Folate concentration in Chinese psychiatric outpatients on long-term lithium treatment

Folate and Its Significance in Depressive Disorders and Suicidality: A Comprehensive Narrative Review

Depressive disorders pose significant challenges to global public health, necessitating effective prevention and management strategies. Notably, the occurrence of suicide frequently coincides with depressive episodes. Suicide is as a paramount global health concern that demands efficacious preventive strategies. Current psychiatric approaches heavily rely on pharmacological interventions but have had limited success in addressing the global burden of mental health issues. Suboptimal nutrition, with its impact on the neuroendocrine system, has been implicated in the underlying pathology of depressive disorders. Folate, a group of water-soluble compounds, plays a crucial role in various central nervous system functions. Depressed individuals often exhibit low levels of serum and red blood cell folate. Multiple studies and systematic reviews have investigated the efficacy of folic acid and its derivative, L-methylfolate, which can cross the blood-brain barrier, as stand-alone or adjunct therapies for depression. Although findings have been mixed, the available evidence generally supports the use of these compounds in depressed individuals. Recent studies have established links between the one-carbon cycle, folate-homocysteine balance, immune system function, glutamate excitation via NMDA (N-methyl-D-aspartate) receptors, and gut microbiome eubiosis in mood regulation. These findings provide insights into the complex neurobiological mechanisms underlying the effects of folate and related compounds in depression. Through a comprehensive review of the existing literature, this study aims to advance our understanding of the therapeutic potential of folic acid and related compounds in depression treatment. It also seeks to explore their role in addressing suicidal tendencies and shed light on the neurobiological mechanisms involved, leveraging the latest discoveries in depression research.

Homocysteine as a peripheral biomarker in bipolar disorder: A meta-analysis

Background:

Bipolar disorder (BD) is a psychiatric disorder with an uncertain aetiology. Recently, special attention has been given to homocysteine (Hcy), as it has been suggested that alterations in 1-carbon metabolism might be implicated in diverse psychiatric disorders. However, there is uncertainty regarding possible alterations in peripheral Hcy levels in BD.

Methods:

This study comprises a meta-analysis comparing serum and plasma Hcy levels in persons with BD and healthy controls. We conducted a systematic search for all eligible English and non-English peer-reviewed articles.

Results:

Nine cross-sectional studies were included in the meta-analyses, providing data on 1547 participants. Random-effects meta-analysis showed that serum and plasma levels of Hcy were increased in subjects with BD in either mania or euthymia when compared to healthy controls, with a large effect size in the mania group (g= 0.98, 95% CI: 0.8–1.17,P< 0.001,n= 495) and a small effect in the euthymia group (g= 0.3, 95% CI: 0.11–0.48,P= 0.002,n= 1052).

Conclusions:

Our meta-analysis provides evidence that Hcy levels are elevated in persons with BD during mania and euthymia. Peripheral Hcy could be considered as a potential biomarker in BD, both of trait (since it is increased in euthymia), and also of state (since its increase is more accentuated in mania). Longitudinal studies are needed to clarify the relationship between bipolar disorder and Hcy, as well as the usefulness of peripheral Hcy as both a trait and state biomarker in BD.

Contribution of methotrexate in precipitation of manic episode in bipolar affective disorder explored: a case report

Bipolar affective disorder is characterized by recurring episodes of mania with or without, but commonly with, episodes of depression. It usually begins in adolescence and can cause enduring and substantial impairment if left untreated. It needs a long-term treatment with mood stabilizers to prevent relapses. Elevated or depressed mood relapses can be either primary or secondary. However, primary mood relapses can occur without a significant precipitating factor, more often tending to occur following stressful life events or discontinuation of mood stabilizer medications. Secondary mood relapses can be caused by many conditions, such as physical illnesses, substance misuse and medications. When a mental illness coexists with another physical illness and the treatment of one complicates the other, it adds complexity to the selection of appropriate pharmacological regime for either condition. In this paper, the authors present a case of bipolar affective disorder who had two episodes of mania likely precipitated by methotrexate, which were reversed by the withdrawal of the offending drug (methotrexate). To the best of the authors' knowledge, to date there have been no published reports in the literature in which methotrexate, an immunosuppressive and a cytotoxic drug, precipitated a manic episode in a patient with bipolar affective disorder.

Low red cell folate levels are associated with poor response to nortriptyline in major depression

BACKGROUND

There has been a long interest in the relationship between folate and depression.

METHODS

In this paper, we report baseline measures of red cell folate that were collected during a randomized trial of 107 patients with major depression. Red cell folate levels were examined for association with percentage improvement in depressive symptoms during treatment with fluoxetine or nortriptyline. The influences of possible confounding factors were assessed.

