The identification of biomarkers predicting acute and maintenance lithium treatment response in bipolar disorder: A plea for further research attention

Association of BDNF risk variant and dorsolateral cortical thickness with long-term treatment response to valproate in type I bipolar disorder: An exploratory study

Valproate is among the most prescribed drugs for bipolar disorder; however, 87% of patients do not report full long-term treatment response (LTTR) to this medication. One of valproate's suggested mechanisms of action involves the brain-derived neurotrophic factor (BDNF), expressed in the brain areas regulating emotions, such as the prefrontal cortex. Nonetheless, data about the role of BDNF in LTTR and its implications in the structure of the dorsolateral prefrontal cortex (dlPFC) is scarce. We explore the association of BDNF variants and dorsolateral cortical thickness (CT) with LTTR to valproate in bipolar disorder type I (BDI). Twenty-eight BDI patients were genotyped for BDNF polymorphisms rs1519480, rs6265, and rs7124442, and T1-weighted 3D brain scans were acquired. LTTR to valproate was evaluated with Alda's scale. A logistic regression analysis was conducted to evaluate LTTR according to BDNF genotypes and CT. We evaluated CT differences by genotypes with analysis of covariance. LTTR was associated with BDNF rs1519480 and right dlPFC thickness. Insufficient responders with the CC genotype had thicker right dlPFC than TC and TT genotypes. Full responders reported thicker right dlPFC in TC and TT genotypes. In conclusion, different patterns of CT related to BDNF genotypes were identified, suggesting a potential biomarker of LTTR to valproate in our population.

Meta-analysis of soluble tumour necrosis factor receptors in severe mental illnesses

Tumour necrosis factor (TNF), as an innate immune defense molecule, functions through binding to TNF receptor 1 (TNFR1) or TNF receptor 2 (TNFR2). Peripheral levels of soluble TNFR1 (sTNFR1) and soluble TNFR2 (sTNFR2) were widely measured in severe mental illnesses (SMIs) including schizophrenia (SCZ), bipolar disorder (BD) and major depressive disorder (MDD) but inconsistencies existed. Hence, the present meta-analysis was conducted to identify the overall association between plasma/serum sTNFR1 and sTNFR2 levels and SMIs. Published studies were searched using Pubmed and Scopus. Data were analysed using Comprehensive Meta-Analysis version 2. Hedges's g effect sizes and 95% confidence intervals were pooled using fixed-effect or random-effects models. Heterogeneity, publication bias and study quality were assessed. Sensitivity analysis and subgroup analysis were performed. Our findings revealed that sTNFR1 level was significantly higher in SMI, particularly in BD. The sTNFR2 level significantly elevated in SMI but with smaller effect size. These findings further support the association between altered immune system and inflammatory abnormalities in SMI, especially in patients with BD. Subgroup analysis showed that younger age of onset, longer illness duration and psychotropic medication raised both sTNFR levels, especially sTNFR1, as these factors may contribute to the activation of inflammation. Future studies were suggested to identify the causality between TNFR pathway and SCZ, BD and MDD respectively using homogenous group of each SMI, and to determine the longitudinal effect of each psychotropic medication on TNFR pathway.

A Case of Lithium Encephalopathy with Therapeutic Lithium Levels: The Diagnostic Role of EEG

Introduction. Lithium is considered a first-line therapy for both the acute phase and the maintenance of bipolar disorder. Many studies highlighted its neuroprotective and neuroplastic capacity suggesting a potential usefulness in the treatment of neurodegenerative diseases. Despite the undeniable efficacy, lithium clearly presents several adverse effects including neurotoxicity, also known as lithium encephalopathy, regarding both neurological, psychiatric, and cognitive side effects. In this case, adverse reactions are not always related to its serum levels, possibly appearing within the therapeutic range. Case Presentation. We analyzed the case of a bipolar patient who has been uncontinuosly treated with lithium salts since the onset of the psychopathological picture. Over the years, the average values of lithemia always remained around 0.60-0.70 mEq/L, but in 2019, the patient begun to manifest distal tremors and in the mandibular district accompanied, in the following months, by psychomotor slowdown, generalized tremors, reduced alertness, spatiotemporal disorientation, and aphasia. While alterations referable to neurodegenerative diseases were excluded, EEG maintained rhythm alteration 1 year after the probable intoxication. Discussion. This case confirms the central role of EEG for lithium neurotoxicity, while its dosages are in therapeutic range, being plasma levels are not always indicative of liquoral and neuronal lithium's levels. We highlight the importance of an early diagnosis of lithium encephalopathy proposing EEG as an indispensable tool for assessing lithium neurotoxicity both in acute and chronic intoxication.

