The DOI matches its Crossref record; 24 of the 24 references it cites were found in a registry or an index; none of the 25 sources its claims cite is checked for support yet.
D-Cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia
Open accessAbstract
Background Whereas some studies have shown clear evidence for an augmentation effect of d-cycloserine (DCS) on exposure therapy for anxiety disorders, other studies have shown weak effects or no effect at all. Some preclinical data suggest that the DCS augmentation effect is moderated by the success of the extinction trials. Therefore, we conducted a re-analysis of existing data to examine whether the effects of DCS on clinical outcome would vary as a function of response to the exposure session (i.e. exposure success). Methods In a clinical trial, patients with height phobia received two sessions involving 30 minutes of virtual reality exposure therapy and were randomly assigned to a pill placebo (N=14) or 50 mg of DCS (N=15) immediately after each session. Results Mixed-effects regression analysis showed that the effects of DCS administration on clinical improvement was moderated by the level of fear experienced just prior to concluding exposure sessions. Patients receiving DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo when subjective fear was low at the end of the exposure. In contrast, when end fear was still elevated, patients receiving DCS improved less compared to those receiving placebo. Conclusions DCS appears to enhance the benefits of exposure treatment when applied after a successful session, but it seems to have detrimental effects when administered after inadequate/unsuccessful exposures. Trial Registry The Trial is registered at ClinicalTrials.gov (NCT01102803).
Overview
AI snapshot
Written from the paper’s full text.
TL;DR
In a re-analysis of a null trial of post-session D-cycloserine (DCS) for height phobia, DCS augmentation of exposure therapy depended on how much fear remained at the end of the exposure session. DCS improved outcome when end fear was low but worsened outcome relative to placebo when end fear remained elevated.
Key findings
- The effect of DCS vs. placebo on next-session CGI-I was moderated by prior-session end fear: interaction β = −.05, t(50) = 2.84, p = .007.
- At end fear = 0 (“no fear”), DCS-treated patients were rated almost 1 full point more improved on CGI-I than placebo-treated patients: β = .99, t(44) = 2.10, p = .04.
- At end fear = 36 (mean + 1 SD), DCS-treated patients were rated .84 points less improved on CGI-I than placebo-treated patients: β = −.84, t(48) = 2.75, p = .025.
- Among DCS-treated patients, higher prior-session end fear predicted worse current CGI-I: β = .03, t(48) = 2.43, p = .019; this relation was not significant for placebo (p = .12).
Methods
- Re-analysis of a clinical trial in which 29 medication-free adults with DSM-IV-TR acrophobia (mean age = 33.38; 76% female) received two sessions of 30 minutes of virtual reality exposure therapy and were randomized to placebo (N = 14) or 50 mg DCS (N = 15) immediately after each session.
- End fear was the subjective units of distress rating just before concluding each exposure session; clinical improvement was indexed by the clinician-rated CGI-I at the beginning of the next session/posttreatment.
- Mixed-effects regression predicted CGI-I from drug condition, prior-session end fear, and their interaction, controlling for baseline CGI-S, beginning fear, and number of virtual floors passed; models used full information maximum likelihood, Satterthwaite correction, and an unstructured covariance matrix.
Limitations
- The paper states the sample was relatively small, only post-session 50 mg DCS was examined, dose-response and timing cannot be inferred, and the analysis was post-hoc proof-of-concept requiring replication in larger and more diverse samples with other anxiety disorders.
- The paper also notes uncertainty about whether end fear or within-session fear reduction is the critical moderator, and that pre-session dosing may still offer more powerful DCS augmentation than post-session dosing.
- Evident from the text: all dropouts were in the placebo condition, and the sample was restricted to adults with height phobia.
Model-written summary. Check it against the paper before relying on it.
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Claims the paper makes
15 Not checked yet · 11 Own method · 7 Own result · 6 Own interpretation
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“we found that the relation between end fear at the previous session and CGI-I at the current session was not significant for participants in the Placebo condition [p=.12].”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Mixed-effects regression analysis showed that the effects of DCS administration on clinical improvement was moderated by the level of fear experienced just prior to concluding exposure sessions.”