RESULTS

The low red cell folate group (defined in relation to the median) had a significantly poorer response to nortriptyline. This effect of red cell folate levels was not present in those treated with fluoxetine. No relationships were found between red cell folate levels and possible confounding factors of age, nutritional status, alcohol history, depression subtype, depression severity and chronicity of depression.

CONCLUSION

Response to nortriptyline was affected by red cell folate status. It may, therefore, be beneficial to consider folate augmentation in patients with major depression, particularly if treated with nortriptyline.

Treatment of depression: time to consider folic acid and vitamin B12

We review the findings in major depression of a low plasma and particularly red cell folate, but also of low vitamin B12 status. Both low folate and low vitamin B12 status have been found in studies of depressive patients, and an association between depression and low levels of the two vitamins is found in studies of the general population. Low plasma or serum folate has also been found in patients with recurrent mood disorders treated by lithium. A link between depression and low folate has similarly been found in patients with alcoholism. It is interesting to note that Hong Kong and Taiwan populations with traditional Chinese diets (rich in folate), including patients with major depression, have high serum folate concentrations. However, these countries have very low life time rates of major depression. Low folate levels are furthermore linked to a poor response to antidepressants, and treatment with folic acid is shown to improve response to antidepressants. A recent study also suggests that high vitamin B12 status may be associated with better treatment outcome. Folate and vitamin B12 are major determinants of one-carbon metabolism, in which S-adenosylmethionine (SAM) is formed. SAM donates methyl groups that are crucial for neurological function. Increased plasma homocysteine is a functional marker of both folate and vitamin B12 deficiency. Increased homocysteine levels are found in depressive patients. In a large population study from Norway increased plasma homocysteine was associated with increased risk of depression but not anxiety. There is now substantial evidence of a common decrease in serum/red blood cell folate, serum vitamin B12 and an increase in plasma homocysteine in depression. Furthermore, the MTHFR C677T polymorphism that impairs the homocysteine metabolism is shown to be overrepresented among depressive patients, which strengthens the association. On the basis of current data, we suggest that oral doses of both folic acid (800 microg daily) and vitamin B12 (1 mg daily) should be tried to improve treatment outcome in depression.

Folate for depressive disorders: systematic review and meta-analysis of randomized controlled trials

The objective of this review was to determine the effectiveness, adverse effects and acceptability of folate in the treatment of depression. Electronic databases (Cochrane Controlled Trials Register and the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register) and reference lists were searched, and authors, experts and pharmaceutical companies contacted to identify randomized controlled trials that compared treatment with folic acid or 5'-methyltetrahydrofolic acid to an alternative treatment, for patients with a diagnosis of depressive disorder. Three randomized trials (247 participants) were included. Two studies assessed the use of folate in addition to other treatment, and found that adding folate reduced Hamilton Depression Rating Scale (HDRS) scores on average by a further 2.65 points [95% confidence interval (CI) 0.38-4.93]. Fewer patients treated with folate experienced a reduction in their HDRS score of less than 50% at 10 weeks (relative risk 0.47, 95% CI 0.24-0.92). The remaining study found no statistically significant difference when folate alone was compared with trazodone. The identified trials did not find evidence of any problems with the acceptability or safety of folate. The limited available evidence suggests folate may have a potential role as a supplement to other treatment for depression. It is currently unclear if this is the case both for people with normal folate levels, and for those with folate deficiency.

The influence of folate serum levels on depressive mood and mental processing in patients with epilepsy treated with enzyme-inducing anti-epileptic drugs

BACKGROUND

Folate deficiency is common in patients with epilepsy and also occurs in patients with depression or cognitive deficits.

OBJECTIVE

This study investigates whether low serum folate levels may contribute to depressive mood and difficulties in mental processing in patients with epilepsy treated with anti-epileptic drugs inducing the cytochrome P450.

METHODS

We analysed the serum folate levels, the score in the Self Rating Depression Scale (SDS) and the results of a bedside test in mental processing in 54 patients with epilepsy.

RESULTS

There was a significant negative correlation between the serum folate levels and the score in SDS and significant positive correlations between the score in SDS and the time needed to process an interference task or a letter-reading task.

CONCLUSIONS

Low serum folate levels may contribute to depressive mood and therefore to difficulties in mental processing. Further studies utilizing total plasma homocysteine as a sensitive measure of functional folate deficiency and more elaborate tests of mental processing are required to elucidate the impact of folate metabolism on depressive mood and cognitive function in patients with epilepsy.