Prevalence of impaired kidney function in patients with long-term lithium treatment: A systematic review and meta-analysis

OBJECTIVES

Although lithium renal effects have been extensively investigated, prevalence rates of chronic kidney disease (CKD) in lithium-treated patients vary. Our aim was to provide prevalence estimates and related moderators.

METHODS

We performed a systematic review in PubMed/Embase until November 01, 2021, conducting a random effects meta-analysis of studies evaluating CKD prevalence rates in lithium-treated patients calculating overall prevalence ±95% confidence intervals (CIs). Meta-regression analyses included sex, age, body mass index, smoking, hypertension, diabetes, cardiovascular disease, lithium-treatment dose, duration, and blood levels. Subgroup analyses included sample size, diagnoses, and study design. Pooled odds ratios (OR) were estimated for studies including patients receiving nonlithium treatment. Study quality was assessed using the Newcastle-Ottawa scale.

RESULTS

Five, nine, and six trials were rated as high, fair, and low quality, respectively. In 20 studies (n = 25,907 patients), we estimated an overall prevalence of 25.5% (95% CI = 19.8-32.2) of impaired kidney function; despite lack of differences (p = 0.18), prevalence rates were higher in elderly samples than mixed samples of elderly and nonelderly (35.6%, 95% CI = 21.4-52.9, k = 2, n = 3,161 vs. 25.1%, 95% CI = 19.1-31.3, k = 18, n = 22,746). Prevalence rates were associated with longer lithium treatment duration (p = 0.04). Cross-sectional studies provided lower rates than retrospective studies (14.5%, 95% CI = 13.5-15.5, k = 6, n = 4,758 vs. 29.5%, 95% CI = 22.1-38.0, k = 12, n = 17,988, p < 0.001). Compared with 722,529 patients receiving nonlithium treatment, the OR of impaired kidney function in 14,187 lithium-treated patients was 2.09 (95% CI = 1.24-3.51, k = 8, p = 0.005).

CONCLUSIONS

One-fourth of patients receiving long-term lithium may develop impaired kidney function, although research suffers from substantial heterogeneity between studies. This risk may be twofold higher compared with nonlithium treatment and may increase for a longer lithium treatment duration.

Differences in the prophylactic effect of serum lithium levels on depression and mania in bipolar disorder: A dose-response meta-analysis

The optimal serum lithium levels for preventing the recurrence of mood episodes in bipolar disorder are controversial, especially when polarity is considered. The present study aimed to comprehensively examine the dose-response relationship between lithium concentration and risk of recurrence of mood episodes. We conducted a systematic search of major databases before January 2021 (PROSPERO: CRD42021235812). A one-stage, random-effects, restricted cubic splines model was used to estimate the dose-response relationship between lithium concentration and risk of recurrence of any or specific mood episodes (depression or mania). The effect size is shown as odds ratio (OR). Our meta-analysis included six randomised controlled trials with a total of 975 participants. The dose-response curve showed that increased serum concentrations were associated with a gradual decrease in the risk of any mood episodes (OR 0.50 at 0.60 mmol/l, OR 0.15 at 1.20 mmol/l). The risk of depression decreased slightly with a concentration of 0.60 mmol/l (OR 0.83) but dropped rapidly as the concentration increased to 1.20 mmol/l (OR 0.39). By contrast, the risk for mania initially decreased steadily (OR 0.44), but decreased only marginally (OR 0.30) as the concentration increased. To reduce the recurrence risk to 56%, prevention of depression required a higher concentration than that required for mania (1.13 mmol/l vs. 0.60 mmol/l). Our results suggest a negative dose-response relationship between serum lithium levels and risk of recurrence. In particular, the different preventive effects of serum concentration on depression and mania will be an important clinical reference.

