Study of the different sleep disturbances during the prodromal phase of depression and mania in bipolar disorders

BACKGROUND

One of the challenges in bipolar disorder (BD) lies in early detection of the illness and its recurrences, to improve prognosis. Sleep disturbances (SD) have been proposed as reliable predictive markers of conversion. While preliminary studies have explored the relationship between SD and the onset of mood episodes, the results remain heterogeneous and a few have specifically examined patients' perception of prodromal symptoms and their progression until the episode occurs. Identifying prodromes represents a crucial clinical challenge, as it enables early intervention, thereby reducing the severity of BD. Therefore, the objective of this study is to better characterize and evaluate the progressive nature of SD as prodromal symptoms of mood episodes, and patients' perception of it.

METHODS

Patients diagnosed with BD, either hospitalized or seeking treatment for a (hypo)manic or depressive episode benefited from standardized questionnaires, structured interviews, and self-report questionnaires to evaluate SD prior to the current episode, as well as sociodemographic and clinical information.

RESULTS

Out of the 41 patients included, 59% spontaneously reported SD prior to the episode, appearing 90 days before depression and 35 days before mania (pre-indexed/spontaneous reports: 51.22% insomnia complaints, 4.88% hypersomnolence complaints, 7.32% parasomnias, 2.44% sleep movements). After inquiry about specific SD, the percentage of patients reporting prodromal SD increased significantly to 83%, appearing 210 days before depression and 112.5 days before mania (post-indexed reports: 75.61% presented with insomnia complaints appearing 150 days before depression and 20 days before mania, 46.34% had hypersomnolence complaints appearing 60 days before depression, 43.9% had parasomnias appearing 210 days before depression and 22.5 days before mania, 36.59% had sleep movements appearing 120 days before depression and 150 days before mania). Of note, bruxism appeared in 35% of patients before mania, and restless legs syndrome in 20% of patients before depression.

CONCLUSION

This study highlights the very high prevalence of SD prior to a mood episode in patients with BD with differences between depressive and manic episodes. The more systematic screening of sleep alterations of the prodromal phase improved the recognition and characterization of different symptoms onset by patients. This underscores the need for precise questioning regarding sleep patterns in patients, to better identify the moment of transition toward a mood episode, referred to as "Chronos syndrome". The study emphasizes the importance of educating patients about the disorder and its sleep prodromal symptoms to facilitate early intervention and prevent recurrences.

Comparative study of sleep and circadian rhythms in patients presenting unipolar or bipolar major depressive episodes

Currently, there is a major challenge in distinguishing between unipolar and bipolar major depressive episode. A significant body of research has been dedicated to identifying biomarkers that can aid in this differentiation due to its crucial implications, particularly for therapeutic and prognostic purposes. Among the biomarkers of interest, markers related to sleep and circadian rhythms show promise and could potentially aid in making this distinction. Nevertheless, no study has simultaneously examined sleep-wake disorders, circadian rhythms, and seasonal patterns using both subjective and objective measures. This study aims to characterize and compare the sleep-wake and rhythm disorders including patients with unipolar major depressive episode (n = 72) and with bipolar major depressive episode (n = 43) using both subjective markers (using self-report questionnaires and sleep complaints) and objective markers (using actigraphy). Patients with unipolar major depressive episode seem to experience significantly poorer quality of sleep, more symptoms of insomnia and lower sleep efficiency compared to patients with bipolar major depressive episode. On the other hand, patients with bipolar major depressive episode exhibit significantly more symptoms of motor retardation and hypersomnia compared to patients with unipolar disorder. These results hold significant implications for identifying individuals with unipolar major depressive episode or bipolar major depressive episode using sleep and circadian markers, and for developing recommended and personalized therapeutic strategies.

Skin conductance while facing emotional pictures at day 7 helps predicting antidepressant response at three months in patients with a major depressive episode

There are currently no reliable biological markers to identify antidepressant responders in patients suffering from major depressive disorder. In this longitudinal pilot study, we measured skin conductance response (SCR) to assess patients' emotional reactivity after antidepressant treatment initiation. Fifty-four adult patients with a major depressive episode were recruited and followed up for 3 months. After one day of antidepressant treatment (D1) and then at day 7 (D7), emotional stimuli were presented on a computer screen while SCR and subjective emotional response were recorded. Three months later, we used Montgomery and Åsberg Depression Rating Scale (MADRS) to screen patients for treatment response, and distinguished responders (N = 28) from non-responders (N = 15). While SCR at D1 did not differ between responders and non-responders, SCR at D7 was higher in responders for both positive, negative and neutral stimuli. Skin conductance rates at D7 had a relatively poor negative predictive value (38%) but a strong positive predictive value (95%). Further studies are needed to replicate in a larger sample, and validate, these preliminary results which suggest that electrodermal activity after treatment initiation could help predict antidepressant efficacy.

