Association of metformin and depression in patients with type 2 diabetes

Insulin Resistance: The Role in Comorbid Type 2 Diabetes Mellitus and Depression

Insulin resistance (IR) plays a significant role in the pathophysiology of comorbid type 2 diabetes mellitus (T2DM) and depression (CDD) through multifaceted mechanisms, including dysregulation of insulin signaling (both central and peripheral), neuroendocrine disturbances (e.g., hypothalamic-pituitary-adrenal axis dysfunction and impairment of monoaminergic neurotransmission), chronic inflammation, oxidative stress, disruption of the microbiota-gut-brain axis, reduced brain-derived neurotrophic factor levels, and altered synaptic plasticity. These IR-associated pathways may predispose individuals to depressive symptoms or exacerbate existing mood disorders. A comprehensive understanding of these mechanisms is critical for developing integrated therapeutic strategies that concurrently target metabolic and psychiatric dysfunction. Antidepressant medications exhibit divergent effects on glucose metabolism. Tricyclic antidepressants, particularly amitriptyline and nortriptyline, worsen metabolic profiles by exacerbating IR, promoting weight gain, and inducing hyperglycemia, thereby increasing diabetes risk with prolonged use. Consequently, tricyclic antidepressants should be avoided in metabolically vulnerable populations unless alternatives are unavailable. Mirtazapine presents a paradoxical profile-while its appetite-stimulating effects often lead to weight gain (a known IR risk factor for IR), some evidence suggests potential β-cell function preservation, necessitating cautious use of mirtazapine in individuals with metabolic syndrome. Among selective serotonin reuptake inhibitors, fluoxetine and escitalopram demonstrate favorable metabolic effects, including improved insulin sensitivity and glycemic control, though hypoglycemia risk (particularly with concomitant sulfonylureas) warrants monitoring. Bupropion, a norepinephrine-dopamine reuptake inhibitor, uniquely promotes weight loss and enhances glycemic control, making it a first-line option for depression comorbid with obesity or T2DM. Agomelatine, with its neutral metabolic profile and circadian rhythm-modulating properties, represents a safer alternative for patients with metabolic concerns. Concurrently, certain antidiabetic agents show promise in managing depression. Metformin and sodium-glucose cotransporter-2 inhibitors may be prioritized for diabetic patients at risk for depression, while glucagon-like peptide-1 receptor agonists appear particularly beneficial for obesity-related mood disturbances. Thiazolidinediones offer value in treatment-resistant cases, whereas insulin secretagogues should be used cautiously in psychiatrically vulnerable individuals. Future research should prioritize three key directions: (1) Mechanistic investigations using advanced neuroimaging, such as intranasal insulin, to elucidate the contribution of IR to depressive phenotypes and evaluate novel interventions, such as intranasal insulin; (2) Precision medicine approaches incorporating biomarkers, including genetic polymorphisms, inflammatory markers, and gut microbiome signatures, to optimize antidepressant selection and develop personalized treatment algorithms; and (3) Therapeutic innovation, including dual GLP-1/GIP agonists and anti-inflammatory-antidepressant combinations, alongside digital health technologies (e.g., continuous glucose monitoring coupled with mood tracking), will enable real-time, data-driven management. These advances will be instrumental in establishing integrated care paradigms for this comorbidity, which intertwines metabolic and psychiatric conditions.

Metformin as a potential antidepressant: Mechanisms and therapeutic insights in depression

Depression is one of the most disabling psychiatric disorders, whose pathophysiology has not been fully understood. Increasing numbers of preclinical studies have highlighted that metformin, as the first-line hypoglycaemic agent, has a potential pleiotropic effect on depression. Moreover, there is emerging evidence that metformin shows antidepressant activity and improves depressive symptoms in rodent models of depression. However, the exact role and underlying mechanism of metformin in depression remain unclear and still need to be investigated. Recent studies suggest that metformin not only improves neuronal damage and structural plasticity in the hippocampus but also enhances the antidepressant effect of antidepressants. Therefore, in this review, we summarize the existing evidence for the use of metformin as a psychopharmaceutical and elaborate on the underlying mechanisms of metformin in mitigating the onset and progression of depression, as well as the associated biochemical signaling pathways and targets involved in the pathogenesis of depression. After reviewing several studies, we conclude that metformin helps reduce depressive symptoms by targeting multiple pathways, including the regulation of neurotransmitters, enhanced neurogenesis, anti-inflammatory effects, and changes in gut microbiota. We aim to gain a deeper understanding of the mechanism of action of metformin and provide new insights into its clinical value in the prevention and therapy of depression.