Circular RNA circCCNT2 is upregulated in the anterior cingulate cortex of individuals with bipolar disorder

Gene expression dysregulation in the brain has been associated with bipolar disorder, but little is known about the role of non-coding RNAs. Circular RNAs are a novel class of long noncoding RNAs that have recently been shown to be important in brain development and function. However, their potential role in psychiatric disorders, including bipolar disorder, has not been well investigated. In this study, we profiled circular RNAs in the brain tissue of individuals with bipolar disorder. Total RNA sequencing was initially performed in samples from the anterior cingulate cortex of a cohort comprised of individuals with bipolar disorder (N = 13) and neurotypical controls (N = 13) and circular RNAs were identified and analyzed using "circtools". Significant circular RNAs were validated by RT-qPCR and replicated in the anterior cingulate cortex in an independent cohort (24 bipolar disorder cases and 27 controls). In addition, we conducted in vitro studies using B-lymphoblastoid cells collected from bipolar cases (N = 19) and healthy controls (N = 12) to investigate how circular RNAs respond following lithium treatment. In the discovery RNA sequencing analysis, 26 circular RNAs were significantly differentially expressed between bipolar disorder cases and controls (FDR < 0.1). Of these, circCCNT2 was RT-qPCR validated showing significant upregulation in bipolar disorder (p = 0.03). This upregulation in bipolar disorder was replicated in an independent post-mortem human anterior cingulate cortex cohort and in B-lymphoblastoid cell culture. Furthermore, circCCNT2 expression was reduced in response to lithium treatment in vitro. Together, our study is the first to associate circCCNT2 to bipolar disorder and lithium treatment.

Novel experimental and early investigational drugs for the treatment of bipolar disorder

INTRODUCTION

The quest toward more effective treatments for bipolar disorder (BD) solicits novel drugs and further research on the underpinning neurobiology. The present review aims to critically appraise the existing evidence about the pharmacological treatment of BD toward the development of novel treatment avenues.

AREAS COVERED

The present review appraises animal and human studies concerning both the currently available psychotropic drugs, and the general medicine drugs which may represent a path toward the development of novel drugs for BD. PubMed and Scopus were last accessed on February 20^th, 2021 for records indexed upon inception relevant to the pharmacological treatment of BD. Immune-modulating agents, anti-inflammatory agents, and glutamate antagonists represent the most intriguing potential targets for the development of new drugs for BD, thus receiving critical appraisal in the present text.

EXPERT OPINION

Regardless of the neurobiological pathways worthy of investigation toward the development of experimental drugs for BD, several unmet needs need to be addressed first. In particular, several biomarkers are altered in BD. However, it is the opinion herein expressed by the authors that it remains uncertain what comes first, that is peripheral changes or the disease.

Prefrontal cortical thickness and clinical characteristics of long-term treatment response to valproate in bipolar disorder

Valproate compositions are frequently used to treat bipolar disorder (BD); however, 87% of patients do not report full response in the long-term. There is scarce information about the clinical features and brain structural characteristics of long-term treatment response (LTTR) to this medication. In this study, we aim to evaluate the clinical characteristics and prefrontal cortical thickness (CT) of LTTR to valproate in BD. We evaluated 30 BD outpatients on valproate treatment, and 20 controls with a 3T T1-weighted 3D brain scan and Alda's scale for LTTR. An analysis of covariance was used to evaluate CT measures and a logistic regression was conducted to predict the full response (FR) using clinical features and CT measures. Patients with an insufficient response (IR) reported thinner right frontal eye fields, anterior and dorsolateral prefrontal cortexes compared with controls. FR patients presented thicker right dorsolateral prefrontal cortex than IR and no differences with controls. Patients with mixed features presented increased odds of achieving FR, while CT measures reported non-significant results. This is the first study to report mixed features as a clinical predictor of valproate LTTR. Our findings also suggest better preservation of the right prefrontal cortex of subjects with FR to valproate.

Pharmacogenomics: A road ahead for precision medicine in psychiatry

Psychiatric genomics is providing insights into the nature of psychiatric conditions that in time should identify new drug targets and improve patient care. Less attention has been paid to psychiatric pharmacogenomics research, despite its potential to deliver more rapid change in clinical practice and patient outcomes. The pharmacogenomics of treatment response encapsulates both pharmacokinetic ("what the body does to a drug") and pharmacodynamic ("what the drug does to the body") effects. Despite early optimism and substantial research in both these areas, they have to date made little impact on clinical management in psychiatry. A number of bottlenecks have hampered progress, including a lack of large-scale replication studies, inconsistencies in defining valid treatment outcomes across experiments, a failure to routinely incorporate adverse drug reactions and serum metabolite monitoring in study designs, and inadequate investment in the longitudinal data collections required to demonstrate clinical utility. Nonetheless, advances in genomics and health informatics present distinct opportunities for psychiatric pharmacogenomics to enter a new and productive phase of research discovery and translation.