- Also stated in: § Results · plain
“As hypothesized, the effect of pill administration (DCS vs. Placebo) on CGI-I at the beginning of the next session was moderated by the session end fear level [β= −.05, t (50) = 2.84, p = .007 for the interaction between condition and end fear level].”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Abstract > Results
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
- Also stated in: § Results · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In contrast, when end fear was still elevated, patients receiving DCS improved less compared to those receiving placebo.”
- Also stated in: § Results · plain
“For participants who reported end fear at 1 SD above the mean of the sample (end fear = 36), those receiving DCS were rated .84 points less improved on the CGI-I than those receiving placebo [β = −.84, t(48) = 2.75, p = .025].”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Abstract > Results
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
- Also stated in: § Results · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Patients receiving DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo when subjective fear was low at the end of the exposure.”
- Also stated in: § Results · plain
“For patients reporting an end fear of 0 [“no fear”], those receiving DCS were rated almost 1 full point more improved on the CGI-I than those receiving placebo [β = .99, t (44) = 2.10, p = .04].”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Abstract > Results
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
- Also stated in: § Results · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, for those receiving DCS, the relation between prior session end fear and current session CGI-I was significant [β = .03, t(48)= 2.43, p = .019], with higher end fear being associated with higher (worse) CGI-I at the next session.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
None of the sources cited for this claim have been checked yet.
In the paper
“Likewise, in a re-analysis of a null-finding study (3) of DCS augmentation, Bouton and colleagues (8) subsequently performed a median split of their sample based on the extinction effects during the drug session; again, a significant DCS augmentation effect was seen only for the animals that had demonstrated stronger extinction learning.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
- Not checked yetcites [3] Woods, 2006, D-cycloserine facilitates extinction but does not eliminate renewal of the conditioned emotional response, Behav Neurosci source
- Not checked yetcites [8] Bouton, 2008, D-cycloserine facilitates context-specific fear extinction learning, Neurobiol Learn Mem source
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“We found that 50 mg of DCS administered following each of two sessions of 30 minutes of graded virtual reality exposure did not result in better overall clinical outcomes than identical exposure combined with placebo administration (15).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
- Not checked yetcites [15] Tart, 2013, Augmentation of exposure therapy with post-session administration of D-cycloserine, J Psychiatr Res source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Specifically, both Lee and colleagues (9) and Bouton and colleagues (8) found that DCS augmentation was evident only when a sufficient number of trials was offered for extinction learning.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
In the paper
“A number of animal studies have investigated the limits of DCS augmentation effects and indicate that augmentation effects are achieved only with animals that have demonstrated extinction at the time the DCS is administered.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
- Not checked yetcites [4] Weber, 2007, Effects of D-cycloserine on extinction of learned fear to an olfactory cue, Neurobiol Learn Mem source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Hence, whether DCS has beneficial or detrimental effects appears to be linked with the sufficiency of fear learning achieved during (extinction) training.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
hedgedcorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Probably not a substantial claim. 15
- It may state two separate claims as one. 13
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“We observed considerable variability in end fear ratings (M=21.84; SD=14.54; range: 0-62) and CGI-I scores (M=2.57; SD=0.98; range: 1-4)”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“but the mean scores indicated that, on average, patients showed reasonable fear extinction and improvement in clinical status, with no evidence of worsening in clinical status (i.e., no participant was rated higher than “4” on the CGI-I).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
None of the sources cited for this claim have been checked yet.