Mitochondria and the Repurposing of Diabetes Drugs for Off-Label Health Benefits

This review describes our current understanding of the role of the mitochondria in the repurposing of the anti-diabetes drugs metformin, gliclazide, GLP-1 receptor agonists, and SGLT2 inhibitors for additional clinical benefits regarding unhealthy aging, long COVID, mental neurogenerative disorders, and obesity. Metformin, the most prominent of these diabetes drugs, has been called the "Drug of Miracles and Wonders," as clinical trials have found it to be beneficial for human patients suffering from these maladies. To promote viral replication in all infected human cells, SARS-CoV-2 stimulates the infected liver cells to produce glucose and to export it into the blood stream, which can cause diabetes in long COVID patients, and metformin, which reduces the levels of glucose in the blood, was shown to cut the incidence rate of long COVID in half for all patients recovering from SARS-CoV-2. Metformin leads to the phosphorylation of the AMP-activated protein kinase AMPK, which accelerates the import of glucose into cells via the glucose transporter GLUT4 and switches the cells to the starvation mode, counteracting the virus. Diabetes drugs also stimulate the unfolded protein response and thus mitophagy, which is beneficial for healthy aging and mental health. Diabetes drugs were also found to mimic exercise and help to reduce body weight.

Metformin treatment improves depressive symptoms associated with type 2 diabetes: A 24-week longitudinal study

OBJECTIVE

Metformin is a medication that is widely used for lowering blood sugar in patients with type 2 diabetes. Metformin was shown to have significant antidepressant effects; however, it is not clear whether metformin treatment improves outcomes in patients with type 2 diabetes who have concomitant depressive symptoms.

METHODS

A total of 475 patients with type 2 diabetes mellitus with depressive symptoms were included in this study and divided into metformin and nonmetformin groups according to whether they were taking metformin. The DASS-21 was used to assess patients' depression and anxiety scores before and after a 24-week intervention. In addition, general information about whether the patients had developed complications from diabetes and whether they had been diagnosed with other diseases was assessed.

RESULTS

(1) After 24 weeks, anxiety and depression scores were significantly lower in the metformin group than in the nonmetformin group. (2) The prevalence of depressive symptoms was significantly greater in female type 2 diabetic patients than in male patients (OR = 2.039, 95 % CI = 1.160-3.568). (3) People with type 2 diabetes who develop complications from diabetes (OR = 1.794, 95 % CI = 1.015-3.171) and those diagnosed with other conditions are more likely to experience depressive symptoms.

CONCLUSION

Metformin has an ameliorative effect on type 2 diabetes. However, women, those with diabetes complications, and those with type 2 diabetes who are also diagnosed with other conditions are more likely to experience depressive symptoms.

The interplay of gut microbiota, obesity, and depression: insights and interventions

The gut microbiome, body weight, and related comorbidities are intricately linked through a complex interaction of microbial, genetic, environmental, and psychological factors. Alterations in gut microbiota can contribute to the development of weight disorders and depressive symptoms, with the potential for these relationships to be bidirectional. Effective management of these interconnected conditions often involves a combination of lifestyle modifications and psychological support. Medical interventions, including treatments for obesity, antidiabetic drugs, antidepressants, antibiotics, and probiotics, can have beneficial and detrimental effects on gut microbiota and mental health. Further research is needed to better understand their impact on gut microbiome and mental health in the context of obesity.

The therapeutic potential of traditional Chinese medicine in depression: focused on the modulation of neuroplasticity

Depression, a mood disorder characterized by a persistent low mood and lack of enjoyment, is considered the leading cause of non-fatal health losses worldwide. Neuroplasticity refers to the brain's ability to adapt to external or internal stimuli, resulting in functional and structural changes. This process plays a crucial role in the development of depression. Traditional Chinese Medicine (TCM) shows significant potential as a complementary and alternative therapy for neurological diseases, including depression. However, there has been no systematic summary of the role of neuroplasticity in the pathological development of depression and TCM Interventions currently. This review systematically summarized recent literature on changes in neuroplasticity in depression and analyzed the regulatory mechanisms of active metabolites in TCM and TCM formulas on neuroplasticity in antidepressant treatment. Additionally, this review discussed the limitations of current research and the application prospects of TCM in regulating neuroplasticity in antidepressant research.