Recurrence of Mania or Depression Among Adult Bipolar Patients Who Continued Using Lithium: A Single-group Summary Meta-analysis of Randomized Trials

BACKGROUND

The exact recurrence rate of bipolar disorder in patients receiving lithium maintenance phase treatment and the modifiers associated with recurrence are still unknown.

METHODS

We searched Embase, PubMed, and CENTRAL from inception until April 28, 2020. Outcomes included recurrence rate of any mood episode, depressive episodes, and manic/hypomanic/mixed episodes; all-cause discontinuation rate; and discontinuation rate due to adverse events. A random-effects model, single-group summary meta-analysis was conducted. A meta-regression analysis to examine whether the modifiers (total number of patients, %female, mean age, duration of study, duration of preliminary phase, publication year, bipolar disorder type, mood status at recruitment, presence of a placebo arm, sponsorship, enrichment design, number of treatment arms, and risk of bias for blinding or randomization) were associated with the event rate of the outcomes was also performed.

RESULTS

We identified 21 randomized trials (n = 1,415; mean study duration, 78.40 ± 32.10 weeks; %female, 54.85%; mean age, 43.47 ± 4.88 years). The event rates (95% confidence interval [CI]) were as follows: recurrence of any mood episode, 39.8% (32.8%, 47.1%); depressive episodes, 25.6% (18.8%, 34.0%); manic/hypomanic/mixed episodes, 18.5% (13.7%, 24.7%); all-cause discontinuation rate, 67.0% (57.2%, 75.5%); and discontinuation rate due to adverse events, 8.7% (5.1%, 14.7%). After adjusting for multiple testing, our meta-regression analysis showed association only between the all-cause discontinuation rate and presence of a placebo arm.

CONCLUSIONS

The recurrence rate of depressive episodes seemed to be higher than the recurrence rate of manic/hypomanic/mixed episodes. The all-cause discontinuation rate was high. However, the studies included in our meta-analysis were of short duration.

Epigenetics in bipolar disorder: a critical review of the literature

INTRODUCTION

Bipolar disorder (BD) is a chronic, disabling disease characterised by alternate mood episodes, switching through depressive and manic/hypomanic phases. Mood stabilizers, in particular lithium salts, constitute the cornerstone of the treatment in the acute phase as well as for the prevention of recurrences. The pathophysiology of BD and the mechanisms of action of mood stabilizers remain largely unknown but several pieces of evidence point to gene x environment interactions. Epigenetics, defined as the regulation of gene expression without genetic changes, could be the molecular substrate of these interactions. In this literature review, we summarize the main epigenetic findings associated with BD and response to mood stabilizers.

METHODS

We searched PubMed, and Embase databases and classified the articles depending on the epigenetic mechanisms (DNA methylation, histone modifications and non-coding RNAs).

RESULTS

We present the different epigenetic modifications associated with BD or with mood-stabilizers. The major reported mechanisms were DNA methylation, histone methylation and acetylation, and non-coding RNAs. Overall, the assessments are poorly harmonized and the results are more limited than in other psychiatric disorders (e.g. schizophrenia). However, the nature of BD and its treatment offer excellent opportunities for epigenetic research: clear impact of environmental factors, clinical variation between manic or depressive episodes resulting in possible identification of state and traits biomarkers, documented impact of mood-stabilizers on the epigenome.

CONCLUSION

Epigenetic is a growing and promising field in BD that may shed light on its pathophysiology or be useful as biomarkers of response to mood-stabilizer.

Sensitivity of yeast to lithium chloride connects the activity of YTA6 and YPR096C to translation of structured mRNAs

Lithium Chloride (LiCl) toxicity, mode of action and cellular responses have been the subject of active investigations over the past decades. In yeast, LiCl treatment is reported to reduce the activity and alters the expression of PGM2, a gene that encodes a phosphoglucomutase involved in sugar metabolism. Reduced activity of phosphoglucomutase in the presence of galactose causes an accumulation of intermediate metabolites of galactose metabolism leading to a number of phenotypes including growth defect. In the current study, we identify two understudied yeast genes, YTA6 and YPR096C that when deleted, cell sensitivity to LiCl is increased when galactose is used as a carbon source. The 5’-UTR of PGM2 mRNA is structured. Using this region, we show that YTA6 and YPR096C influence the translation of PGM2 mRNA.

