Individuals with psychotic-like experiences exhibit enhanced involuntary autobiographical memories

Involuntary Autobiographical Memory in Alzheimer's Disease: A Double-Edged Way of Remembering the Past?

Background

Alzheimer's disease (AD) is characterized by severe memory alterations, affecting especially memories of personal past events. Until now, autobiographical memory impairments have been characterized using formal memory assessments, requiring patients to strategically and deliberately recall past events. However, contrary to this highly cognitively demanding mode of memory recall, autobiographical memories frequently come to mind unexpectedly based on automatic associative processes. The involuntary recall of personal memories is effortless and possibly represents a preserved way for AD patients to remember past events.

Objective

This study aimed to investigate involuntary autobiographical memory in AD patients and compare the characteristics of these memories with those of healthy controls.

Methods

Involuntary autobiographical memory was measured in 24 AD patients and 24 matched control participants using self-report measures. Participants were asked to report the frequency with which involuntary autobiographical memories were experienced in their daily life and to describe and self-assess one example of an involuntary memory.

Results

We showed that AD patients and control participants did not differ in terms of the frequency or subjective characteristics of their involuntary autobiographical memories in daily life, except for feelings of intrusiveness. Compared to control participants, AD patients reported their involuntary autobiographical memories as being more intrusive. In addition, more negative and vague involuntary autobiographical memories were associated with greater depressive symptoms.

Conclusions

These findings open up a new avenue for research to better understand the extent to which involuntary autobiographical memory might be preserved in AD patients and why these memories may in turn become intrusive to patients.

Mental time travel for self and others in individuals with a high level of schizotypy

Mental time travel (MTT) is the ability to project oneself to the past or future through mental simulation. Moreover, MTT can involve self-related or other-related information. This study aimed to compare MTT in individuals with high levels of schizotypy and that in their counterparts with low levels of schizotypy. Participants with high (n = 37) and low (n = 37) levels of schizotypy completed an MTT task with four conditions [2 (Condition: self vs. other) × 2 (Time orientation: past vs. future)]. They were required to recall past events that had happened to themselves or to a non-intimate person, and to imagine possible future events that might happen to themselves or to a non-intimate person, related to cue words. Outcome measures included specificity, vividness, sense of experience, emotional valence, emotional intensity, proportion of first-person visual perspective in events, and difficulty in event generation. A 2 (Group: high vs. low levels of schizotypy) × 2 (Condition) × 2 (Time orientation) mixed analysis of variance was conducted on each index. Results showed that self-related MTT was more specific than other-related MTT in low levels of schizotypy participants but not in high levels of schizotypy participants. Participants with a high level of schizotypy reported fewer specific events, and reported events with lower vividness and positive emotion than did those with a low level of schizotypy. Self-related MTT showed higher levels of phenomenological characteristics than did other-related MTT. In conclusion, individuals with a high level of schizotypy have altered MTT, and cannot benefit from the self-advantage effect on the specificity of MTT.

Autobiographical memory and the self on the psychosis continuum: investigating their relationship with positive- and negative-like symptoms

Autobiographical memory is severely impaired in schizophrenia, but previous work has largely treated both as unitary concepts. Here, we examined how various dimensions of autobiographical memory relate to different aspects of psychosis. Participants were recruited from the general population (Study 1, N = 264) and a university subject pool (Study 2, N = 305). We examined different measures of autobiographical memory and self (i.e., involuntary memory, autobiographical recollection, self-knowledge and self-awareness), at the trait level in Study 1 and both trait and state levels in Study 2, as a function of positive-and negative-like symptoms of psychosis. Across both studies, positive and negative dimensions of psychosis were found to be related to an increase in involuntary memories (i.e., the spontaneous recall of personal memories), and to lower self-concept clarity and insight. Positive and negative dimensions of psychosis correlated differently with autobiographical recollection characteristics, measured at both trait (Studies 1 and 2) and state levels (Study 2). Positive-like symptoms (in particular hallucination-proneness) showed a stronger and more consistent pattern of correlations than negative-like symptoms. These findings call for a dimensional approach to the relationship between autobiographical memory and psychosis symptoms in clinical and non-clinical individuals, to better understand the breakdown of autobiographical memory in the psychopathology of psychosis.

Sexual assault and psychosis in two large general population samples: Is childhood and adolescence a developmental window of sensitivity?

BACKGROUND

Research has shown a strong relationship between psychosis and sexual assault. Theories on developmental trauma as a causal factor for psychosis suggest that exposure to sexual trauma in childhood would have a stronger association with psychosis than sexual trauma in adulthood. We hypothesized that exposure to sexual trauma earlier in childhood and adolescence would be more strongly associated with hallucinations, delusional beliefs and psychotic disorder than sexual trauma that occurred later in life.

METHODS

Using the 2007 and 2014 Adult Psychiatric Morbidity Surveys (N = 14,949) we calculated the prevalence of sexual assault, hallucinations, delusional beliefs, and psychotic disorder. We used logistic regression to examine the relationship between age of exposure to sexual assault (first exposure <16 vs first exposure ≥16) and odds of hallucinations, delusions, and psychotic disorder.