In the paper
“Some preclinical data suggest that the DCS augmentation effect is moderated by the success of the extinction trials.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Abstract > Background
What the sources say
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“Importantly, Lee and colleagues (9) also found evidence for DCS augmentation of fear reconsolidation when extinction trials were limited; subjects that had received only limited cue exposure showed an increase in fear during a subsequent test.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
- Not checked yetcites [9] Lee, 2006, Reconsolidation and extinction of conditioned fear: Inhibition and potentiation, J Neurosci source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“The CGI-S and CGI-I are widely used measures of global psychopathology severity and improvement initially developed for the study of psychotropic drugs (16).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Measures
What the sources say
- Not checked yetcites [16] Guy, 1976
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Eligible participants received two sessions involving 30 minutes of virtual reality exposure therapy and were randomly assigned to one of two blinded arms: (1) administration of pill placebo immediately after each session (N=14) or (2) administration of 50 mg of DCS after each session (N=15).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Study Design and Treatments
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“Preclinical research indicates that the effect of DCS is to enhance whatever emotional learning has occurred; without sufficient extinction learning on drug, there is no or little beneficial outcome to enhance (8).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
What the sources say
- Not checked yetcites [8] Bouton, 2008, D-cycloserine facilitates context-specific fear extinction learning, Neurobiol Learn Mem source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“We used the Clinical Global Impressions Improvement scale, an established clinician-rated measure for measuring improvement in clinical trials (16), to index improvement in height phobia severity.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Introduction
What the sources say
- Not checked yetcites [16] Guy, 1976
boosted- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The observed effects were clinically meaningful, with CGI-I scale score differences between DCS and placebo estimated to be 1 point for those reporting very low fear (i.e., “0”) at the end of the previous session, and .84 points in the opposite direction for patients reporting fear at 1 SD above the sample mean (i.e., “36”) at the end of the previous session.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“VRE was manualized, administered by advanced doctoral students, and supervised by the first and last authors (JAJS and CDT).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Study Design and Treatments
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“If replicated and extended using data from studies validating the efficacy of pre-session DCS dosing, the results of the present study provide the basis for developing an algorithm for the application of DCS in conjunction with exposure therapy for the anxiety disorders.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Finally, our study represents a post-hoc analysis that, at best, provides proof-of-concept evidence for post-session dosing of DCS as combined with judicious selection of which sessions should be followed by DCS administration.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“There were no between-group (DCS vs. Placebo) differences on any of the demographic variables or any of the indices of clinical severity assessed at baseline (see Table 1).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“DCS appears to enhance the benefits of exposure treatment when applied after a successful session, but it seems to have detrimental effects when administered after inadequate/unsuccessful exposures.”
- Also stated in: § Discussion · hedged
“Consistent with prediction, our results indicated that, when end fear was low (i.e., high extinction learning), patients who received DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo. Conversely, when end fear was higher (i.e., lower extinction learning), patients receiving DCS showed significantly less subsequent improvement in symptom severity”
- Also stated in: § d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia · plain
“D-cycloserine enhancement of fear extinction is specific to successful exposure sessions: evidence from the treatment of height phobia”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Abstract > Conclusions
plainconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
- Also stated in: § Discussion · hedged
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“2 patients only had one data point because they dropped out of the study before they could be assessed on CGI-I after the second exposure session, 26 patients had two data points, and one patient dropped out between the first exposure and the follow-up session, thereby contributing no data to the analysis.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Data Analysis
plainn = 26- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“All dropouts were in the placebo condition.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Data Analysis
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“First, the sample size was relatively small.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Second, we only examined post-administration of 50 mg of DCS, and therefore cannot make inferences with respect to dose-response or timing of administration effects.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Finally, the MRM model used full information maximum likelihood estimation and the Satterthwaite correction for calculating degrees of freedom (resulting in different degrees of freedom for the tests of the significance of each regression coefficient).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Data Analysis
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“All capsules were identical in appearance to maintain the blind.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Study Design and Treatments
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
None of the sources cited for this claim have been checked yet.
In the paper
“Moreover, insufficient exposure may also set the stage for reconsolidation of active fear memories (23), and there is evidence that DCS may be able to enhance these adverse reconsolidation effects as well, leading to poorer outcome relative to placebo administration, as potentially observed in this and other studies (9, 24).”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Discussion
What the sources say
- Not checked yetcites [23] Eisenberg, 2003, Stability of retrieved memory: Inverse correlation with trace dominance, Science source
- Not checked yetcites [9] Lee, 2006, Reconsolidation and extinction of conditioned fear: Inhibition and potentiation, J Neurosci source
- Not checked yetcites [24] Lee, 2009, D-cycloserine potentiates the reconsolidation of cocaine-associated memories, Learn Mem source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“We also included the following control variables: baseline severity (CGI-S, assessed the week before the first exposure session), fear level at the beginning of the previous exposure session, and number of virtual floors successfully “passed” during the previous session.”
- Also stated in: § Discussion · hedged
“Third, our analyses indicated that the fear level reported just prior to concluding exposure interacted with DCS to predict clinical improvement, while controlling for fear at the beginning of the session, number of floors successfully passed during exposure and baseline clinical severity.”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Methods and Materials > Data Analysis
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
- Also stated in: § Discussion · hedged
The paper relies on this without support.
