ObjectiveTo investigate the mechanisms by which Bushen Tongluo Jiangzhuo prescription improves renal fibrosis in rats with chronic kidney disease （CKD） through the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway. MethodsSeventy specific pathogen-free （SPF） Sprague-Dawley （SD） rats were randomly divided into a control group （n=15） and a modeling group （n=55）. Rats in the modeling group were administered a 2.5% adenine suspension at a dose of 200 mg·kg^-1·d^-1 by gavage for 4 weeks to establish a CKD model. Successfully modeled rats were randomly divided into a model group， an irbesartan group （20.25 mg·kg^-1·d^-1）， and Bushen Tongluo Jiangzhuo prescription low-， medium-， and high-dose groups （5.82， 11.64， and 23.28 g·kg^-1·d^-1， respectively）， with 10 rats in each group. Each group was administered an equal volume of physiological saline， the corresponding concentration of irbesartan， or Bushen Tongluo Jiangzhuo prescription by gavage for 12 weeks. Body weight and renal function indices were dynamically monitored. Serum creatinine （SCr）， blood urea nitrogen （BUN）， urine albumin-to-creatinine ratio （ACR）， 24-hour urinary total protein （24 hUTP）， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， interleukin-1β （IL-1β）， interleukin-6 （IL-6）， and tumor necrosis factor-α （TNF-α） levels were measured using an automatic biochemical analyzer. Renal histopathological changes were observed by hematoxylin-eosin （HE） and Masson staining. Immunohistochemistry （IHC） was used to detect the expression of PI3K， Akt， phosphorylated Akt （p-Akt）， and mTOR in renal tissues. Western blot was performed to assess the protein expression of PI3K， p-Akt， Akt， phosphorylated mTOR （p-mTOR）， and mTOR in renal tissues. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to determine the mRNA expression levels of PI3K， Akt， and mTOR in renal tissues. ResultsCompared with the model group， rats in the irbesartan group and the low-， medium-， and high-dose Bushen Tongluo Jiangzhuo prescription groups showed significantly decreased levels of SCr， BUN， ACR， 24 hUTP， IL-1β， IL-6， and TNF-α （P<0.01）. AST levels were significantly increased （P<0.01）， while no significant difference was observed in ALT levels. Histopathological examination revealed that， compared with the model group， renal tubular epithelial cell edema and necrosis and Bowman's capsule dilation were alleviated， inflammatory cell infiltration was reduced， and interstitial and glomerular fibrosis was markedly improved in all treatment groups， with the most pronounced effect observed in the high-dose Bushen Tongluo Jiangzhuo prescription group. Real-time PCR results showed that mRNA expression levels of PI3K， Akt， and mTOR were significantly downregulated in the high-dose group （P<0.01）. IHC results demonstrated that PI3K and p-Akt expression levels in renal tissues were significantly decreased in the high-dose group （P<0.01）. Western blot analysis further confirmed that the expression levels of PI3K， p-Akt/Akt， and p-mTOR/mTOR were significantly reduced in the high-dose group （P<0.01）. ConclusionBushen Tongluo Jiangzhuo prescription improves renal function indices in CKD rats， reduces collagen deposition in renal tissues， and decreases serum inflammatory factor levels. Its protective effect on renal function may be achieved by activating autophagy through downregulation of the PI3K/Akt/mTOR signaling pathway， thereby alleviating renal fibrosis.