Metformin relieves bone cancer pain by reducing TGFβRI-TRPV1 signaling in rats

Common cancer complications include bone cancer pain (BCP), which was not sufficiently alleviated by traditional analgesics. More safe and effective therapy was urgent needed. Metformin relieved osteoarthritis pain, but the analgesia of Metformin in BCP was not well studied. The study aimed to explore the Metformin-mediated analgesic effect and its molecular mechanisms in BCP rats. We demonstrated that Walker 256 cell transplantation into the medullary cavity of the tibia worsened mechanical allodynia in BCP rats, increased the expression of TGFβ1 in the metastatic bone tissue, and raised the expression of TGFβRI and TRPV1 in the L4-6 dorsal root ganglion (DRG) of BCP rats. While, selectively blockade of TGFβRI by SD208 could obviously elevated the paw withdraw threshold (PWT) of BCP rats, together with decreased TRPV1 expression in L4-6 DRG. Notably, continuous Metformin treatment reduced TGFβ1, TGFβRI and TRPV1 expression, and relieved mechanical allodynia of BCP rats in a long-term effect. In conclusion, these results illustrated that Metformin ameliorated bone cancer pain, and the downregulation of TGFβ1-TGFβRI-TRPV1 might be a potential mechanism of Metformin-mediated analgesia in BCP.

Prevalence and risk factors of depression and anxiety in primary care

Introduction

Anxiety and depressive disorders are highly prevalent mental health conditions worldwide. However, little is known about their specific prevalence in primary care settings. This study aimed to determine the prevalence of depression and anxiety in the primary care population and identify associated patient characteristics.

Method

We conducted a cross-sectional study using stratified sampling by age with a self-administered questionnaire survey in Singapore's National Health-care Group Polyclinics from December 2021 to April 2022. A total score of Patient Health Questionnaire-9 (PHQ-9) ≥10 represents clinical depression, and a total score of Generalised Anxiety Disorder-7 (GAD-7) ≥10 indicates clinical anxiety. Multivariable logistic regression was used to identify the factors associated with depression and anxiety.

Results

A total of 5694 patients were approached and 3505 consented to the study (response rate=61.6%). There was a higher prevalence of coexisting clinical depression and anxiety (DA) (prevalence=5.4%) compared to clinical depression only (3.3%) and clinical anxiety only (1.9%). The odds of having DA were higher among those aged 21-39 years (odds ratio [OR] 13.49; 95% confidence interval [CI] 5.41-33.64) and 40-64 years (OR 2.28; 95% CI 1.03-5.03) compared to those ≥65 years. Women had higher odds of having DA (OR 2.33; 95% CI 1.54-3.50) compared to men. Respondents with diabetes had higher odds of having DA (OR 1.78; 95% CI 1.07-2.94) compared to those without diabetes.

Conclusion

Coexisting clinical depression and anxiety are significantly present in the primary care setting, especially among younger individuals, patients with diabetes and women. Mental health screening programmes should include screening for both depression and anxiety, and target these at-risk groups.

AMPK role in epilepsy: a promising therapeutic target?

Epilepsy is a complex and multifaceted neurological disorder characterized by spontaneous and recurring seizures. It poses significant therapeutic challenges due to its diverse etiology and often-refractory nature. This comprehensive review highlights the pivotal role of AMP-activated protein kinase (AMPK), a key metabolic regulator involved in cellular energy homeostasis, which may be a promising therapeutic target for epilepsy. Current therapeutic strategies such as antiseizure medication (ASMs) can alleviate seizures (up to 70%). However, 30% of epileptic patients may develop refractory epilepsy. Due to the complicated nature of refractory epilepsy, other treatment options such as ketogenic dieting, adjunctive therapy, and in limited cases, surgical interventions are employed. These therapy options are only suitable for a select group of patients and have limitations of their own. Current treatment options for epilepsy need to be improved. Emerging evidence underscores a potential association between impaired AMPK functionality in the brain and the onset of epilepsy, prompting an in-depth examination of AMPK's influence on neural excitability and ion channel regulation, both critical factors implicated in epileptic seizures. AMPK activation through agents such as metformin has shown promising antiepileptic effects in various preclinical and clinical settings. These effects are primarily mediated through the inhibition of the mTOR signaling pathway, activation of the AMPK-PI3K-c-Jun pathway, and stimulation of the PGC-1α pathway. Despite the potential of AMPK-targeted therapies, several aspects warrant further exploration, including the detailed mechanisms of AMPK's role in different brain regions, the impact of AMPK under various conditional circumstances such as neural injury and zinc toxicity, the long-term safety and efficacy of chronic metformin use in epilepsy treatment, and the potential benefits of combination therapy involving AMPK activators. Moreover, the efficacy of AMPK activators in refractory epilepsy remains an open question. This review sets the stage for further research with the aim of enhancing our understanding of the role of AMPK in epilepsy, potentially leading to the development of more effective, AMPK-targeted therapeutic strategies for this challenging and debilitating disorder.

