D-cycloserine as adjunct to brief computerised CBT for spider fear: Effects on fear, behaviour, and cognitive biases.

BACKGROUND AND OBJECTIVES: In anxiety disorders, cognitive behavioural therapy (CBT) improves information-processing biases such as implicit fear evaluations and avoidance tendencies, which predicts treatment response. Thus, these cognitive biases might constitute important treatment targets. This study investigated (i) whether information-processing biases could be changed following single-session computerised CBT for spider fear, and (ii) whether this effect could be augmented by administration of D-cycloserine (DCS). METHODS: Spider-fearful individuals were randomized to receiving either 250 mg of DCS (n = 21) or placebo (n = 17). Three hours after drug administration, they received single-session computerized CBT, characterized by psychoeducation and exposure elements. Spider fear was assessed using self-report, behavioural, and information processing (Extrinsic Affective Simon Task & Approach Avoidance Task) measures at baseline (before drug administration), post-treatment, 1-day, and 1-month follow-up. RESULTS: Linear mixed-effects analyses indicated significant improvements on self-report and behavioural spider fear indices following CBT, but not on cognitive bias measures. There was no evidence of an augmentation effect of DCS on any outcome. Cognitive bias measures at 1-day were not predictive of 1-month follow-up spider fear in adjusted linear regression analyses. LIMITATIONS: Results might be biased by limited representativeness of the sample (high education and intelligence, largely Caucasian ethnicity, young age). The study was also only powered for detection of medium-sized DCS effects. CONCLUSIONS: These findings do not provide evidence for information-processing biases relating to treatment outcome following computerised CBT for spider fear or augmentation with DCS.

Evaluating the Clinical Utility of the Medical Symptom Validity Test (MSVT): A Clinical Series.

Performance validity tests (PVTs) are not widely used beyond medico-legal contexts in the UK. A UK survey suggests clinicians have reservations about their accuracy in clinical settings. This study sought to explore the validity of PVTs in an acute adult neuropsychology setting and to establish a potential "false positive" (FP) base rate. Failures on the Medical Symptom Validity Test (MSVT) in a consecutive clinical series of 405 patients were evaluated systematically and allocated to groups depending on clinical context. All failures were checked against the test's "dementia profile". Of the 405 participants, 329 passed the MSVT (81.2%), while 76 participants (18.8%) failed based on standard criteria. A 5.2% rate of potentially 'unexplained' failures was found. Other reasons for failure were classified as: presumed malingered neurocognitive dysfunction (4.6%), dementia/significant cognitive impairment (3.7%), technical/visual problems (1.8%), and "unexplained failure" with contributory factors (2.4%). These results suggest test specificity between 0.95 and 0.90. Most of the clinically significantly impaired patients matched the dementia profile (86.7%). Our results support the sensitivity, but not the specificity, of the dementia profile. However, approximately 1 in 20 patients failed the MSVT despite an otherwise unremarkable neuropsychological presentation; moreover, mood and pain may affect MSVT performance. Clinical implications for interpreting test scores are discussed.