Are cardiometabolic and endocrine abnormalities linked to sleep difficulties in schizophrenia? A hypothesis driven review

A mixed methods expert opinion study on the optimal content and format for an occupational therapy intervention to improve sleep in schizophrenia spectrum disorders

Introduction

People with schizophrenia spectrum disorder diagnoses commonly have poor sleep, which predicts various negative outcomes. The problems are diverse, including substantial circadian dysregulation, sleep-wake timing issues, hypersomnia (excessive sleep), and more classic insomnia.

Methods

This paper reports on a mixed methods expert opinion study based on the principles of Delphi methodology. The study examines and explores opinion on the optimal contents and format for an occupational therapy intervention to improve poor sleep in this population. Views of clinical and academic topic experts (n = 56), were elicited, examined and explored in three rounds, views from previous rounds being presented back to participants in subsequent rounds. Participants with relevant personal experience (n = 26) then rated and commented on suggestions, with a focus on acceptability. Descriptive statistics and graphs of ratings were triangulated with qualitative content analysis of free-text.

Results

Participants emphasised the central importance of intervention personalisation, although the manner and extent of personalisation suggested varied. Many components and domains were acknowledged as important, with the challenge being how to keep such an intervention simple, brief, and feasible for end-users, for sustainable implementation. The strongest consensus was to address evening routine, daytime activity, and environmental interventions. Relaxation, mindfulness, thermoregulation, sensory factors, and cognitive or psychological approaches were rated as less important. There was disagreement on whether to include time in bed restriction, and how to address napping, as well as how far to address medication timing. Clinicians and researchers advocated some version of stimulus control, but participants with personal experience reported low levels of acceptability for this, describing entirely negative experiences using ‘the 15-minute rule’ (part of stimulus control).

Conclusion

These results are informative for clinicians treating sleep problems in people with schizophrenia and related conditions, as well as for decision makers considering the potential contribution of the profession of occupational therapy toward sleep treatment.

Association between obesity and white matter microstructure impairments in patients with schizophrenia: A whole-brain magnetic resonance imaging study

AIM

We aimed to examine the possible association of obesity (body mass index [BMI] ≥ 30) with symptoms, psychotropic medication, and whole-brain structure in patients with schizophrenia.

METHODS

Participants were 65 patients diagnosed with schizophrenia (mean age: 37.2 ± 11.3 years, 32 females). All participants were Japanese and right-handed. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) and Pittsburgh Sleep Quality Index (PSQI). Voxel based morphometry (VBM) and diffusion tensor imaging (DTI) were performed to analyze the association of obesity with gray and white matter structures, respectively.

RESULTS

There was no significant difference in PANSS scores between obese and non-obese patients, while the PSQI score was significantly higher in the former than in the latter (p < 0.05). The daily dose of typical antipsychotics was significantly higher in obese patients than in non-obese patients (p < 0.001). In VBM, there was no significant difference in gray matter volume between obese and non-obese patients. In DTI, fractional anisotropy values in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, and posterior thalamic radiations were significantly lower in obese patients than in non-obese patients (corrected p < 0.05). Axial diffusivity was significantly lower while radial and mean diffusivities values were significantly higher in obese patients than in non-obese patients (corrected p < 0.05) in similar but more restricted brain regions.

CONCLUSION

Our results suggest that obesity is related to sleep disturbances, daily dose of typical antipsychotics, and regional white matter microstructure impairments in patients with schizophrenia.

Effect of Haloperidol and Risperidone on Serum Melatonin and GAP-43 in Patients with Schizophrenia: A Prospective Cohort Study

OBJECTIVE

Serum melatonin, a biomarker of circadian rhythm, can upregulate Growth-associated protein 43 (GAP-43) which is involved in neural regeneration and plasticity. The present study was conducted to investigate the adequacy of the first-line antipsychotic drugs to improve sleep and circadian rhythm disruptions by assessing the effect of haloperidol and risperidone on serum melatonin and GAP-43 in schizophrenia.

METHODS

In this cohort study, 100 schizophrenic patients were recruited, and clinical evaluations were done using the Positive and Negative Syndrome Scale (PANSS) and the Pittsburgh sleep quality index (PSQI). The patients with predominantly positive symptoms taking haloperidol (Group I) and patients with predominantly negative symptoms taking risperidone (Group II) were admitted and serum melatonin, arylalkylamine N-acetyltransferase, GAP-43 and urinary melatonin were estimated. After 8 weeks, all clinical and biochemical parameters were repeated.

RESULTS

Serum melatonin (2:00 hours) was significantly decreased in both haloperidol (2.42; 95% confidence interval [95% CI]: 0.67-4.17; p = 0.008) and risperidone group (3.40; 95% CI: 0.54-6.25; p = 0.021). Urinary melatonin was significantly decreased in both haloperidol (p = 0.005) and risperidone group (p = 0.014). PSQI score was significantly increased in both haloperidol (p = 0.001) and risperidone group (p = 0.003). Serum GAP-43 was significantly decreased in both haloperidol and risperidone group (p < 0.001). PANSS decreased significantly in both the groups and there was a significant negative correlation between serum melatonin at 2:00 hours and PANSS (r = -0.5) at baseline.

CONCLUSION

Monotherapy with haloperidol and risperidone can achieve symptomatic improvement but cannot improve sleep and circadian rhythm disturbances in schizophrenia.

Evidence for an association of serum melatonin concentrations with recognition and circadian preferences in patients with schizophrenia

Melatonin, a neuro-differentiation factor, may play a role in the neurodevelopmental origins of schizophrenia. Cognitive impairment and decreased melatonin are reported in schizophrenia; however, the relationship between them remains unclear. We hypothesised that patients with schizophrenia would have lower concentrations of circulating melatonin than healthy controls and that melatonin levels would be associated with cognitive impairment. This study included 47 patients with schizophrenia and 40 healthy controls (HC). Serum melatonin concentrations were measured using the enzyme-linked immunosorbent assay. Positive and Negative Syndrome Scales (PANSS), The Morningness-Eveningness Questionnaire (MEQ), Pittsburgh Sleep Quality Index (PSQI), the Stroop and Oktem verbal memory processes (VMPT) tests were applied. Patients with schizophrenia had lower levels of melatonin compared to the HC group (p = 0.016), also after controlling for age, sex, and body mass index (BMI) (p = 0.024). In patients with schizophrenia, melatonin concentrations were associated with higher BMI (rho = 0.34, p = 0.01) and lower MEQ score (rho = -0.29, p = 0.035). The patient sample was split into low and high melatonin categories by using the median melatonin concentration in HC as the cut-off. Patients in the low melatonin group had poorer performance in VMPT-Recognition (p = 0.026) and Stroop-Colour Error (p = 0.032). Notwithstanding its limitations, the findings of this exploratory study suggest that decreased serum melatonin concentrations observed in schizophrenia might also be associated with cognitive impairment and circadian preferences. Future studies are required to investigate the role of melatonergic pathways in patients with schizophrenia.