Folate for depressive disorders

BACKGROUND

There are a number of effective interventions for the treatment of depression. It is possible that the efficacy of these treatments will be improved further by the use of adjunctive therapies such as folate.

OBJECTIVES

1. To determine the effectiveness of folate in the treatment of depression 2. To determine the adverse effects and acceptability of treatment with folate.

SEARCH STRATEGY

The Cochrane Controlled Trials Register (CCTR), and the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR) incorporating results of group searches of EMBASE, MEDLINE, LILACS, CINAHL, PSYNDEX and PsycLIT were searched. Reference lists of relevant papers and major textbooks of affective disorder were checked. Experts in the field and pharmaceutical companies were contacted regarding unpublished material.

SELECTION CRITERIA

All randomised controlled trials that compared treatment with folic acid or 5'-methyltetrahydrofolic acid to an alternative treatment, whether another antidepressant medication or placebo, for patients with a diagnosis of depressive disorder (diagnosed according to explicit criteria).

DATA COLLECTION AND ANALYSIS

Data were independently extracted from the original reports by two reviewers. Statistical analysis was conducted using Review Manager version 4.1.

MAIN RESULTS

Three trials involving 247 people were included. Two studies involving 151 people assessed the use of folate in addition to other treatment, and found that adding folate reduced Hamilton Depression Rating Scale scores on average by a further 2.65 points (95% confidence interval 0.38 to 4.93). Fewer patients treated with folate experienced a reduction in their HDRS score of less than 50% at ten weeks (relative risk (RR) 0.47, 95% CI 0.24 to 0.92) The number needed to treat with folate for one additional person to experience a 50% reduction on this scale was 5 (95% confidence interval 4 to 33). One study involving 96 people assessed the use of folate instead of the antidepressant trazodone and did not find a significant benefit from the use of folate. The trials identified did not find evidence of any problems with the acceptability or safety of folate.

REVIEWER'S CONCLUSIONS

The limited available evidence suggests folate may have a potential role as a supplement to other treatment for depression. It is currently unclear if this is the case both for people with normal folate levels, and for those with folate deficiency.

A controlled study of folate levels in Chinese inpatients with major depression in Hong Kong

BACKGROUND

Although Western and, in particular, British studies have revealed a substantial rate of hypofolatemia in patients with depression, few such studies have been conducted in Asian populations.

METHODS

A group of 117 newly admitted inpatients with DSM-III-R major depression and 72 healthy controls underwent blood investigations and psychometric assessments.

RESULTS

Patients had a significantly lower mean serum folate level (24.6+/-10.2 vs. 30.3+/-11.4 nmol/l, P < 0.001) but a higher mean erythrocyte folate level (801.8+/-284.6 nmol/l vs. 699.5+/-248.7 nmol/l, P < 0.01) than control subjects. No patient or control subjects had low folate, while only four patients (3.4%) and six control subjects (8.3%) had low erythrocyte folate. Folate levels were not related to patients' age, duration of illness, Hamilton Depression Rating Scale, Beck Depression Inventory and Global Assessment Scale scores, and prior psychotropic drug usage. Both patients and control subjects revealed a high intake of green vegetables.

CONCLUSION

Patients' lower serum folate level was likely to be secondary to their depression but, being well in the normal range, should not have aggravated their depressive symptoms. Culturally patterned health beliefs and dietary practices can influence the connection between folate status and depression in different societies.

LIMITATIONS

Patients were not drug-free, while the lack of detailed dietary analysis and longitudinal data on folate level and psychiatric outcome tempered the above conclusion.

CLINICAL RELEVANCE

Since normofolatemia is normative in Hong Kong, the routine screening of folate levels in Chinese depressive patients is not indicated. However, a double-blind, placebo-controlled trial may be useful for finding out whether Chinese patients will still benefit from folate pharmacotherapy.

A prevalence study of folate deficiency in a psychiatric in-patient population

Controlled clinical trials in the UK have shown folate deficiency in psychiatric patients, and it has been suggested that such deficiency is most likely to occur among patients with affective disorders. Studies have led to the use of folate as an adjunct to therapy in such patients. The present paper describes a preliminary investigation into the red cell folate status of psychiatric patients in a general hospital unit compared with age- and sex-matched healthy controls, using up-to-date assays and strict entry criteria and overall improved methods on previous studies. The study showed that, although there is a trend for psychiatric patients to have lower serum folate levels than controls, there is no statistically significant difference in folate levels as measured by red cell folate, a more reliable measure of folate status, between healthy controls and psychiatric patients, and all but one of the patients had normal haematological indices.