ObjectiveTo investigate the molecular mechanism by which the Bushen Kaixuan Tongluo prescription exerts a renal protective effect in mice with diabetic kidney disease （DKD） by regulating the cyclic adenosine monophosphate （cAMP） signaling pathway. MethodsThirty specific pathogen-free （SPF） male db/db mice were adaptively fed for three weeks. Mice with a random tail vein blood glucose level ≥ 11.1 mmol·L^-1 and urinary albumin-creatinine ratio （ACR） ≥ 30 mg·g^-1 were considered successfully modeled. The successfully modeled mice were randomly divided into five groups with six mice in each group： the model group， the low-， medium-， and high-dose Bushen Kaixuan Tongluo prescription groups （administered at doses of 7， 14， 28 g·kg^-1·d^-1 respectively）， and the positive drug irbesartan group （administered at a dose of 20 mg·kg^-1·d^-1）. Additionally， six db/m mice were selected as the blank group. Mice in each group were given intragastric administration of the Bushen Kaixuan Tongluo prescription at the corresponding concentrations， irbesartan， or an equal volume of pure water， and the intervention lasted for 12 weeks. During the experiment， the general conditions， body weight changes， and renal function indicators of the mice were dynamically monitored. After the intervention， a blood glucose meter was used to measure the fasting blood glucose （FBG） of the mice. An automatic biochemical analyzer was employed to detect the levels of serum creatinine （SCr）， blood urea nitrogen （BUN）， urinary microalbumin （uALB）， ACR， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， total cholesterol （TC）， triglycerides （TG）， leptin （LEP）， glycosylated serum protein （GSP）， and insulin （INS） in the mice. Renal tissues were collected for hematoxylin-eosin （HE） staining， periodic acid-Schiff （PAS） staining， and Masson's trichrome staining to observe the histopathological changes. Immunohistochemistry （IHC） was used to detect the expressions of protein kinase A （PKA） and cAMP response element-binding protein （CREB） in the mice. Western blot analysis was performed to determine the expression levels of PKA， phosphorylated protein kinase A （p-PKA）， CREB， phosphorylated cAMP response element-binding protein （p-CREB）， and B-cell lymphoma-2 （Bcl-2） proteins in the renal tissues of the mice. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression levels of PKA， CREB， and Bcl-2 in the renal tissues of the mice. ResultsCompared with the blank group， the mice in the model group showed listlessness， decreased activity， and a significant increase in body weight （P<0.01）. Biochemical indicators revealed that the levels of BUN， uALB， ACR， AST， ALT， TC， TG， FBG， LEP， GSP， and INS were significantly increased （P<0.01）， while SCr showed an increasing trend with no statistically significant difference. Compared with the model group， the mice in the Bushen Kaixuan Tongluo prescription intervention groups had improved general conditions and a decreasing trend in body weight. Biochemical indicators showed that the levels of BUN， uALB， ACR， TC， GSP， and INS were significantly decreased （P<0.05）， while SCr， AST， ALT， TG， and LEP showed a decreasing trend with no statistically significant difference. Renal histopathological analysis showed that the model group exhibited typical DKD pathological features such as thickening of the glomerular basement membrane， expansion of the mesangial matrix， and deposition of collagen fibers in the renal tubulointerstitium， and all treatment groups could alleviate the above pathological damages. The IHC results showed that compared with the blank group， the expression levels of p-PKA and p-CREB in the renal tissues of the model group were significantly decreased （P<0.01）. Compared with the model group， the expression level of p-PKA in the medium-dose Bushen Kaixuan Tongluo prescription group was significantly increased （P<0.01）， while the expression level of p-CREB showed an increasing trend with no statistically significant difference. Western blot results showed that compared with the blank group， the expression levels of p-PKA/PKA， p-CREB/CREB， and Bcl-2 in the model group were significantly decreased （P<0.05）. Compared with the model group， the expression levels of these proteins in the medium-dose Bushen Kaixuan Tongluo prescription group were significantly increased （P<0.01）. Real-time PCR results showed that compared with the blank group， the mRNA expressions of PKA， CREB， and Bcl-2 in the model group were significantly down-regulated （P<0.05）. Compared with the model group， the mRNA expressions of these genes in the medium-dose Bushen Kaixuan Tongluo prescription group were significantly up-regulated （P<0.05）. ConclusionThe Bushen Kaixuan Tongluo prescription can improve the liver and kidney functions of db/db mice， correct lipid metabolism disorders and glucose metabolism imbalance. Its renal protective effect is associated with up-regulating the cAMP signaling pathway to improve renal fibrosis and reduce the level of oxidative stress， thereby protecting renal function.