The fear rating provided just prior to concluding an exposure session is a valid index of exposure success (fear extinction), with lower ratings indicating greater success.
“we used the fear rating patients provided just prior to concluding the exposure exercises as an index of exposure success, with lower end fear ratings indexing evidence of fear extinction and higher end fear ratings indexing relatively unsuccessful fear extinction.”
“The fear rating provided just prior to concluding the exposure exercises was used as an index for exposure success (i.e., fear extinction), with lower ratings indicating higher success, and higher ratings indicating lower success.”
The paper relies on this without support.
Findings from animal studies on the moderation of DCS augmentation by extinction success generalize to human exposure therapy for anxiety disorders.
“These findings have direct application to the understanding of the differential effects of DCS augmentation observed in clinical studies with humans.”
“We used studies reporting the re-analyses of null results with animals (4, 8) as a model for a re-analysis of a null trial of DCS augmentation in humans (15).”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“However, more recent reports from the latter group suggest that the effectiveness of DCS as an adjunct therapy may be related to the degree of fear reduction observed during individual exposure therapy sessions (76, 77)”
From Conditioned fear associated phenotypes as robust, translational indices of trauma-, stressor-, and anxiety-related behaviors (2014) · cites this paper as [77]
Statistics that don’t add up
Each reported p-value recomputed from its test statistic and degrees of freedom.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
“t(48) = 2.75, p = .025”
§ d-cycloserine Enhancement of Fear Extinction is Specific to Successful Exposure Sessions: Evidence from the Treatment of Height Phobia > Results
Reported p = .025 · recomputed p = .008
Statistics recomputed
Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.
- Doesn’t add upt(48) = 2.75reported p = .025 · recomputed p = .008
“t(48) = 2.75, p = .025”
- Consistentt(50) = 2.84reported p = .007 · recomputed p = .007
“t (50) = 2.84, p = .007”
- Consistentt(44) = 2.1reported p = .04 · recomputed p = .041
“t (44) = 2.10, p = .04”
- Consistentt(48) = 2.43reported p = .019 · recomputed p = .019
“t(48)= 2.43, p = .019”
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Self-check results appear here once an independent check has confirmed them.
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Metadata
- Authors
- Smits, J. A. J., Rosenfield, D., Otto, M. W., Powers, M. B., Hofmann, S. G., Telch, M. J., Pollack, M. H., & Tart, C. D.
- Affiliations
- Southern Methodist University (US)
- Boston University (US)
- The University of Texas at Austin (US)
- Rush University Medical Center (US)
- Raymond G. Murphy VA Medical Center (US)
- Corresponding author
- Smits, Jasper A.J.
- ORCID
- Venue
- Biological Psychiatry
- Publisher
- Elsevier BV
- Published
- 2013-06
- Volume
- 73
- Issue
- 11
- Pages
- 1054-1058
- ISSN
- 0006-3223 (ISSN-L)
- PMC
- PMC3636175
- OpenAlex
- W2072549054
- Semantic Scholar
- 7ae003f1050ed9b66eb493693ded742d52930519
- Cited by
- 142
- References
- 24
- Citations by year
- 2026: 1 · 2024: 1 · 2023: 4 · 2022: 7 · 2021: 3 · 2020: 6 · 2019: 9 · 2018: 22 · 2017: 22 · 2016: 13 · 2015: 19 · 2014: 24 · 2013: 11
- FWCI
- 30.25
- Type
- journal article
- Language
- en
- Open access
- green
- europepmc.org
- Locations
- Biological Psychiatry (publishedVersion)
- PubMed (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institute of Mental Health (R01MH075889)
- Topics
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Anxiety, Depression, Psychometrics, Treatment, Cognitive Processes
- Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
- Social Sciences › Psychology › Clinical Psychology › Posttraumatic Stress Disorder Research
- Keywords
- D-cycloserine, fear extinction, exposure therapy, virtual reality exposure therapy, treatment response, anxiety disorders
- MeSH terms
- Adult, Cycloserine, Double-Blind Method, Extinction, Psychological, Fear, Female, Follow-Up Studies, Humans, Male, Phobic Disorders, Regression Analysis, Severity of Illness Index, Virtual Reality Exposure Therapy
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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