Lithium treatment in the era of personalized medicine

In 1949, an Australian psychiatrist, John Cade, reported on the antimanic efficacy of lithium carbonate, which is regarded as an introduction of lithium into contemporary psychiatry. Since the 1960s, lithium has been a precursor of mood stabilizers and has become first-choice drug for the prevention of affective episodes in mood disorders. For nearly four decades, lithium has also been used for the augmentation of antidepressant drugs in treatment-resistant depression. The knowledge of clinical and biological factors connected with the capability of long-term lithium treatment to prevent manic and depressive recurrences makes an important element of the personalized medicine of mood disorders. Excellent prophylactic lithium responders can be characterized by distinct mood episodes, with full remissions between them, the absence of other psychiatric morbidity, and the family history of bipolar illness. In recent years, many other clinical and biological factors connected with such a response have been identified, helping to select the best candidates for lithium prophylaxis. The antisuicidal effect of lithium during its long-term administration has been demonstrated and should also be taken into account as the element of personalized medicine for the pharmacological prophylaxis of patients with mood disorders. Several studies pertaining to personalized medicine were also dedicated to lithium treatment of acute mood episodes. Lithium still has a value in the treatment of mania and bipolar depression. However, it seems that the more important indication would be the augmentation of antidepressant drugs in treatment-resistant depression. The factors connected with the efficacy of lithium in these conditions are reviewed.

Clinical correlates associated with the long-term response of bipolar disorder patients to lithium, valproate or lamotrigine: A retrospective study

Background

Although mood stabilizers such as lithium (LIT), valproate (VAL), and lamotrigine (LMT) appear to be efficacious treatments for bipolar disorder (BD) in research settings, the long-term response to these mood stabilizers in clinical practice is highly variable among individuals. Thus, the present study examined the characteristics associated with good or insufficient responses to long-term treatment with LIT, VAL, or LMT for BD.

Methods

This study retrospectively analyzed the medical records of patients who visited an outpatient clinic with a diagnosis of BD I or II. Data from patients who were treated with one of three mood stabilizing medications (LIT, VAL, or LMT) for more than 6 months were selected, and the long-term treatment responses were evaluated using the Alda scale. For the purposes of this study, two response categories were formed: insufficient response (ISR), including non-response or poor response (Alda total score ≤ 6), and good response (GR; Alda total score ≥ 7).

Results

Of the 645 patients included in the present study, 172 were prescribed LIT, 320 were prescribed VAL, and 153 were prescribed LMT for at least 6 months. A binary logistic regression analysis revealed that a diagnosis of BD II (odds ratio [OR], 8.868; 95% confidence interval [CI], 1.123–70.046; p = 0.038), comorbid alcohol/substance use disorder (OR, 4.238; 95% CI, 1.154–15.566; p = 0.030), and a history of mixed episodes (OR, 4.363; 95% CI, 1.191–15.985; p = 0.026) were significant predictors of LIT-ISR. Additionally, a depressive-predominant polarity significantly predicted LMT-GR (OR, 8.586; 95% CI, 2.767–26.644; p < 0.001).

Conclusion

The present findings demonstrated that patients with a diagnosis of BD II, a comorbid alcohol/substance problem, or a history of mixed episodes were not likely to respond to LIT treatment. Additionally, LMT might be a better treatment choice for patients with a depressive-predominant polarity.

Whole Genome Expression Analyses of miRNAs and mRNAs Suggest the Involvement of miR-320a and miR-155-3p and their Targeted Genes in Lithium Response in Bipolar Disorder

Lithium is the mainstay in the maintenance of bipolar disorder (BD) and the most efficacious pharmacological treatment in suicide prevention. Nevertheless, its use is hampered by a high interindividual variability and important side effects. Genetic and epigenetic factors have been suggested to modulate lithium response, but findings so far have not allowed identifying molecular targets with predictive value. In this study we used next generation sequencing to measure genome-wide miRNA expression in lymphoblastoid cell lines from BD patients excellent responders (ER, n = 12) and non-responders (NR, n = 12) to lithium. These data were integrated with microarray genome-wide expression data to identify pairs of miRNA/mRNA inversely and significantly correlated. Significant pairs were prioritized based on strength of association and in-silico miRNA target prediction analyses to select candidates for validation with qRT-PCR. Thirty-one miRNAs were differentially expressed in ER vs. NR and inversely correlated with 418 genes differentially expressed between the two groups. A total of 331 of these correlations were also predicted by in-silico algorithms. miR-320a and miR-155-3p, as well as three of their targeted genes (CAPNS1 (Calpain Small Subunit 1) and RGS16 (Regulator of G Protein Signaling 16) for miR-320, SP4 (Sp4 Transcription Factor) for miR-155-3p) were validated. These miRNAs and mRNAs were previously implicated in psychiatric disorders (miR-320a and SP4), key processes of the central nervous system (CAPNS1, RGS16, SP4) or pathways involved in mental illnesses (miR-155-3p). Using an integrated approach, we identified miRNAs and their targeted genes potentially involved in lithium response in BD.

