. Author manuscript; available in PMC: 2019 Jun 1.

Published in final edited form as: Psychol Bull. 2018 Mar 19;144(6):584–640. doi: 10.1037/bul0000132

Table 3.

Summary of Findings of Studies Examining Peri-Event Predictors Included in Systematic Review

Study	Sample	N	Study Design		Independent Variable(s)	Intrusion Variables Reported (DVs)			Intrusion Assessment Timing			Intrusion Measurement			Main Findings	Effect Size (if reported)

			Ran	Pros		Freq	Distress	Other	During	7 day	Other	Monitor	Diary	Other
Peritraumatic Processing
Bourne et al. (2010)	Community	40	✔	✔	Visuospatial vs. verbal task vs. control	✔				✔			✔		Visuospatial → fewer intrusive memories than both verbal and control conditions	d = 0.80 (visuo vs. control
																d = 1.30 (visuo vs. verbal)
																d = 1.57 (verbal vs. control, study 2)
Brewin & Saunders (2001)	Undergrad	39	✔	✔	Visuospatial vs. no task	✔					✔ 2 wks		✔		Nonsig. associations
Halligan et al. (2002)	Undergrad	61	✔	✔	Data-driven vs. conceptual viewing instructions	✔	✔			✔				✔ Questionnaire	Nonsig. effect of processing condition on intrusive memory freq or distress
Holmes et al. (2004)^* (3 studies)	University	72/80/60	✔	✔	Study 1: Visuospatial vs. dot-staring vs. no task	✔				✔			✔		Visuospatial → fewer intrusive memories than no task and dissociation condition	d = 0.63 (visuo vs. control
																d = 1.03 (visuo vs. dot-staring)
															Nonsig. Association between dissociation and control	d = 1.03 (visuo vs. dot-staring)
					Study 2: Single key tap vs. overpracticed visuospatial vs. underpracticed visuospatial										Nonsig. Association between dissociation and control
															Underpracticed → fewer intrusive memories than control	d = 0.40 (under vs. control)
															Overpracticed → fewer intrusive memories than control	d = 0.35 (over vs. control)
					Study 3: Verbal interference vs. verbal enhancement vs. control										Verbal interference → more intrusive memories than control	d = 1.18 (interference vs. control)
															Nonsig. associations for enhancement and control	d = 1.18 (interference vs. control)
Kindt et al. (2008)^*	Undergrad (excluded indivs w/abuse histories)	73	✔	✔	Data-driven vs. conceptual viewing instructions	✔				✔			✔		Nonsig. association
Krans et al. (2010b)	University (excluded psychopathology)	54	✔	✔	Visuospatial vs. configurational task vs. no task	✔				✔			✔		Visuospatial → fewer intrusive memories than configurational and control	d = 0.78 (visuo vs. control
																d = 0.63 (visuo vs. config)
															Nonsig. association between configurational and control	d = 0.63 (visuo vs. config)
															Nonsig. association between configurational and control
Krans et al. (2010a)	University/ Community (excluded psychopathology)	86	✔	✔	Visuospatial vs. verbal vs. no task	✔				✔			✔	✔ IPT	Visuospatial and verbal → fewer intrusive memories than no task	d = 0.71 (visuo vs. control
Krans et al. (2010a)	University/ Community (excluded psychopathology)	86	✔	✔	Visuospatial vs. verbal vs. no task	✔				✔			✔	✔ IPT		d = 0.66 (verbal vs. control
Krans et al. (2013)^*	Undergrad (excluded psychopathology)	60	✔	✔	Visuospatial vs. verbal vs. no task	✔				✔	✔ 3 days		✔		Nonsig. associations
Laposa & Alden (2006)	Nurses w/ 1 yr experience in acute care	136	✔	✔	Medical focus vs. normal film viewing instructions	✔	✔			✔			✔		Medical focus → fewer intrusive memories	d = 0.41
Laposa & Alden (2006)	Nurses w/ 1 yr experience in acute care	136	✔	✔	Medical focus vs. normal film viewing instructions	✔	✔			✔			✔		Nonsig. association for intrusive memory distress	d = 0.41
Laposa & Rector (2012)^*	University (excluded psychopathology and history of any mental health treatment)	91		✔	CPQ	✔				✔			✔		Less self-referent processing → more intrusive memories when controlling for state dissociation and data-driven processing; not significant when post-anxiety added
Laposa & Rector (2012)^*		91		✔	CPQ	✔				✔			✔		Data-driven processing not a unique predictor
Logan & O’Kearney (2012)^*	University/ Community	105	✔	✔	Conceptual vs. sensory vs. no interference	✔	✔	✔	✔	✔	✔ Day of film viewing		✔		High trait anxiety + sensory interference → fewer intrusive memories compared to low trait anxiety + sensory interference day of film viewing; nonsig. effects on 7 day diary	d = 0.82 (day of film intrusive memory frequency)
																d = 0.66 (day of film intrusive memory distress)
															Nonsig. effects of conceptual interference on intrusive memory DVs
Morina et al. (2013)^*	Undergrad (excluded trauma hx, psychosis, MDD, current treatment)	67		✔	CPQ	✔	✔	✔	✔		✔ 5 days		✔	✔ Questionnaire	Higher data-driven processing associated with more intrusive memories, higher intrusive memory distress and vividness at all timepoints	Range: r = .30 – r = .42
Pearson & Sawyer (2011)	University/Community	24/36	✔	✔	Study 1: Visuospatial vs. nonspatial vs. no task	✔				✔			✔		Visuospatial and nonspatial → fewer intrusive memories than no task
					Study 1: Visuospatial vs. nonspatial vs. no task										High cognitive load → fewer intrusive memories regardless of task modality
					Study 2: High and low cognitive load for both visuospatial and verbal