(rsFC)and their relationship with negative symptoms in schizophrenia patients with predominant negative symptoms(PNS).Methods Fifty-four schizophrenia patients with PNS and sixty-one healthy controls underwent resting-state functional magnetic resonance imaging(fMRI)scans.Data were collected on general demographic information,the Positive and Negative Syndrome Scale(PANSS),the Scale for the Assessment of Negative Symptoms(SANS),and the Temporal Experience of Pleasure Scale(TEPS).Twelve striatal subregions were selected as regions of interest(ROIs)to analyze the rsFC between each ROI and whole-brain voxels.The rsFC values of areas with significant differences were extracted for Pearson correlation analysis with negative symptoms.Results Compared with healthy controls,schizophrenia patients with PNS exhibited decreased rsFC between the right dorsal caudal putamen(DCP)and right insula,left middle frontal gyrus(MFG),right median cingulate and paracingulate gyri(MCC);between the left DCP and right putamen,left insula,left MFG;between the right dorsal rostral putamen(DRP)and bilateral MFG,left insula,right MCC;between the left DRP and right insula,left rolandic operculum;between the right ventral rostral putamen(VRP)and bilateral putamen,left MFG,right MCC;between the left VRP and right insula,left putamen,bilateral MFG,right MCC,left inferior parietal gyrus,excluding supramarginal and angular gyri.Decreased rsFC was also observed between the left ventral caudate/nucleus accumbens(inferior)and right insula,left anterior cingulate cortex,supracallosal,bilateral precuneus(a threshold of P<0.001 in voxel-level with P<0.05 in cluster-lever,corrected for family-wise error,PFWE<0.05/12=0.004).No regions showed increased rsFC in schizophrenia patients with PNS relative to healthy controls.And no significant correlations were found between striatal rsFC and negative symptoms(PBonferroni>0.05).Conclusion Schizophrenia patients with PNS exhibited widespread cortical-striatal functional connectivity abnormalities,particularly reduced rsFC between the putamen and the MFG,MCC and insula.

Objective:To develop and validate a prediction model for medication adherence among patients receiving allergen sublingual immunotherapy (SLIT).Methods:A prospective cross-sectional study was conducted, and a total of 288 patients who received SLIT treatment at an allergy center in the First Affiliated Hospital with Nanjing Medical University (Jiangsu Province Hospital) from December 2023 to July 2024 were assigned to the modeling group. Additionally, 122 patients from August to October 2024 were assigned to the validation group. Data of patients′ general information, medication beliefs, anxiety levels, social support, disease perception, and medication adherence were collected. Single-factor analysis and LASSO regression were utilized to identify potential predictors, and a prediction model for medication adherence was constructed using multifactorial logistic regression. A nomogram was then developed based on the model. The model′s discriminatory ability was evaluated using receiver operating characteristic curve (ROC), the area under curve (AUC), sensitivity, and specificity. The model was then validated in the validation cohort.Results:Single-factor analysis and LASSO regression identified a total of nine predictive factors. Logistic regression revealed that medical belief tendency [ OR (95% CI) =2.420 (1.116-5.248), P=0.025], the somatic control dimension in self-rating anxiety scales [ OR (95% CI)=1.404 (1.241-1.589), P<0.001], the subjective support dimension in social support assessment [ OR (95% CI)=0.784 (0.725-0.847), P<0.001], and the cognitive dimension in illness perception [ OR (95% CI)=0.725 (0.647-0.813), P<0.001] were independent predictors of medication adherence in patients undergoing SLIT. The AUC value of the model was 0.899 (95% CI=0.863-0.934) in the modeling group and 0.882 (95% CI=0.820-0.944) in the validation group, indicating good discriminatory ability. The optimal cutoff value of the model was 0.493, with a sensitivity of 81.1% and specificity of 85.7% in the modeling group, and a sensitivity of 87.3% and specificity of 82.5% in the validation group. Conclusion:The medication adherence prediction model developed in this study for patients undergoing SLIT exhibits good predictive performance and provides valuable guidance for early intervention by clinical healthcare professionals.

