Prospective memory in first-degree relatives of patients with schizophrenia

Effects of bilateral repetitive transcranial magnetic stimulation on prospective memory in patients with schizophrenia: A double-blind randomized controlled clinical trial

AIMS

To investigate effects of repetitive transcranial magnetic stimulation (rTMS) on the prospective memory (PM) in patients with schizophrenia (SCZ).

METHODS

Fifty of 71 patients completed this double-blind placebo-controlled randomized trial and compared with 18 healthy controls' (HCs) PM outcomes. Bilateral 20 Hz rTMS to the dorsolateral prefrontal cortex at 90% RMT administered 5 weekdays for 4 weeks for a total of 20 treatments. The Positive and Negative Symptom Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), and PM test were assessed before and after treatment.

RESULTS

Both Event-based PM (EBPM) and Time-based PM (TBPM) scores at baseline were significantly lower in patients with SCZ than that in HCs. After rTMS treatments, the scores of EBPM in patients with SCZ was significantly improved and had no differences from that in HCs, while the scores of TBPM did not improved. The negative symptom scores on PANSS and the scores of almost all subscales and total scores of SANS were significantly improved in both groups.

CONCLUSIONS

Our findings indicated that bilateral high-frequency rTMS treatment can alleviate EBPM but not TBPM in patients with SCZ, as well as improve the negative symptoms.

SIGNIFICANCE

Our results provide one therapeutic option for PM in patients with SCZ.

Nonverbal communication remains untouched: No beneficial effect of symptomatic improvement on poor gesture performance in schizophrenia

BACKGROUND

Gestures are an important part of communication. Patients with schizophrenia present gesture deficits that tend to deteriorate in the course of the disease and hamper functional outcome. This gesture deficit has been associated with motor abnormalities, cognitive impairment, and psychotic symptoms. Unaffected, first-degree relatives of schizophrenia patients share some subclinical motor and cognitive abnormalities. We aimed to investigate, whether gesture performance changes with symptomatic improvement in patients, and to test the longitudinal performance in unaffected, first-degree relatives.

METHODS

In this study, we measured gesture performance using a validated test in 33 patients, 29 first-degree relatives and 38 healthy controls. Measurements were completed shortly after admission and before discharge in patients. Performance was rated blindly by experts using video recordings of the gesture task. Additionally, we evaluated cognitive function and psychotic symptoms at both visits.

RESULTS

Gesture performance was poorer in relatives compared to controls and poorer in patients compared to both relatives and controls. Patients showed an improvement in psychopathology but a significant decrease in gesture performance at follow-up, while performance in the other groups remained stable. Proportional change of gesture performance correlated with change of cognitive function in patients, whereas there were no correlations with change of cognitive function in the other groups.

CONCLUSION

While symptom severity was reduced, the gesture deficit further deteriorated in schizophrenia. The finding argues for distinct processes contributing to poor nonverbal communication skills in patients, requiring novel alternative treatment efforts.

Neurocan genome-wide psychiatric risk variant affects explicit memory performance and hippocampal function in healthy humans

Alterations of the brain extracellular matrix (ECM) can perturb the structure and function of brain networks like the hippocampus, a key region in human memory that is commonly affected in psychiatric disorders. Here, we investigated the potential effects of a genome-wide psychiatric risk variant in the NCAN gene encoding the ECM proteoglycan neurocan (rs1064395) on memory performance, hippocampal function and cortical morphology in young, healthy volunteers. We assessed verbal memory performance in two cohorts (N = 572, 302) and found reduced recall performance in risk allele (A) carriers across both cohorts. In 117 participants, we performed functional magnetic resonance imaging using a novelty-encoding task with visual scenes. Risk allele carriers showed higher false alarm rates during recognition, accompanied by inefficiently increased left hippocampal activation. To assess effects of rs1064395 on brain morphology, we performed voxel-based morphometry in 420 participants from four independent cohorts and found lower grey matter density in the ventrolateral and rostral prefrontal cortex of risk allele carriers. In silico eQTL analysis revealed that rs1064395 SNP is linked not only to increased prefrontal expression of the NCAN gene itself, but also of the neighbouring HAPLN4 gene, suggesting a more complex effect of the SNP on ECM composition. Our results suggest that the NCAN rs1064395 A allele is associated with lower hippocampus-dependent memory function, variation of prefrontal cortex structure and ECM composition. Considering the well-documented hippocampal and prefrontal dysfunction in bipolar disorder and schizophrenia, our results may reflect an intermediate phenotype by which NCAN rs1064395 contributes to disease risk.

Promoting insight into delusions: Issues and challenges in therapy

During recent years, the role of non-pharmacological interventions in the management of psychotic symptoms, including delusions, has received increased recognition. However, a few factors such as the client's cognitive impairments and poor insight into the illness may create challenges for the therapist in conducting these interventions. Present paper discusses some of these issues and the steps a therapist can take to deal with them.