Regambal et al. (2009)^*	Undergrad (excluded current treatment, MVA in last 6 mos)	148		✔	STAI-S CPQ	✔				✔			✔		Greater increases in negative emotions → more intrusive memories
Regambal et al. (2009)^*	Undergrad (excluded current treatment, MVA in last 6 mos)	148		✔	STAI-S CPQ	✔				✔			✔		Data-driven processing → more intrusive memories indirectly via maladaptive coping
Segovia et al. (2016)	Community	211	✔	✔	Organized vs. disorganized film clip; conceptual vs. data-driven vs. normal viewing instructions	✔	✔			✔			✔		Nonsig. effects of either manipulation on intrusive memory frequency and distress
Stuart et al. (2006)^*	University (excluded any mental health treatment)	20	✔	✔	Visuospatial vs. no task	✔				✔			✔		Visuospatial → fewer intrusive memories	η²= 0.34
Sundermann et al. (2013)^*	Community (excluded trauma history, depression, blood phobia)	51		✔	DDP	✔	✔				✔ wks; mos			✔ Phone interview	Higher data-driven processing → more intrusive memories at 2 wks but not 3 mos follow-up
White & Wild (2016)^*	University (excluded PTSD & MDD)	50	✔	✔	Abstract vs. concrete training	✔				✔			✔		Concrete training → fewer intrusive memories	d = 0.59
Context
Krans et al. (2013)	Undergrad (excluded psychopathology)	60	✔	✔	Context vs. no context information	✔				✔	✔ 3 day		✔		Context info → more intrusive memories only when no dual task being performed after 3 days
Krans et al. (2013)	Undergrad (excluded psychopathology)	60	✔	✔	Context vs. no context information	✔				✔	✔ 3 day		✔		Nonsig. differences for 7 day diary
Krans et al. (2016)	Undergrad/grad students (excluded psychopathology)	120	✔	✔	Moderate vs. severe outcome vs. no information	✔	✔	✔		✔	✔ 7^th day post		✔	✔ IPT	Severe outcome → more intrusive memories on provocation task than moderate and control conditions
Krans et al. (2016)	Undergrad/grad students (excluded psychopathology)	120	✔	✔	Moderate vs. severe outcome vs. no information	✔	✔	✔		✔	✔ 7^th day post		✔	✔ IPT	Nonsig. effect on intrusive memory frequency, vividness, distress via diary
Pearson (2012)	University (excluded psychopathology)	40	✔	✔	Contextual information vs. no information	✔		✔		✔			✔		Contextual information → more intrusive memories
Pearson (2012)	University (excluded psychopathology)	40	✔	✔	Contextual information vs. no information	✔		✔		✔			✔		Nonsig. effects on vividness, emotionality
Pearson et al. (2012)	University	40	✔	✔	Contextual information vs. no information	✔		✔		✔			✔		Contextual information → more intrusive memories	η²= 0.12
Pearson et al. (2012)	University	40	✔	✔	Contextual information vs. no information	✔		✔		✔			✔		Nonsig. effects on vividness, emotionality	η²= 0.12
Staugaard & Bernsten (2014)	University	32	✔	✔	Sound cue type (unique vs. repeated)	✔			✔					✔ Retrieva l phase	Unique sounds → more intrusive memories
Dissociation
Brewin & Saunders (2001)^*	Undergrad	39	✔	✔	Dissociation induction (visuospatial vs. distraction)	✔					✔ 2 wks		✔		Nonsig. association
Chou et al. (2014a)	Community (excluded psychopathology & MVA experience)	64		✔	Startle group (low, medium, high); HR change	✔		✔		✔			✔		Greater decrease in HR → increased intrusive memory vividness in low startle group only
Chou et al. (2014a)	Community (excluded psychopathology & MVA experience)	64		✔	Startle group (low, medium, high); HR change	✔		✔		✔			✔		Nonsig. effects on frequency
Dorahy et al. (2016)	Undergrad	60	✔	✔	Mirror staring vs. dot staring vs. neutral image M-PDEQ	✔	✔				✔ 3 days		✔		Dot condition → more intrusive memories than neutral on day 1 post-session
															Nonsig. effects on intrusive memory frequency on days 2, 3, and 3-day total
															Dot condition → more intrusive memory distress on day 1
															Both dissociation conditions → more distress on 3-day total
															M-PDEQ →more intrusive memories on day 1 and 3-day total
															M-PDEQ→ higher intrusive memory frequency on day 1, day 2, and 3-day total
Hagenaars & Krans (2011)^*	University (excluded psychopathology)	99		✔	DSS	✔				✔			✔		Nonsig. effect of DSS on intrusive memory frequency
Hagenaars et al. (2008)^*	University (excluded MDD & blood phobia)	79	✔	✔	Dissociative non-movement vs. deliberate non-movement vs. control	✔				✔			✔		Both non-mvement conditions → more intrusive memories