Objective:To explore effect of Astragalus polysaccharides(APS)through TLR4/NF-κB signal pathway on intesti-nal immune inflammation of rats with dampness stagnancy due to spleen deficiency syndrome based on fecal microbiota transplantation.Methods:Rats with dampness stagnancy due to spleen deficiency syndrome were fed with high-fat and low-protein diet and subjected to exhaustive swimming,transplant flora microbiota after intervention of APS.General condition,changes in weight gain,time of weight exhaustion swimming,spleen index and thymus index were tested.Pathological manifestations of duodenal tissue inflammation were observed by HE staining.Serum IL-1β,IL-6 and TNF-α concentrations of rats were determined by ELISA.Protein levels of TLR4,NF-κB p65 and IκBα in colon were determined by Western blot.Results:Compared with model group,general condition rating,changes in weight gain and time of weight exhaustion swimming in APS-FTG group were increased significantly(P<0.01);spleen index and thymus index were increased;pathological manifestations of duodenal inflammation were significantly relieved;serum IL-1β,IL-6 and TNF-α concentrations were decreased significantly(P<0.01),TLR4 and NF-κB p65 levels in colon were decreased significantly(P<0.05 and P<0.01),IκBα level was in colon increased significantly(P<0.01).Conclusion:APS improves intestinal microbiota of rats with dampness stagnancy due to spleen deficiency syndrome and inhibits TLR4/NF-κB pathway activation through intestinal flora,thus improving intestinal immune inflammation status in rats with dampness stagnancy due to spleen deficiency syndrome.

ObjectiveTo investigate the mechanism of Tangbikang dry paste in the prevention and treatment of type 2 diabetic peripheral neuropathy （DPN） based on the glyoxalase-1 （GLO-1）/advanced glycation end products （AGE）/receptor for advanced glycation end products （RAGE） pathway. MethodsA total of 56 Sprague-Dawley rats were randomly divided， with eight assigned to the normal group. The remaining 48 rats were fed a high-fat diet combined with intraperitoneal injection of streptozotocin （STZ） to induce a type 2 diabetes mellitus （T2DM） model. Based on blood glucose levels， the rats were randomly assigned to the model group， Tanglin group （13.5 mg·kg^-1）， metformin group （135 mg·kg^-1）， and Tangbikang dry paste low-， medium-， and high-dose groups （3， 6， 12 g·kg^-1）. Successful modeling of DPN was confirmed by a decrease in mechanical pain threshold in the model group at week 4. Fasting blood glucose， body weight， and mechanical pain threshold were measured every 4 weeks. After 16 weeks of intervention， the pathological morphology of the sciatic nerve was observed using hematoxylin-eosin （HE） staining. The expression of RAGE， AGE， protein kinase C （PKC）， and collagen （COL） in the sciatic nerve was assessed by immunohistochemistry. The mRNA expression of RAGE， PKC， Toll-like receptor （TLR）， COL， and GLO-1 was detected using real-time quantitative PCR （Real-time PCR）. Serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， creatinine （CREA）， urea （UREA）， interleukin-6 （IL-6）， and tumor necrosis factor （TNF）-α were measured by enzyme-linked immunosorbent assay （ELISA）. ResultsCompared with the normal group， the model group showed significantly increased fasting blood glucose （P<0.01）， decreased body weight and mechanical pain threshold （P<0.01）， and elevated serum AST， ALT， CREA， UREA， IL-6， and TNF-α levels （P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was significantly increased （P<0.01）， while COL expression was decreased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was upregulated （P<0.01）， whereas COL and GLO-1 mRNA levels were downregulated （P<0.01）. Histological examination showed irregular nerve morphology， axonal alterations， and myelin degeneration. Compared with the model group， fasting blood glucose levels in the Tangbikang dry paste high-dose group at all time points and in the medium-dose group at weeks 4 and 16 were significantly reduced （P<0.05， P<0.01）. No significant changes in body weight were observed across all Tangbikang dose groups. The mechanical pain threshold was elevated at different time points after administration in all Tangbikang groups （P<0.05， P<0.01）. Serum IL-6 and TNF-α levels were decreased in all dose groups （P<0.05， P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was reduced （P<0.01）， while COL expression was increased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was downregulated （P<0.01）， whereas GLO-1 mRNA expression was upregulated （P<0.05， P<0.01）. Additionally， COL mRNA expression was significantly increased in the low- and high-dose groups （P<0.01）. Pathological changes in the sciatic nerve were milder in all Tangbikang groups compared to the model group. ConclusionTangbikang dry paste significantly improves DPN， and its mechanism may be associated with the regulation of the GLO-1/AGE/RAGE signaling pathway.

