False Memories in Schizophrenia.

Abstract

In prior studies, it was observed that patients with schizophrenia show abnormally high knowledge corruption (i.e., high-confident errors expressed as a percentage of all high-confident responses were increased for schizophrenic patients relative to controls). The authors examined the conditions under which excessive knowledge corruption occurred using the Deese-Roediger-McDermott paradigm. Whereas knowledge corruption in schizophrenia was significantly greater for false-negative errors relative to controls, no group difference occurred for false-positive errors. The groups showed a comparable high degree of confidence for false-positive recognition of critical lure items. Similar to findings collected in elderly participants, patients, but not controls, showed a strong positive correlation between the number of recognized studied items and false-positive recognition of the critical lure.Memory dysfunctions have been ascribed a key role in many pathogenetic models of schizophrenia (e.g., Hemsley, 1994). The literature suggests that both memory recall and recognition are severely compromised in schizophrenic patients relative to healthy participants (see Aleman, Hijman, de Haan, & Kahn, 1999, for a meta-analysis; see also Heinrichs & Zakzanis, 1998). However, as of yet, no schizophrenia-specific mnestic aberration has been identified. In contrast to an extensive body of research on forgetting in schizophrenia (i.e., false-negative errors), until recently the investigation of false-positive errors has attracted little attention. Depending on the paradigm used, some studies have provided evidence for enhanced false-positive memory errors in schizophrenia (Stirling, Hellewell, & Hewitt, 1997), whereas others have been unable to detect any group differences (e.g., Brébion, Amador, Smith, & Gorman, 1997;Moritz, Heeren, Andresen, & Krausz, 2001). Weiss, Dodson, Goff, Schacter, and Heckers (2002) have suggested that task demands and material may represent moderators for these inconsistent findings. In this study, increased false recognition in schizophrenia was evident for word, but not picture, material and only occurred in an experimental condition in which correct task performance necessitated retrieval of item-specific information (i.e., recollection of an item's spatial and temporal context).Another neglected area of memory research in schizophrenia is the investigation of memory confidence. In two source-monitoring studies Moritz, Woodward, & Ruff, 2003), evidence for a dissociation between objective and subjective memory performance in schizophrenia was found (i.e., measured performance accuracy vs. subjective evaluation of one's performance). Results from both investigations support the claim that patients with schizophrenia, irrespective of psychopathological status, display an enhanced confidence for false memory responses relative to healthy controls, whereas no group differences occurred for confidence in correct decisions. In the second study , 12% of responses made by schizophrenic patients with high confi...

High estradiol levels improve false memory rates and meta-memory in highly schizotypal women

“…Corlett et al (2009) extended these findings by including multiple schizotypy measures. In line with the findings of Moritz et al (2004;, highly schizotypal participants did not produce more false positives during recognition than those with low schizotypy. However, a positive correlation was found between schizotypy scores and confidence in false positive responses, particularly for subscales analogous to positive schizophrenic symptoms (e.g.…”

“…Thus, the proneness to false memories seems to be strongly related to the presence of delusions and a possible reason for the inconsistencies in present studies may be that some studies (e.g. Elvevåg et al, 2004;Moritz et al, 2004) did not differentiate between patients with and without delusions.…”

“…Typically, healthy participants falsely remember seeing the critical lure and / or new-related items ("false-positive response"; Roediger et al, 2001), during both the recall and the recognition test. Using this paradigm, it has been shown that while patients have poor recall abilities compared to healthy controls (increased forgetting, Elvevåg et al, 2004), they do not demonstrate increased false recognition (Elvevåg et al, 2004;Moritz et al, 2004). Using the same paradigm, Bhatt et al (2010) found that patients, both with and without delusions, made more false positive responses during recognition, compared to controls.…”

“…As a meta-cognitive measure of confidence in false memories, Moritz et al (2004) introduced the knowledge corruption index (KCI) defined as the proportion of high confidence responses that are errors. Employing the DRM paradigm, these authors found that while patients with schizophrenia and controls did not differ in number of false memories per se, patients made more high confidence errors both when forgetting items that were presented ("misses") and during false positive recognition.…”

Implicit false memory in the DRM paradigm: Effects of amnesia, encoding instructions, and encoding duration.

“…During the last decade, cognitive psychologists have started to look into the distortion of memory and the creation of "false" memories not only in healthy individuals, but also in specifically targeted groups, such as older people (e.g., Dehon, 2006), patients suffering from Alzheimer's disease (e.g., Budson, Sullivan, Daffner, & Schacter, 2003), amnesic patients (e.g., Schacter, Verfaellie, & Koutstaal, 2002), patients suffering from schizophrenia (e.g., Moritz, Woodward, Cuttler, Whitman, & Watson, 2004), patients with frontal lobe damage (e.g., Budson et al, 2002;Melo, Winocur, & Moscovitch, 1999), and so forth. The paradigm most often used for this type of research is the Deese/Roediger-McDermott (DRM) paradigm, developed by Deese in 1959, and revived by Roediger and McDermott in 1995. In this paradigm, participants study lists of words that are all semantic associations to a critical, but nonpresented "lure word."…”