A systematic review and meta-analysis of clinical predictors of lithium response in bipolar disorder

OBJECTIVE

To determine clinical predictors of lithium response in bipolar disorder.

METHODS

Systematic review of studies examining clinical predictors of lithium response was conducted. Meta-analyses were performed when ≥2 studies examined the same potential predictor.

RESULTS

A total of 71 studies, including over 12 000 patients, identified six predictors of good response: mania-depression-interval sequence [odds ratio (OR): 4.27; 95% CI: 2.61, 6.97; P < 0.001], absence of rapid cycling (OR for rapid cycling: 0.30; 95% CI: 0.17, 0.53; P < 0.001), absence of psychotic symptoms (OR for psychotic symptoms: 0.52; 95% CI: 0.34, 0.79; P = 0.002), family history of bipolar disorder (OR: 1.61; 95% CI: 1.03, 2.52; P = 0.036), shorter prelithium illness duration [standardised mean difference (SMD): -0.26; 95% CI: -0.41, -0.12; P < 0.001] and later age of onset (SMD: 0.17; 95% CI: 0.02, 0.36; P = 0.029). Additionally, higher body mass index was associated with poor response in two studies (SMD: -0.61; 95% CI: -0.90, -0.32; P < 0.001). There was weak evidence for number of episodes prior to lithium treatment (SMD: -0.42; 95% CI: -0.84, -0.01; P = 0.046), number of hospitalisations before lithium (SMD: -0.40; 95% CI: -0.81, 0.01; P = 0.055) and family history of lithium response (OR: 10.28; 95% CI: 0.66, 161.26; P = 0.097).

CONCLUSIONS

The relative importance of these clinical characteristics should be interpreted with caution because of potential biases and confounding.

A randomised controlled trial of a mitochondrial therapeutic target for bipolar depression: mitochondrial agents, N-acetylcysteine, and placebo

BACKGROUND

A phasic dysregulation of mitochondrial bioenergetics may operate in bipolar disorder, increased in mania and decreased in depression. We aimed to examine efficacy of two add-on treatments in bipolar depression: N-acetylcysteine (NAC) and NAC with a combination of nutraceutical agents that may increase mitochondrial biogenesis.

METHODS

A three-arm 16-week, double-blind, randomised, placebo-controlled trial, adjunctive to usual treatment, was conducted. Participants (n = 181) with bipolar disorder and current depressive symptoms were randomised to 2000 mg/day NAC (n = 59), 2000 mg/day NAC with the combination nutraceutical treatment (CT, n = 61), or placebo (n = 61). The primary outcome was change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline to week 16. Young Mania Rating Scale, Clinical Global Impression (CGI)-Improvement and CGI-Severity scales, Patient Global Impression scale, Social and Occupational Functioning Assessment Scale (SOFAS), Longitudinal Interval Follow-Up Evaluation - Range of Impaired Functioning Tool (LIFE-RIFT), and Quality of Life Enjoyment, and Satisfaction Questionnaire Short Form (Q-LES-Q-SF) were secondary outcomes.

RESULTS

One hundred forty-eight participants had post-randomisation data and were analysed (NAC = 52, CT = 47, Placebo = 49). No between-group differences were found for the rate of change between baseline and 16 weeks on any of the clinical and functioning variables. Improvements in MADRS, BDRS, SOFAS, and LIFE-RIFT scores from baseline to the week 20 post-discontinuation visit were significantly greater in the CT group compared to those in the placebo. At week 20, the CGI-I was significantly lower in the CT group versus placebo. Gastrointestinal symptoms were significantly greater in the NAC than in the placebo group.

CONCLUSIONS

These overall negative results, with no significant differences between groups detected at the primary outcome but some positive secondary signals, suggest either delayed benefit of the combination or an improvement of symptoms on withdrawal which warrants further exploration regarding the composition, mechanisms, and application of mitochondrial agents in illnesses characterised by mitochondrial dysfunction.

TRIAL REGISTRATION

ANZCTR ( ACTRN12612000830897 ).