Review of source-monitoring processes in obsessive-compulsive disorder

Table 1 Details of studies investigating source monitoring in patients with obsessive-compulsive disorder or participants with subclinical compulsive symptoms

Ref.	SM subtype1	Samples (n)	SM task: Source encoding conditions	OCD relevant stimuli	Significant between-groups difference in SM performances	Significant between-groups difference in confidence
Hermans et al[24], 2003	Internal	17 OCD; 17 HC	ART: Imagining performing an action a fixed number of times + performing it a various number of times	Relevant compulsive + irrelevant compulsive + neutral actions	No difference between OCD and HC; No difference between high (n = 9) and low (n = 8) checkers	OCD < HC for neutral and irrelevant compulsive actions
Merckelbach et al[25], 2000	Internal	19 OCD; 16 HC	ART: Imagining performing vs performing actions	No	No difference between OCD and HC; No difference between OCD checkers (n = 7) and OCD noncheckers (n = 12)	OCD < HC. Negative correlation between DES scores and confidence in OCD but not in HC
Cougle et al[23], 2008	Internal	21 OCD checkers; 24 HC	ART: Imagining performing vs performing actions	Bothersome + nonbothersome actions	No difference between OCD checkers and HC in both free recall and recognition tests	OCD checkers < HC
Constans et al[22], 1995	Internal	12 OCD checkers; 7 HC	ART: Imagining performing vs performing actions within action sequences	Anxiety-eliciting + neutral objects	No difference between OCD checkers and HC	No difference
Ecker et al[19], 1995	Internal	24 OCD checkers; 24 HCIP + 48 LCIP	ART: Imagining performing vs performing vs imagining seeing vs subvocal rehearsal	Not specified	OCD < LCIP for free recall of performed actions and made more confusions between performed and imagined perform actions; HCIP: More misattributions of imagined actions as performed than LCIP	OCD checkers < HC, regardless of the instruction modality
McNally et al[20], 1993	Internal	12 OCD checkers; 12 OCD noncheckers; 12 HC	ART: Tracing vs imagining tracing vs seeing drawings or words	No	No difference between checkers and noncheckers	OCD noncheckers < HC for words or drawings they traced. OCD checkers and noncheckers < HC for words they imagined
Moritz et al[29], 2009	Internal	32 OCD; 32 HC	ART: Imagining vs performing actions	No	No difference between OCD and HC	No difference
	External	32 OCD; 32 HC	ART: Verbal vs nonverbal instruction (pictogram)		No difference between OCD and HC
Rubenstein et al[15], 1993	Exp 1a: Internal + Reality	20 CP; 20 HC	ART: Seeing vs performing vs writing actions	No	CP made more SM confusions than HC	NA
	Exp 3: Internal	20 CP; 20 HC	WRT (word pair completion): Reading a word pair vs generating the second word of a pair	No	CP made more SM confusions than HC	NA
Zermatten et al[21], 2006	Internal + Reality	19 CP; 35 nonCP	ART: Imagining performing vs performing vs imagining seeing vs seeing vs verbally repeating	No	CP misattributed more performed actions as seen than nonCP (significant correlation with OCI-R checking); No difference for misattribution of performed actions as imagined perform	No difference
Reese et al[26], 2011	Reality	20 OCD; 20 HC; 20 BDD	WRT: Imagining seeing vs seeing words	Neutral + negative + BDD-related + OCD-related words	No difference between OCD and HC	No difference
Sher et al[10], 1983	Reality	26 CP; 28 nonCP	WRT (word pair completion): Imagining the second word of a pair vs seeing it written	No	No difference between CP and nonCP	CP < nonCP
Brown et al[27], 1994	Reality	28 OCD; 21 HC	WRT: Imagining seeing vs seeing words	No	OCD > HC. Among OCD, checkers (n = 13) < cleaners (n = 9)	NA
Kim et al[28], 2009	External	14 OCD; 14 HC	WRT: Female vs male voices	No	OCD < HC	Cognitive confidence subscores of MCQ were significantly higher in the OCD group than the control group; No correlation between confidence scores and SM

¹Source-monitoring subtypes investigated in the selected studies were reclassified according to Source-Monitoring Framework as described in Johnson 1993. ART: Action recognition task; BDD: Body dysmorphic disorder; CP: Checking-prone subjects; DES: Dissociative Experience Scale; HC: Healthy controls; HCIP: High-checking inpatients; LCIP: Low-checking inpatients; NA: Not available; NS: Not significant; OCD: Obsessive-compulsive disorder; OCI-R: Obsessive-Compulsive Inventory- Revised; SM: Source monitoring; WRT: Word recognition task.