Spurious Autobiographical Memory of Psychosis: A Mechanistic Hypothesis for the Resolution, Persistence, and Recurrence of Positive Symptoms in Psychotic Disorders.

Psychotic disorders are complex disorders with multiple etiologies. While increased dopamine synthesis capacity has been proposed to underlie psychotic episodes, dopamine-independent processes are also involved (less responsive to dopamine receptor-blocking medications). The underlying mechanism(s) of the reduction in antipsychotic responsiveness over time, especially after repeated relapses, remain unclear. Despite the consistent evidence of dopamine overactivity and hippocampal volume loss in schizophrenia, few accounts have been provided based on the interactive effect of dopamine on hippocampal synapse plasticity mediating autobiographical memory processes. The present hypothesis builds upon previous works showing the potential effects of dopamine overactivity on hippocampal-mediated neuroplasticity underlying autobiographical memory, alongside known patterns of autobiographical memory dysfunction in psychosis. We propose that spurious autobiographical memory of psychosis (SAMP) produced during active psychosis may be a key mechanism mediating relapses and treatment non-responsiveness. In a hyperdopaminergic state, SAMP is expected to be generated at an increased rate during active psychosis. Similar to other memories, it will undergo assimilation, accommodation, and extinction processes. However, if SAMP fails to integrate with existing memory, a discontinuity in autobiographical memory may result. Inadequate exposure to normalizing experiences and hyposalience due to overmedication or negative symptoms may also impede the resolution of SAMP. Residual SAMP is hypothesized to increase the propensity for relapse and treatment non-responsiveness. Based on recent findings on the role of dopamine in facilitating hippocampal synapse plasticity and autobiographical memory formation, the SAMP hypothesis is consistent with clinical observations of DUP effects, including the repetition of contents in psychotic relapses as well as the emergence of treatment non-responsiveness after repeated relapses. Clinical implications of the hypothesis highlight the importance of minimizing active psychosis, integrating psychosis memory, avoiding over-medication, and fostering normalizing experiences.

Stability of Montreal Cognitive Assessment in Individuals with Mild Cognitive Impairment: Potential Influence of Practice Effect.

BACKGROUND: The Montreal Cognitive Assessment (MoCA) is a standard test for screening and monitoring cognitive functions. OBJECTIVE: This study explored the two-year changes in MoCA scores in older adults. METHODS: Fifty-seven participants with mild cognitive impairment (MCI) and 87 participants with normal cognition completed the baseline and two-year follow-up assessments. Apart from MoCA, tests on visuospatial judgment, memory, and motor-related executive function were administered. RESULTS: The results identified three MCI subgroups based on the differential changes in MoCA scores. They were the consistently low, consistently high, and low-to-high between-time performances. These heterogeneous test performances are on contrary to the significant deteriorations in executive function and finger dexterity across all subgroups. Repeated exposure to MoCA tests during the follow-up period was found to be a plausible indicator of the MCI subgroup categorization. CONCLUSION: Findings raise concerns over adopting brief clinical instrument for repeated testing, such as MoCA, for monitoring MCI conditions among older adults.