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Fulltext A review of autobiographical memory studies on patients with schizophrenia spectrum disorders

Zhang Y, Kuhn SK, Jobson L, Haque S

BMC Psychiatry, 2019 11 14;19(1):361.
PMID: 31727046 DOI: 10.1186/s12888-019-2346-6

BACKGROUND: Patients suffering from schizophrenia spectrum disorders demonstrate various cognitive deficiencies, the most pertinent one being impairment in autobiographical memory. This paper reviews quantitative research investigating deficits in the content, and characteristics, of autobiographical memories in individuals with schizophrenia. It also examines if the method used to activate autobiographical memories influenced the results and which theoretical accounts were proposed to explain the defective recall of autobiographical memories in patients with schizophrenia.
METHODS: PsycINFO, Web of Science, and PubMed databases were searched for articles published between January 1998 and December 2018. Fifty-seven studies met the inclusion criteria. All studies implemented the generative retrieval strategy by inducing memories through cue words or pictures, the life-stage method, or open-ended retrieval method. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement guidelines were followed for this review.
RESULTS: Most studies reported that patients with schizophrenia retrieve less specific autobiographical memories when compared to a healthy control group, while only three studies indicated that both groups performed similarly on memory specificity. Patients with schizophrenia also exhibited earlier reminiscence bumps than those for healthy controls. The relationship between comorbid depression and autobiographical memory specificity appeared to be independent because patients' memory specificity improved through intervention, but their level of depression remained unchanged. The U-shaped retrieval pattern for memory specificity was not consistent. Both the connection between the history of attempted suicide and autobiographical memory specificity, and the relationship between psychotic symptoms and autobiographical memory specificity, remain inconclusive. Patients' memory specificity and coherence improved through cognitive training.
CONCLUSIONS: The overgeneral recall of autobiographical memory by patients with schizophrenia could be attributed to working memory, the disturbing concept of self, and the cuing method implemented. The earlier reminiscence bump for patients with schizophrenia may be explained by the premature closure of the identity formation process due to the emergence of psychotic symptoms during early adulthood. Protocol developed for this review was registered in PROSPERO (registration no: CRD42017062643).

Matched MeSH terms: Memory Disorders/psychology*
Subjective memory and concentration deficits in medication-free, non-elderly Asians with major depressive disorder: prevalence and their correlates

Srisurapanont M, Bautista D, Chen CH, Wang G, Udomratn P, Eurviriyanukul K

J Affect Disord, 2015 Jan 15;171:105-10.
PMID: 25303026 DOI: 10.1016/j.jad.2014.09.007

BACKGROUND: Subjective cognitive impairment (SCI) in major depressive disorder (MDD) is prevalent and correlated with disability. This study aimed to examine the prevalence rates and correlates of subjective memory deficit (SMD) and subjective concentration deficit (SCD) in medication-free, non-elderly Asians with MDD.
METHODS: The SMD and SCD were assessed by using two items of the Symptom Checklist-90-Revised (SCL-90-R). Other measurements of interest included the Montgomery-Asberg Depression Rating Scale (MADRS), the Fatigue Severity Scale (FSS), the Sheehan Disability Scale (SDS), and the Short Form Health Survey (SF-36). Adjusted odds ratios with 95% confidence intervals were calculated.
RESULTS: Of 515 participants from China, Korea, Malaysia, Singapore, Taiwan, and Thailand, 347 (67.4%) and 377 (73.2%) had SMD and SCD, respectively. In total, 420 participants (81.6%) had SMD alone, SCD alone, and both deficits. Severe depression and poor mental health were significant correlates of SMD. Severe depression, clinically significant disability, poor physical health, and poor mental health were significantly independent correlates of SCD. Compared with young adults (18-34 years), older adults aged 50-65 years had a significantly lower risk of SCD (OR=.33, 95% CI: .19-.57).
LIMITATIONS: Only two SCL-90-R items were used to assess the SMD and SCD. The exclusion of MDD patients treated with psychotropic medications eliminated many patients commonly seen in typical clinic settings.
CONCLUSION: SMD and SCD are prevalent in medication-free, non-elderly Asians with MDD. Both deficits are correlated with depression and mental health status. The independent correlation between SCD and disability underscores the crucial role of SCI in MDD.
KEYWORDS: Asian; Cognitive impairment; Depressive disorders; SCL-90-R; Subjective

Matched MeSH terms: Memory Disorders/psychology
Fulltext Phencyclidine dose optimisation for induction of spatial learning and memory deficits related to schizophrenia in C57BL/6 mice

Zain MA, Rouhollahi E, Pandy V, Mani V, Majeed ABA, Wong WF, et al.