RESULTS

Sexual assault at any age was associated with an increased odds of hallucinations (aOR = 2.00, 95%CI = 1.63-2.46), delusional beliefs (aOR = 2.55, 95%CI = 2.24-2.89) and psychotic disorder (aOR = 5.28, 95%CI = 3.59-7.76). There was no significant difference, however, in the prevalence of hallucinations, delusional beliefs or psychotic disorders in individuals first exposed to sexual assault <16 and individuals first exposed ≥16.

CONCLUSIONS

Contrary to our hypothesis, we did not find evidence that exposure to sexual assault in childhood and adolescence was more strongly associated with hallucinations, delusional beliefs or psychotic disorder than exposure to sexual assault age >16. Our findings do not support the idea that childhood and adolescence are uniquely sensitive periods for the emergence of psychotic experiences or psychotic disorder in relation to sexual trauma.

Emotional autobiographical memory impairment features in three mental disorders

We proposed the Emotional Autobiographical Memory Test (EAMT) as a specialized method for measuring emotional autobiographical memory impairment in patients with mental disorders. The EAMT was tested with 32 patients with schizophrenia, 18 patients with bipolar disorder, 32 patients with depression, and 42 people undiagnosed with such disorders. We extracted 13 indices of five kinds of features from participants' emotional autobiographical memory and compared them among the four groups. The overgeneralization result in the schizophrenia and depression groups was consistent with previous results, supporting the EAMT's validity. However, inconsistent with previous results, overgeneralization was not found in the bipolar disorder group. Further, the count of involuntary memories in the patient groups (vs. control group) was significantly smaller, which can guide future researchers in investigating the psychopathology of mental disorders.

Unraveling the role of retrieval deficits in autobiographical memory impairment in schizophrenia: A comparison of involuntary and voluntary autobiographical memories

Patients with schizophrenia show severe autobiographical memory impairment, thought to reflect retrieval deficits caused by executive dysfunction. However, prior research has focused exclusively on strategic (voluntary) retrieval, and ignored involuntary retrieval resulting from automatic and associative processes, involving minimal cognitive control. We report two studies with patients diagnosed with schizophrenia (Ns = 40 and 50 respectively) comparing their impairment in involuntary versus voluntary autobiographical memory. We use two different methodologies, not previously used in schizophrenia research: a naturalistic study involving real-life data and an experimental setup. Both studies consistently showed that involuntary and voluntary autobiographical memories were similarly impaired in schizophrenia. The absence of interaction effects between group and retrieval suggests that schizophrenic patients did not benefit from memory tasks involving little retrieval effort. These findings suggest that autobiographical memory impairment in schizophrenia are not caused by problems with self-initiated voluntary retrieval, but instead likely reflect encoding or binding deficits.

Involuntary Autobiographical Memories in Schizophrenia: Characteristics and Conditions of Elicitation

Involuntary autobiographical memories are mental representations of personally experienced past events that come to mind spontaneously, with no preceding attempt to recall them. They have been showed to be more frequent and more emotional in the psychosis continuum. Although schizophrenia is strongly associated with thought disorders, including cognitive intrusions of thought, images, semantic knowledge, research on patients' involuntary autobiographical memories is limited. We undertook two studies to compare involuntary and voluntary remembering in schizophrenia and the conditions in which involuntary memories occurs in those patients, both in daily life (n = 40), using a diary method, and in an experimental context (n = 50). Overall, results showed that the conditions of elicitation of involuntary memories differ in patients, as patients were more sensitive to memory triggers, especially internal triggers, in comparison to controls. Relatedly, patients' involuntary memories-mostly related to mundane events with low emotional load-were experienced more frequently. Although patients' involuntary and voluntary memories were less clear, more poorly contextualized and associated with a lower belief in occurrence than those of controls, patients considered them as more central to the self, in comparison to controls. The results are discussed in relation to patients' self-reflective impairments.

Involuntary mental time travel in individuals with schizotypal personality features

Involuntary mental time travel (MTT) refers to the phenomenon of mentally reliving past experiences or pre-living possible future events in an involuntary form. Few studies have explored involuntary MTT in individuals with schizotypal personality features. The present study aimed to first explore the psychometric properties of the Involuntary Autobiographic Memory Inventory (IAMI) in a Chinese sample (Study 1), and then to explore whether individuals with schizotypal personality features experience involuntary MTT more frequently than individuals without schizotypal features. Moreover, the study explored whether the aberrant frequency of involuntary MTT is correlated with positive schizotypal features (Study 2). The results showed that the IAMI had good structural validity and reliability in a Chinese sample. Individuals with schizotypal traits reported a significantly higher frequency, less positive emotion, and stronger emotional intensity for both involuntary memories and future thoughts compared with individuals without schizotypal features. Further analyses in individuals with schizotypal personality features showed that the frequencies of both involuntary memories and future thoughts were significantly correlated with positive schizotypal traits. These results have potential theoretical and clinical implications for a comprehensive understanding of involuntary MTT among individuals with schizotypal personality features.