Diabetic nephropathy （DN） is a renal disorder induced by prolonged hyperglycemia， with major pathological features including persistent albuminuria， progressive decline in glomerular filtration rate， and elevated arterial blood pressure. As one of the most common and severe microvascular complications of diabetes， the pathogenesis of DN is complex and multifactorial. Without timely and effective treatment， DN may eventually progress to end-stage renal disease （ESRD）. Currently available therapeutic options are often associated with significant adverse effects and high costs， and a large number of patients still progress to ESRD due to delayed treatment. Therefore， there is an urgent need for safer and more effective treatment strategies to improve the living standards and enhance the survival and quality of life of patients with DN. Modern studies have demonstrated that the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway plays a critical role in oxidative stress， inflammatory responses， autophagy， and glycolysis， and is closely associated with the pathophysiological progression of DN. In recent years， traditional Chinese medicine （TCM） has achieved remarkable progress in the prevention and treatment of DN， supported by rich clinical experience and confirmed therapeutic efficacy. With its characteristics of multi-target， multi-component， and multi-pathway actions， along with minimal side effects， TCM can delay the progression of DN and alleviate patient symptoms. Among these mechanisms， the regulation of the PI3K/Akt signaling pathway has gradually become a research hotspot. This paper systematically reviews the role and mechanisms of the PI3K/Akt signaling pathway in the onset and progression of DN based on extensive literature research， summarizes the latest research advances on the precise modulation of the PI3K/Akt pathway by Chinese medicine monomers， active constituents， Chinese patent medicines， and herbal compound formulas in the treatment of DN， aiming to provide a strong theoretical reference for the development of clinically effective agents for DN prevention and treatment.

ObjectiveTo investigate the mechanism of Tangbikang dry paste in the prevention and treatment of type 2 diabetic peripheral neuropathy （DPN） based on the glyoxalase-1 （GLO-1）/advanced glycation end products （AGE）/receptor for advanced glycation end products （RAGE） pathway. MethodsA total of 56 Sprague-Dawley rats were randomly divided， with eight assigned to the normal group. The remaining 48 rats were fed a high-fat diet combined with intraperitoneal injection of streptozotocin （STZ） to induce a type 2 diabetes mellitus （T2DM） model. Based on blood glucose levels， the rats were randomly assigned to the model group， Tanglin group （13.5 mg·kg^-1）， metformin group （135 mg·kg^-1）， and Tangbikang dry paste low-， medium-， and high-dose groups （3， 6， 12 g·kg^-1）. Successful modeling of DPN was confirmed by a decrease in mechanical pain threshold in the model group at week 4. Fasting blood glucose， body weight， and mechanical pain threshold were measured every 4 weeks. After 16 weeks of intervention， the pathological morphology of the sciatic nerve was observed using hematoxylin-eosin （HE） staining. The expression of RAGE， AGE， protein kinase C （PKC）， and collagen （COL） in the sciatic nerve was assessed by immunohistochemistry. The mRNA expression of RAGE， PKC， Toll-like receptor （TLR）， COL， and GLO-1 was detected using real-time quantitative PCR （Real-time PCR）. Serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， creatinine （CREA）， urea （UREA）， interleukin-6 （IL-6）， and tumor necrosis factor （TNF）-α were measured by enzyme-linked immunosorbent assay （ELISA）. ResultsCompared with the normal group， the model group showed significantly increased fasting blood glucose （P<0.01）， decreased body weight and mechanical pain threshold （P<0.01）， and elevated serum AST， ALT， CREA， UREA， IL-6， and TNF-α levels （P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was significantly increased （P<0.01）， while COL expression was decreased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was upregulated （P<0.01）， whereas COL and GLO-1 mRNA levels were downregulated （P<0.01）. Histological examination showed irregular nerve morphology， axonal alterations， and myelin degeneration. Compared with the model group， fasting blood glucose levels in the Tangbikang dry paste high-dose group at all time points and in the medium-dose group at weeks 4 and 16 were significantly reduced （P<0.05， P<0.01）. No significant changes in body weight were observed across all Tangbikang dose groups. The mechanical pain threshold was elevated at different time points after administration in all Tangbikang groups （P<0.05， P<0.01）. Serum IL-6 and TNF-α levels were decreased in all dose groups （P<0.05， P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was reduced （P<0.01）， while COL expression was increased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was downregulated （P<0.01）， whereas GLO-1 mRNA expression was upregulated （P<0.05， P<0.01）. Additionally， COL mRNA expression was significantly increased in the low- and high-dose groups （P<0.01）. Pathological changes in the sciatic nerve were milder in all Tangbikang groups compared to the model group. ConclusionTangbikang dry paste significantly improves DPN， and its mechanism may be associated with the regulation of the GLO-1/AGE/RAGE signaling pathway.