Exp Anim, 2018 Nov 01;67(4):421-429.
PMID: 29731492 DOI: 10.1538/expanim.18-0006

Phencyclidine (PCP) has been used to model cognitive deficits related to schizophrenia in rats and mice. However, the model in mice is not consistent in terms of the PCP effective dose reported. Furthermore, most of the previous studies in mice excluded the presence of drug washout period in the regime. Thus, we aimed to optimize the dose of PCP in producing robust cognitive deficits by implementing it in a PCP regime which incorporates a drug washout period. The regimen used was 7 days' daily injection of PCP or saline for treatment and vehicle groups, respectively; followed by 24 h drug washout period. After the washout period, the test mice were tested in water maze (5 days of acquisition + 1 day of probe trial) for assessment of spatial learning and memory. Initially, we investigated the effect of PCP at 2mg/kg, however, no apparent impairment in spatial learning and memory was observed. Subsequently, we examined the effect of higher doses of PCP at 5, 10 and 20 mg/kg. We found that the PCP at 10 mg/kg produced a significant increase in "latency to reach the platform" during the acquisition days and a significant increase in "latency of first entry to previous platform" during the probe day. There was no significant change observed in "swim speed" during the test days. Thus, we concluded that PCP at 10 mg/kg produced robust deficits in spatial learning and memory without being confounded by motor disturbances.

Matched MeSH terms: Memory Disorders/psychology*
Prevalence and factors of verbal learning and memory dysfunction in patients with epilepsy - A single centre study

Subramaniam SR, Khoo CS, Raymond AA, Che Din N, Syed Zakaria SZ, Tan HJ

J Clin Neurosci, 2020 Mar;73:31-36.
PMID: 32094071 DOI: 10.1016/j.jocn.2020.02.003

The objective of this study is to determine prevalence and factors leading to verbal learning and memory dysfunction among patients with epilepsy. A total of 211 subjects were recruited. Their verbal memory was assessed by Rey's Auditory Verbal Learning Test (RAVLT). This test was further subdivided into four major spheres for analysis, namely the verbal learning, interference list, immediate memory and delayed memory. All data collected were analyzed using Statistical Package for Social Sciences. Among the 211 patients, 55% (n = 116) had focal seizures and the remaining 45% (n = 95) had generalized seizures. Prevalence of verbal learning and memory impairment was high at 39.97% overall, and found most commonly in patients with focal impaired awareness seizures. Verbal learning and immediate memory dysfunction were significantly lower in focal impaired awareness group compared to others. Age more than 50 years, exposure to three or more antiepileptic drugs and use of carbamazepine more than 1000 mg a day were the predictors in poor verbal memory outcome. No statistical difference was observed in the mean RAVLT scores among the gender and hand dominance groups. Between patients with and without electroencephalogram changes as well as brain magnetic resonance imaging changes, the mean RAVLT scores showed no statistically significant difference. Verbal learning and memory impairment is prevalent among the epilepsy patients. The consequences of the memory impairment can be as debilitating as the seizure control. RAVLT is a reliable and practical test in the clinical setting.

Matched MeSH terms: Memory Disorders/psychology
Deoxyelephantopin ameliorates lipopolysaccharides (LPS)-induced memory impairments in rats: Evidence for its anti-neuroinflammatory properties

Andy SN, Pandy V, Alias Z, Kadir HA

Life Sci, 2018 Aug 01;206:45-60.
PMID: 29792878 DOI: 10.1016/j.lfs.2018.05.035

AIM: Neuroinflammation is a critical pathogenic mechanism of most neurodegenerative disorders especially, Alzheimer's disease (AD). Lipopolysaccharides (LPS) are known to induce neuroinflammation which is evident from significant upsurge of pro-inflammatory mediators in in vitro BV-2 microglial cells and in vivo animal models. In present study, we investigated anti-neuroinflammatory properties of deoxyelephantopin (DET) isolated from Elephantopus scaber in LPS-induced neuroinflammatory rat model.
MATERIALS AND METHODS: In this study, DET (0.625. 1.25 and 2.5 mg/kg, i.p.) was administered in rats for 21 days and those animals were challenged with single injection of LPS (250 μg/kg, i.p.) for 7 days. Cognitive and behavioral assessment was carried out for 7 days followed by molecular assessment on brain hippocampus. Statistical significance was analyzed with one-way analysis of variance followed by Dunnett's test to compare the treatment groups with the control group.
KEY FINDINGS: DET ameliorated LPS-induced neuroinflammation by suppressing major pro-inflammatory mediators such as iNOS and COX-2. Furthermore, DET enhanced the anti-inflammatory cytokines and concomitantly suppressed the pro-inflammatory cytokines and chemokine production. DET treatment also reversed LPS-induced behavioral and memory deficits and attenuated LPS-induced elevation of the expression of AD markers. DET improved synaptic-functionality via enhancing the activity of pre- and post-synaptic markers, like PSD-95 and SYP. DET also prevented LPS-induced apoptotic neurodegeneration via inhibition of PARP-1, caspase-3 and cleaved caspase-3.
SIGNIFICANCE: Overall, our studies suggest DET can prevent neuroinflammation-associated memory impairment and neurodegeneration and it could be developed as a therapeutic agent for the treatment of neuroinflammation-mediated and neurodegenerative disorders, such as AD.

Matched MeSH terms: Memory Disorders/psychology