Implication of lncRNA MSTRG.81401 in Hippocampal Pyroptosis Induced by P2X7 Receptor in Type 2 Diabetic Rats with Neuropathic Pain Combined with Depression

Major depressive disorder (MDD) is a common complication of diabetes and is often observed alongside diabetic neuropathic pain (DNP) as a comorbidity in diabetic patients. Long non-coding RNA (lncRNA) plays an important role in various pathophysiological processes. The P2X7 receptor is responsible for triggering inflammatory responses, such as pyroptosis, linked to pain and depression. The aim of this study was to investigate the effect of lncRNA MSTRG.81401 on hippocampal pyroptosis induced by the P2X7 receptor in diabetic rats with DNP combined with MDD (DNP + MDD). Our results showed that the expression of lncRNA MSTRG.81401 was significantly elevated in the hippocampus of DNP + MDD rats compared with the control group. Following the administration of shRNA targeting lncRNA MSTRG.81401, a notable elevation in mechanical and thermal pain thresholds was observed in rats with comorbid DNP and MDD. Additionally, significant improvements in depression-like behaviors were evident in the open-field test (OFT), sucrose preference test (SPT), and forced swim test (FST). In the DNP + MDD rats, elevated levels in hippocampal P2X7 receptor mRNA and protein were observed, along with increased co-expression of P2X7 and the astrocytic marker glial fibrillary acidic protein (GFAP). Meanwhile, in DNP + MDD rats, the heightened mRNA expression of NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), pyroptosis-related protein Gasdermin D (GSDMD), caspase-1, IL-1β, IL-18, and TNF-α was detected, in addition to increased serum levels of IL-1β, IL-18 and TNF-α. After shRNA treatment with lncRNA MSTRG.81401, the above abnormal changes in indicators for pyroptosis and inflammation were improved. Therefore, our study demonstrates that shRNA of lncRNA MSTRG.81401 can alleviate the pain and depression-like behaviors in diabetic rats associated with the comorbidity of DNP and MDD by inhibiting the hippocampal P2X7 receptor-mediated pyroptosis pathway and pro-inflammatory responses. This suggests that the P2X7R/NLRP3/caspase-1 implicated pyroptosis and inflammatory scenario may serve as a potential target for the management of comorbid DNP and MDD in diabetes.

Adult hippocampal neurogenesis: pharmacological mechanisms of antidepressant active ingredients in traditional Chinese medicine

Depression is characterized by prominent indicators and manifestations, such as anhedonia, which refers to the inability to experience pleasure, and persistent feelings of hopelessness. In clinical practice, the primary treatment approach involves the utilization of selective serotonin reuptake inhibitors (SSRIs) and related pharmacological interventions. Nevertheless, it is crucial to recognize that these agents are associated with significant adverse effects. Traditional Chinese medicine (TCM) adopts a multifaceted approach, targeting diverse components, multiple targets, and various channels of action. TCM has potential antidepressant effects. Anomalies in adult hippocampal neurogenesis (AHN) constitute a pivotal factor in the pathology of depression, with the regulation of AHN emerging as a potential key measure to intervene in the pathogenesis and progression of this condition. This comprehensive review presented an overview of the pharmacological mechanisms underlying the antidepressant effects of active ingredients found in TCM. Through examination of recent studies, we explored how these ingredients modulated AHN. Furthermore, we critically assessed the current limitations of research in this domain and proposed novel strategies for preclinical investigation and clinical applications in the treatment of depression in future.

