Effect of high-endurance exercise intervention on sleep-dependent procedural memory consolidation in individuals with schizophrenia: a randomized controlled trial

BACKGROUND

Little is known about the effects of physical exercise on sleep-dependent consolidation of procedural memory in individuals with schizophrenia. We conducted a randomized controlled trial (RCT) to assess the effectiveness of physical exercise in improving this cognitive function in schizophrenia.

METHODS

A three-arm parallel open-labeled RCT took place in a university hospital. Participants were randomized and allocated into either the high-intensity-interval-training group (HIIT), aerobic-endurance exercise group (AE), or psychoeducation group for 12 weeks, with three sessions per week. Seventy-nine individuals with schizophrenia spectrum disorder were contacted and screened for their eligibility. A total of 51 were successfully recruited in the study. The primary outcome was sleep-dependent procedural memory consolidation performance as measured by the finger-tapping motor sequence task (MST). Assessments were conducted during baseline and follow-up on week 12.

RESULTS

The MST performance scored significantly higher in the HIIT (n = 17) compared to the psychoeducation group (n = 18) after the week 12 intervention (p < 0.001). The performance differences between the AE (n = 16) and the psychoeducation (p = 0.057), and between the AE and the HIIT (p = 0.999) were not significant. Yet, both HIIT (p < 0.0001) and AE (p < 0.05) showed significant within-group post-intervention improvement.

CONCLUSIONS

Our results show that HIIT and AE were effective at reverting the defective sleep-dependent procedural memory consolidation in individuals with schizophrenia. Moreover, HIIT had a more distinctive effect compared to the control group. These findings suggest that HIIT may be a more effective treatment to improve sleep-dependent memory functions in individuals with schizophrenia than AE alone.

Working memory deterioration as an early warning sign for relapse in remitted psychosis: A one-year naturalistic follow-up study

BACKGROUND

Relapse prevention is an important goal in the clinical management of psychosis. Cognitive deficits/deterioration can provide useful insights for monitoring relapse in psychosis patients.

METHODS

This was a prospective, naturalistic 1-year follow-up study involving 110 psychosis patients with full clinical remission. Relapse, defined as the recurrence of psychotic symptoms, was monitored monthly along with digital tracking of verbal and visual working memory using a mobile app developed for this study. Cognitive deterioration was defined as worsening performance over 2 months prior to relapse or study termination, whichever was earlier. Other clinical, cognitive, functioning, and psychosocial variables were also collected.

RESULTS

At 1 year, 18 (16.36%) patients relapsed, of which 6 (33.33%) required hospitalization. Relapse was predicted by verbal working memory deterioration 2 months prior to relapse (p = 0.029), worse medication adherence (p = 0.018), and less resilience (p = 0.014).

CONCLUSIONS

Verbal working memory deterioration is a novel early sign of relapse. It is a clearly defined, objectively measurable, and reproducible marker that can help clinicians and healthcare workers identify patients at risk of relapse and make decisions about maintenance therapy. Moreover, digital monitoring is a viable tool in the management of relapse.

Abnormal cognitive effort allocation and its association with amotivation in first-episode psychosis

BACKGROUND

Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP).

METHOD

Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants' willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored.

RESULTS

Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits.

CONCLUSION

This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP.

The role of symptoms and insight in mediating cognition and functioning in first episode psychosis

INTRODUCTION

Achieving functional recovery in patients with psychosis is a challenge in clinical practice. Investigating the complex interplay between cognition, symptoms, insight and functional outcome in first episode psychosis will be crucial to understanding the factors leading to better functioning.

METHODS

In this 12-month prospective follow-up study, we investigated how cognition, clinical symptoms, and insight into illness affected overall functioning in 160 patients with first episode psychosis recruited from the Early Assessment Service for Young People with Psychosis (EASY) in Hong Kong from July 1, 2014 to June 30, 2016. Cognition was assessed at baseline while symptoms, insight, and functioning were assessed at 12-month follow-up. Structural equation modelling was used to examine the direct and indirect relationships between functioning and other latent constructs.

RESULTS

Symptoms (negative symptoms and general psychopathology) and insight were shown to be significant mediators between cognition and functioning. The significant direct relationship between cognition and functioning (β = 0.387; p < 0.001) became insignificant (β = 0.079; p = 0.578) after including symptoms and insight in the model. Symptoms and insight were significantly associated with cognition (symptoms, β = -0.469; p < 0.001; insight, β = -0.372; p < 0.001) and predicted functioning (symptoms, β = -0.558; p < 0.001; insight, β = -0.264; p < 0.01).

CONCLUSION

Symptoms and insight mediated the effects of cognition on functioning. Interventions for improving functioning in patients with first episode psychosis should target not only cognition but also symptoms and insight.

Presenile dementia: a case of Hashimoto's encephalopathy

Hashimoto's encephalopathy may present with a variety of neurological symptoms and signs, including myoclonus, epileptic seizures, disturbance of consciousness, psychosis, ataxia, and presenile dementia. This report is of a 57-year-old woman with a history of thyroid disease who was investigated for generalised seizures, rapid decline in cognitive function, increasing dependency, and gradual change in personality. High thyroid autoantibody titres confirmed the diagnosis of Hashimoto's encephalopathy and her symptoms improved with treatment with prednisolone. The differential diagnosis of presenile dementia, aetiology and pathogenesis of Hashimoto's encephalomyelitis, and treatment options are discussed. Hashimoto's encephalomyelitis should be considered in the differential diagnosis of presenile dementia, particularly in patients with a history of thyroid disease.

Psychosis related to the use of sibutramine disguised as over-the-counter herbal weight loss remedies: a report of two patients

Two women presented independently with a clinical picture of mania-like psychosis after taking over-the-counter herbal slimming pills. Subsequent toxicology investigation found sibutramine in the samples of both patients. Sibutramine is an effective pharmacological treatment for obesity with a relatively favourable side-effect profile. However, neuropsychiatric side-effects of sibutramine have emerged with increasing use of the medication. Sibutramine may be associated with the development of psychotic symptoms in susceptible individuals. Further studies should aim at establishing any causal relationship between sibutramine and psychosis. There also seems to be an emerging trend of adulteration of over-the-counter slimming products with pharmaceutical analogues in Hong Kong. Physicians should be vigilant to the possibility of non-prescribed drug use when patients present with suspicious symptoms while using herbal remedies.