Prospective memory in schizophrenia: A meta-analysis of comparative studies

BACKGROUND

Impairment of prospective memory (PM) in schizophrenia has gained increasing attention. This meta-analysis systematically examined PM impairment in schizophrenia.

METHODS

Both English (PubMed, PsycINFO, EMBASE, and Cochrane Library) and Chinese (WanFang, Chinese Biomedical and China Journal Net databases) databases were systematically searched from their inception until August 14, 2017. Case-control studies of PM in schizophrenia were included. Standardized mean differences (SMDs) and their 95% confidence interval (CI) were calculated using the random-effects model.

RESULTS

Twenty-nine case-control studies (n = 2492) were included in the analyses. The overall and three subtypes of PM were compared between patients with schizophrenia (n = 1284) and healthy controls (n = 1208). Compared to healthy controls, patients performed significantly poorer in overall (SMD = -1.125), time-based (SMD = -1.155), event-based (SMD = -1.068), and activity-based PM (SMD = -0.563). Subgroup analyses revealed significant differences between older and younger patients (SMD = -1.398 vs. -0.763), higher male predominance and no sex predominance (SMD = -1.679 vs. -0.800), lower and higher education level (SMD = -1.373 vs.-0.637), chronic and first-episode patients (SMD = -1.237 vs. -0.641) and between eco-valid and dual-task laboratory measurements (SMD = -1.542 vs. -0.725) regarding overall PM. Meta-regression analysis showed that higher negative symptom score was significantly associated with more severe overall PM impairment in patients (P = 0.022).

CONCLUSIONS

In this meta-analysis the overall PM and all its subtypes, particularly the time-based PM, were significantly impaired in schizophrenia.

Prospective memory in clinical populations

OBJECTIVE

Prospective memory (PM) has emerged as a form of episodic memory that is frequently impaired in a variety of clinical populations. Neuropsychologists who routinely evaluate these populations are often unaware of the possibility of PM deficits or the impact these deficits may have on everyday functioning. The objective of this special issue is to provide an overview of the nature of prospective deficits in a range of clinical populations, to discuss neuropsychological assessment techniques, and to critically evaluate management strategies.

METHOD

We solicited papers from established researchers and issued a general call for papers for the special issue on PM in clinical populations.

RESULTS

We received submissions from the nine authors that we solicited. These submissions range from developmental disorders, including autism, attention deficit hyperactivity disorder, and dyslexia; to disorders of adulthood, such as schizophrenia, HIV, brain injury, and multiple sclerosis; and finally disorders that tend to occur at older ages, such as Parkinson's disease and mild cognitive impairment. In addition, we have included four original research articles that provide novel data on other populations. These are children and adolescents with 22q11.2 deletion syndrome, first-degree relatives of people with schizophrenia, individuals with mild brain injury, and individuals with idiopathic REM sleep behavioral disorder.

CONCLUSIONS

The issue highlights the need for clinical neuropsychologists to be aware of the possible existence of deficits in PM in a variety of clinical populations and the importance of both assessment and management strategies to reduce the impact on daily life.

Prospective memory in non-psychotic first-degree relatives of patients with schizophrenia: a meta-analysis

Prospective memory (PM) could be impaired in the non-psychotic first-degree relatives of patients with schizophrenia. This meta-analysis systematically examined the PM of non-psychotic first-degree relatives of patients with schizophrenia. Both Chinese and English databases were systematically searched for articles from the inception of the databases through November 13, 2018. Case-control studies of PM in non-psychotic first-degree relatives of patients with schizophrenia were included in the analyses. Confidence intervals (CIs) and standardized mean differences (SMDs) were calculated utilizing the random effects model. Four studies (n=268) that compared PM performance between non-psychotic first-degree relatives of patients with schizophrenia (n=136) and healthy controls (n=132) were included. Three studies were rated as "high quality", while the quality of evidence of the three outcomes included in this meta-analysis was moderate. Compared with the healthy controls, the non-psychotic first-degree relatives of patients with schizophrenia showed impairments in overall PM (two studies, n=127; SMD: -0.46; 95% CI=-0.82, -0.11, P=0.01; I=0%), event-based PM (EBPM) (four studies, n=268; SMD: -0.56; 95% CI=-0.80, -0.31, P<0.00001; I=0%), and time-based PM (TBPM) (four studies, n=268; SMD: -0.66; 95% CI=-0.90, -0.41, P<0.00001; I=0%). This meta-analysis demonstrated that the overall PM, EBPM, and TBPM might be impaired in the non-psychotic first-degree relatives of patients with schizophrenia.