Antidepressant pharmacological mechanisms: focusing on the regulation of autophagy

The core symptoms of depression are anhedonia and persistent hopelessness. Selective serotonin reuptake inhibitors (SSRIs) and their related medications are commonly used for clinical treatment, despite their significant adverse effects. Traditional Chinese medicine with its multiple targets, channels, and compounds, exhibit immense potential in treating depression. Autophagy, a vital process in depression pathology, has emerged as a promising target for intervention. This review summarized the pharmacological mechanisms of antidepressants by regulating autophagy. We presented insights from recent studies, discussed current research limitations, and proposed new strategies for basic research and their clinical application in depression.

Association of Metformin Use with Iron Deficiency Anemia in Urban Chinese Patients with Type 2 Diabetes

BACKGROUND

Previous evidence yielded contradictory findings on the relationship between metformin and anemia. This study aims to assess whether metformin use is associated with iron-deficiency anemia (IDA) risk in patients with type 2 diabetes (T2D) in Beijing, China.

METHODS

Overall, 60,327 newly diagnosed T2D patients were included based on a historical cohort study design. The information pertaining to these patients was gathered from the Beijing Medical Claim Data for Employees Database. These patients were then categorized into the metformin and non-metformin groups and matched on a 1:1 propensity score based on their initial antidiabetic prescription. The Cox proportional hazards models were utilized to calculate the incidences and the hazard ratios (HRs).

RESULTS

The study enrolled 27,960 patients with type 2 diabetes, with 13,980 patients in each of the initial glucose-lowering prescription groups: metformin and non-metformin. During a median follow-up period of 4.84 years, 4832 patients developed IDA. The incidence of IDA was significantly lower in the metformin group (26.08/1000 person-years) than in the non-metformin group (43.20/1000 person-years). Among the three groups divided by the proportion of days covered by metformin, we found a negative correlation between the proportion of days covered by metformin and the risk of IDA. The risk of IDA in patients with a proportion of days covered by metformin of <20%, 20-79%, and ≥80% was 0.43 (0.38, 0.48), 0.37 (0.34, 0.42), and 0.91 (0.85, 0.98), respectively, compared to the non-metformin group. We also performed subgroup analyses and sensitivity analyses: the incidence of IDA in the metformin group was lower than that in the non-metformin group in all subgroups, and the protective effect was more significant in subgroups of patients aged ≥65, with Charlson comorbidity index (CCI) ≥2, and with gastric acid inhibitor use.

CONCLUSIONS

In Chinese patients with T2DM, metformin treatment was associated with a decreased risk of IDA admission, and this risk responded positively to the proportion of days covered by metformin. These findings suggest that metformin may have a pleiotropic effect on IDA in patients with type 2 diabetes. Our study has important clinical implications for the management of patients with diabetes and other conditions that increase the risk of IDA.

Assessment of cognitive impairment and depressive signs in patients with type 2 diabetes treated with metformin from Southeast Mexico: A cross-sectional study

Multiple factors associate diabetes with cognitive impairment and depression. Antidiabetic drugs have reported antidepressant and pro-cognitive effects in diabetic and non-diabetic subjects. Antidepressant and pro-cognitive effects of metformin are reported in various studies; however, these effects are not consistent among researches. We designed a cross-sectional study. We recruited patients with T2D diagnosis from the Diabetes Clinic of the Regional Hospital of High Specialty "Dr. Gustavo A. Rovirosa Pérez" from January 2019 to May 2022. We included 431 subjects with T2D, 374 patients with metformin treatment and 57 subjects without metformin. These patients were on intensive therapies and had not a previous diagnosis of cognitive impairment or depression. We applied Mini-Mental State Examination (MMSE) to evaluate cognitive impairment, and Hamilton Depression Rating Scale (HAM-D) to assess depressive signs. Our sample had a mean age of 53.77 ± 13.43 years. Metformin users were 374 individuals, and 57 subjects didn't use metformin. MMSE found cognitive impairment in 8.3% (n = 31) of metformin users, and 14.8% (n = 8) of patients without metformin. HAM-D scale showed that 39.5% (n = 147) of patients with metformin had depression signs, subjects without metformin and depressive signs were 44.6% (n = 25). We found no differences between groups for cognitive impairment and depression grades. We did not find associations between metformin treatment, cognitive impairment measures and depression sign measures. However, chronic metformin treatment, insulin use, glycemic control and age could influence our results.