Dopamine transporter genotype modulates brain activity during a working memory task in children with ADHD

Dopamine active transporter gene (DAT1) is a candidate gene associated with attention-deficit/hyperactivity disorder (ADHD). The DAT1 variable number tandem repeat (VNTR)-3' polymorphism is functional and 9R carriers have been shown to produce more DAT than 10R homozygotes. We used functional magnetic resonance imaging (fMRI) to investigate the effects of this polymorphism on the neural substrates of working memory (WM) in a small but selected population of children with ADHD, naïve of any psychotropic treatment and without comorbidity. MRI and genotype data were obtained for 36 children (mean age: 10,36 +/- 1,49 years) with combined-type ADHD (9R n = 15) and 25 typically developing children (TDC) (mean age: 9,55 +/- 1,25 years) (9R n = 12). WM performance was similar between conditions. We found a cross-over interaction effect between gene (9R vs. 10R) and diagnosis (TDC vs. ADHD) in the orbito-frontal gyrus, cerebellum and inferior temporal lobe. In these areas, WM-related activity was higher for 9R carriers in ADHD subjects and lower in TDC. In ADHD children only, 10R homozygotes exhibited higher WM-related activity than 9R carriers in a network encompassing the parietal and the temporal lobes, the ventral visual cortex, the orbito-frontal gyrus and the head of the caudate nucleus. There was no significant results in TDC group. Our preliminary findings suggest that DAT1 VNTR polymorphism can modulate WM-related brain activity ADHD children.

Impact of various emulsifiers on ALA bioavailability and chylomicron synthesis through changes in gastrointestinal lipolysis

Formulating healthy food rich in omega 3 fatty acids requires prior knowledge of the parameters influencing their bioavailability and their metabolic fate. In this context, we studied the effects of various emulsifiers widely used in the food industry, on the gastrointestinal lipolysis of flaxseed oil emulsions in an in vitro model and on the intestinal absorption and lymphatic secretion of alpha-linolenic acid (ALA) in rats. In vitro data showed that the emulsification of flaxseed oil with soya lecithin improved the gastric lipolysis of the oil (+30%), while the presence of Tween 80 or of sodium caseinate decreased it (-80% and -40%, respectively). The in vivo data demonstrated that the intestinal absorption and the lymphatic secretion of ALA were improved with soya lecithin (Cmax = 24 mg mL(-1)) and reduced in the presence of sodium caseinate (Cmax = 7 mg mL(-1)) compared to unemulsified flaxseed oil (Cmax = 16 mg mL(-1)); Tween 80 had no effect. In addition, the synthesized chylomicrons were notably larger and more numerous with soya lecithin whereas they were smaller in the presence of sodium caseinate (p < 0.05). This study shows that the intestinal bioavailability of ALA was increased by the emulsification of flaxseed oil with soya lecithin via an improved lipolysis, favouring the intestinal absorption of ALA and the secretion of many large chylomicrons in lymph.

Salivary composition in obese vs normal-weight subjects: towards a role in postprandial lipid metabolism?

In the pathophysiological context of obesity, oral exposure to dietary fat can modulate lipid digestion and absorption, but underlying in-mouth mechanisms have not been clearly identified. Therefore, we tested the hypothesis that salivary components related to dietary fat sensitivity would differ according to body mass index (BMI) and postprandial lipid metabolism in young men. Saliva was collected from nine normal-weight (BMI=22.3±0.5 kg m(-2)) and nine non-morbid obese (BMI=31.7±0.3 kg m(-2)) men before an 8-h postprandial metabolic exploration test involving the consumption of a 40-g fat meal, in which obese subjects revealed a delayed postprandial lipid metabolism. Nine salivary characteristics (flow, protein content, lipolysis, amylase, proteolysis, total antioxidant status, lysozyme, lipocalin 1 and carbonic anhydrase-VI) were investigated. We show that, under fasting conditions, salivary lipolysis was lower in obese vs normal-weight subjects, whereas proteolysis and carbonic anhydrase VI were higher. We reveal through multivariate and Mann-Whitney analysis that differences in fasting salivary lipolysis and proteolysis between both groups are related to differences in postprandial lipid metabolism including exogenous fatty-acid absorption and β-oxidation. These results suggest a potential role of salivary composition on postprandial lipid metabolism and bring novel causal hypotheses on the links between salivary composition, sensitivity to dietary fat oral income and postprandial lipid metabolism according to BMI.

Population kinetics and conditional assessment of the optimal dosage regimen using the P-PHARM software package

The adjustment of individual dosage regimen is an adaptive control process based upon an individual response to a pharmacokinetic model. To attain this objective, it is very helpful to know the characteristics of the population to which the subject belongs, in terms of mean parameters and interindividual variability. Usually the available information consists of incomplete and sparse data. For this reason it is essential to employ a computational methodology based on non-linear mixed-effect procedures in order to obtain a population parameter estimate. A Bayesian methodology can then be applied from the population parameters to the specific data for the individual requiring a dosage adjustment (such data includes drug concentration(s) of the active drug, demographic data, etc). The result of the Bayesian calculation supplies the required individual pharmacokinetic parameters. An optimal dosage regimen can be defined on the basis of therapeutical criteria (concentration ranges) as well as practical constraints such as: the size of available unitary drug dosages, feasible drug intake times, penalties associated with expected concentrations falling outside the therapeutic concentration ranges. In this paper we present the methodology and results obtained using the P-Pharm software tool. P-Pharm implements a non-linear mixed-effect population parameter estimation algorithm based on the EM algorithm. This method allows the inclusion of explicit variables into the calculations, it implements an individual Bayesian parameter estimation procedure and also an algorithm for the conditional assessment of the optimal dosage regimen given a list of practical constraints.