Hagenaars et al. (2008)^*	University (excluded MDD & blood phobia)	79	✔	✔		✔				✔			✔		Nonsig. differences between movement types
Holmes et al. (2004)^*	University	54/80/60	✔	✔	3-study sequence; DSS and HR assessed in each study	✔				✔			✔		Increases in state dissociation → more intrusive memories after controlling for dual task and trait anxiety in studies 1 & 2; nonsig. effect in study 3
Holmes et al. (2004)^*	University	54/80/60	✔	✔	3-study sequence; DSS and HR assessed in each study	✔				✔			✔		Greater reductions in HR over film → more intrusive memories in studies 1 & 2; nonsig. effect in study 3
Holmes et al. (2006)	University (excluded any mental health treatment)	16	✔	✔	Suggested dissociation vs. control	✔				✔			✔		Nonsig. association
Laposa & Rector (2012)^*	University (excluded psychopathology, treatment history history)	91		✔	PDEQ	✔				✔			✔		PDEQ did not significantly predict intrusive memories when self-referent processing and data-driven processing controlled for
Mairean & Ceobanu (2016)^*	University (excluded MVA experience)	148		✔	DSS	✔				✔			✔		State dissociation → more intrusive images but not thoughts
Mairean & Ceobanu (2016)^*	University (excluded MVA experience)	148		✔	DSS	✔				✔			✔		State dissociation did not mediate relationship b/w thought and emotion suppression and intrusive memories
Biological & Emotional Arousal
Cheung et al. (2015)^*	Undergrad	63	✔	✔	sAA and cortisol levels	✔		✔			✔ 2 days			✔ specific items from IES	Nonsig. associations between sAA, cortisol and intrusive memory freq using post-film saliva samples
Chou et al. (2014b)	University/Community (excluded psychopathology, treatment, MVA experience	58		✔	Cortisol levels; HR groups (accelerators & decelerators)	✔		✔		✔			✔		Higher peri-film cortisol → more intrusive memories only for accelerators but not decelerators	r = .53 (peri-film cort in accelerators)
Chou et al. (2014b)		58		✔	Cortisol levels; HR groups (accelerators & decelerators)	✔		✔		✔			✔		Lower post-film cortisol → more vivid intrusive memories	r = .53 (peri-film cort in accelerators)
Dunn et al. (2009)	Community (excluded current psychopathology, past PTSD)	89	✔	✔	Emotion suppression vs. acceptance vs. no regulation instructions	✔				✔			✔		Nonsig. associations between conditions and intrusive memories including when trait emotion regulation strategies controlled for
Dunn et al. (2009)	Community (excluded current psychopathology, past PTSD)	89	✔	✔		✔				✔			✔		Post hoc: greater proportion of zero intrusive memory days for suppress vs. other conditions
Hall & Bernsten (2008)	University	129		✔	STAI-S Intensity, valence, mood impact, dislike, bodily reaction, self-relevance of pictures	✔		✔			✔ 5 days		✔		Higher emotion during encoding → more memories of pictures (both voluntary and involuntary)
Holmes et al. (2004)^*	University	54/80/60	✔	✔	HR in 3-study sequence	✔				✔			✔		Greater reductions in HR over film → more intrusive memories in studies 1 & 2; nonsig. effect in study 3
Nicholson et al. (2014)	Trauma-exposed (mixed trauma)	58		✔	Norepinephrine Cortisol NE^*cort interaction PTSD vs. trauma-exposed vs. non-trauma exposed	✔					✔ 2 days			✔ Retrospective diary	NE^*cort → intrusive memories only in PTSD group
Nicholson et al. (2014)	Trauma-exposed (mixed trauma)	58		✔		✔					✔ 2 days			✔ Retrospective diary	Nonsig. associations for all other IVs and DVs
Wegerer et al. (2013)	University (excluded mental and neuro disorders)	66		✔	Fear conditionability (via SCR and subjective ratings)	✔			✔		✔ 2 days		✔	✔ IMQ	Higher fear conditionability → more intrusive memories 30 min post-task and in 2 days follow-up

Study Quality: “Ran” = randomized, “Pros” = prospective; DDP: Data-Driven Processing subscale of CPQ; LSRPS: Lack of Self Referent Processing Scale; CPQ: Cognitive Processing Questionnaire; STAI-S: State-Trait Anxiety Inventory- State; HR: heart rate; M-PDEQ: Modified Peritraumatic Dissociative Experiences Scale; DSS: Dissociative State Subscale; sAA: salivary alpha amylase; SCR: Skin conductance response; TMQ: Trauma Memory Questionnaire; IPT: Intrusion Provocation Task; IMT: Intrusive Memory Questionnaire

Study included multiple times in table due to presence of multiple predictors of intrusions