Mesmerizing memories: brain substrates of episodic memory suppression in posthypnotic amnesia.

Two groups of participants, one susceptible to posthypnotic amnesia (PHA) and the other not, viewed a movie. A week later, they underwent hypnosis in the fMRI scanner and received a suggestion to forget the movie details after hypnosis until receiving a reversal cue. The participants were tested twice for memory for the movie and for the context in which it was shown, under the posthypnotic suggestion and after its reversal, while their brain was scanned. The PHA group showed reduced memory for movie but not for context while under suggestion. Activity in occipital, temporal, and prefrontal areas differed among the groups, and, in the PHA group, between suggestion and reversal conditions. We propose that whereas some of these regions subserve retrieval of long-term episodic memory, others are involved in inhibiting retrieval, possibly already in a preretrieval monitoring stage. Similar mechanisms may also underlie other forms of functional amnesia.

Open-Label placebo for the treatment of unipolar depression: Results from a randomized controlled trial.

BACKGROUND: The response to placebo is robust in studies of various antidepressant treatments. The strong placebo response, combined with the absence of side-effects, has prompted suggestions to use the ethically sound open-label placebo (OLP) as a treatment for depression. The aim of the present study was to assess the efficacy of OLP as an adjunct to treatment as usual (TAU) in the setting of a randomized controlled trial for the treatment of unipolar depression. METHODS: Thirty-eight patients (age: 50 ± 17.1; 73.7% females) were randomized to either eight-week OLP treatment (n = 18) or four weeks of TAU followed by four weeks of OLP (n = 20). Clinical and socio-demographic measures were assessed at baseline, after four weeks, and at the end of the trial. Response to treatment was determined using the QIDS SR-16. RESULTS: There was an overall decrease in depression levels over time, F(2,35) = 3.98, p = .028. A significant group x time interaction was found only among non-geriatric patients (<65years) with an early onset of depression (<50years), F(2,22) = 3.89, p = .036. Post-hoc tests indicated a significant decrease during the first four weeks, but only in the OLP group, t(11) = 2.29, p = .043. LIMITATIONS: Small sample size and the use of a self-report questionnaire to assess depressive symptoms. CONCLUSIONS: Our findings support the possibility that OLP is an effective treatment for the relatively young population of depressed patients. Additional studies are warranted to explore the use of OLP in clinical practice.

Suggestibility as a predictor of response to antidepressants: A preliminary prospective trial.

BACKGROUND: The growing awareness that so many do not respond adequately to antidepressant (AD) pharmacotherapy has sparked research seeking to characterize those who do. While the pharmacological mechanisms of AD treatment have been extensively evaluated, much remains unknown about the placebo component of the response to medication. This study examined the association between suggestibility levels and response to ADs amongst depressed patients. METHODS: Twenty unipolar depression outpatients, recruited before starting AD monotherapy, received clear, standardized instructions that the therapeutic effects of AD, though not side effects, would require 2-4 weeks. At baseline (T1), 1 week (T2), and 1 month (T3), participants were evaluated for depressive symptoms, using the Hamilton Rating Scale for Depression-17 items (HAM-D); for anxiety by the Hamilton Rating Scale for Anxiety (HAM-A); for side effects by the Antidepressant Side Effect Checklist (ASEC); and for suggestibility, using the Multidimensional Iowa Suggestibility Scale (MISS). RESULTS: High levels of baseline suggestibility were associated with less improvement in depression level and more side-effects during the first week. In accordance with our hypothesis the more suggestible patients improved more between T2 and T3. No significant correlations were found between baseline suggestibility levels and change in anxiety. LIMITATIONS: Small sample size and a self-report questionnaire assessing suggestibility were limitations. CONCLUSION: This study offers a potentially new and clinically useful approach to understanding and predicting who will respond to AD treatment. Suggestibility seems to play a role, presumably by shaping expectation, in response to AD treatment. We hope that this avenue will be further explored.