus group was smaller than the other study groups due to differential dropout. However, our study was among the first to investigate the differential effects of online self-administered imagery, highlighting both the feasibility as well as the challenges of those studies (Cooper et al., 2023). Using randomization and including active controls was methodologically stringent, but also associated with implementation challenges. Concluding from some open answers of our participants, systematically examining and comparing the negative effects of different interventions (Schulz et al., 2011) should be an important feature of subsequent online experiments, especially before their widespread use with patient groups.
The current expanded use of ImRs from PTSD and personality disorders to a broad spectrum of mental disorders also goes hand in hand with the need for RCTs that address the necessary vs. sufficient elements on the one hand, and the common vs. distinct mechanisms of change of effective ImRs on the other (Saulsman et al., 2019; Strachan et al., 2020). In one such study, mastery-based ImRs reduced anxiety (but not disgust) associated with episodic future images more than attachment-based rescripting, whereas no significant effects emerged if the target imagery was a mere memory (Cooper et al., 2024). Further studies of this kind are needed to adapt the manipulation to individual problematic areas. As “mental imagery can be both a problematic contributor to psychopathology and a potentially powerful tool for intervention” (p. 242), imagery techniques were conceptualized as a central component of CBT from the beginning, and have been returned to the focus of clinicians and researchers during the last decade (Saulsman et al., 2019). We advocate for further ImRs studies, especially in so-far under-researched fields such as OCD treatments.
Acknowledgements
We thank Brian Bloch for English language editing of the manuscript.
Declarations
Conflict of interest
The authors declare that they have no conflicts of interest.
Ethical Approval
The study was approved by the Potsdam’s ethics review committee (No. 22/2022) and by its data security officer.
Informed Consent
Written informed consent was obtained from all participants included in the study.
Human and Animal Rights
No animal studies were carried out for this study.
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