Diabetic nephropathy （DN） is a renal disorder induced by prolonged hyperglycemia， with major pathological features including persistent albuminuria， progressive decline in glomerular filtration rate， and elevated arterial blood pressure. As one of the most common and severe microvascular complications of diabetes， the pathogenesis of DN is complex and multifactorial. Without timely and effective treatment， DN may eventually progress to end-stage renal disease （ESRD）. Currently available therapeutic options are often associated with significant adverse effects and high costs， and a large number of patients still progress to ESRD due to delayed treatment. Therefore， there is an urgent need for safer and more effective treatment strategies to improve the living standards and enhance the survival and quality of life of patients with DN. Modern studies have demonstrated that the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway plays a critical role in oxidative stress， inflammatory responses， autophagy， and glycolysis， and is closely associated with the pathophysiological progression of DN. In recent years， traditional Chinese medicine （TCM） has achieved remarkable progress in the prevention and treatment of DN， supported by rich clinical experience and confirmed therapeutic efficacy. With its characteristics of multi-target， multi-component， and multi-pathway actions， along with minimal side effects， TCM can delay the progression of DN and alleviate patient symptoms. Among these mechanisms， the regulation of the PI3K/Akt signaling pathway has gradually become a research hotspot. This paper systematically reviews the role and mechanisms of the PI3K/Akt signaling pathway in the onset and progression of DN based on extensive literature research， summarizes the latest research advances on the precise modulation of the PI3K/Akt pathway by Chinese medicine monomers， active constituents， Chinese patent medicines， and herbal compound formulas in the treatment of DN， aiming to provide a strong theoretical reference for the development of clinically effective agents for DN prevention and treatment.

Depression is a prevalent mental and emotional disor-der that often results in significant emotional disturbances,cog-nitive dysfunction,and memory impairments.It is characterized by a high incidence rate,a substantial disability burden,and limited therapeutic efficacy.Currently,the long-term use of medications for the treatment of depression can result in a range of adverse reactions,highlighting the urgent need to explore no-vel approaches that can effectively alleviate depressive symptoms while minimizing side effects.Curcumin,a natural polyphenolic compound derived from the rhizome of turmeric,demonstrates considerable potential in the prevention and treatment of depres-sion,owing to its diverse array of biological activities.In recent years,numerous studies have investigated the use of curcumin for the treatment of depression.This article aims to provide a comprehensive review of the mechanisms of action underlying curcumin's efficacy in treating depression.Specifically,it focu-ses on its ability to improve neurotransmitter imbalances,restore neural plasticity,alleviate neural damage,mitigate dysfunction of the hypothalamic-pituitary-adrenal(HPA)axis,regulate in-flammatory factors and neuroinflammatory signaling pathways,and inhibit oxidative stress.This review is intended to offer in-sights and methodological references for basic research on curcu-min,as well as for the development of novel therapeutic agents for the treatment of depression.