Relationship between the lesion location of acute ischemic stroke and early depressive symptoms in Japanese patients

Analysis of radiological features in patients with post-stroke depression and cognitive impairment

Post-stroke depression (PSD) and post-stroke cognitive impairment (PSCI) are common complications following a stroke, significantly impacting the quality of life and survival time of survivors. Currently, the comorbidity of PSCI and PSD is receiving increasing attention, as they share some common clinical characteristics, mechanisms, risk factors, radiological features, and treatment strategies. They influence each other, with the clinical prevalence of PSD comorbid with PSCI reaching as high as 26.15 %. The prevention, screening, diagnosis, and treatment of PSD and PSCI require collaboration across clinical, radiological, and neuropsychological evaluations. This paper aims to summarize the common radiological features of both conditions from a radiological perspective, which may aid in identifying early screening and predictive imaging biomarkers.

Upregulation of S100A8 in peripheral blood mononuclear cells from patients with depression treated with SSRIs: a pilot study

BACKGROUND

Major depressive disorder (MDD) affects more than 350 million people worldwide, and there is currently no laboratory test to diagnose it. This pilot study aimed to identify potential biomarkers in peripheral blood mononuclear cells (PBMCs) from MDD patients.

METHODS

We used tandem mass tagging coupled to synchronous precursor selection (mass spectrometry) to obtain the differential proteomic profile from a pool of PBMCs from MDD patients and healthy subjects, and quantitative PCR to assess gene expression of differentially expressed proteins (DEPs) of our interest.

RESULTS

We identified 247 proteins, of which 133 had a fold change ≥ 2.0 compared to healthy volunteers. Using pathway enrichment analysis, we found that some processes, such as platelet degranulation, coagulation, and the inflammatory response, are perturbed in MDD patients. The gene-disease association analysis showed that molecular alterations in PBMCs from MDD patients are associated with cerebral ischemia, vascular disease, thrombosis, acute coronary syndrome, and myocardial ischemia, in addition to other conditions such as inflammation and diabetic retinopathy.

CONCLUSIONS

We confirmed by qRT-PCR that S100A8 is upregulated in PBMCs from MDD patients and thus could be an emerging biomarker of this disorder. This report lays the groundwork for future studies in a broader and more diverse population and contributes to a deeper characterization of MDD.

Large-scale lesion symptom mapping of depression identifies brain regions for risk and resilience

Understanding neural circuits that support mood is a central goal of affective neuroscience, and improved understanding of the anatomy could inform more targeted interventions in mood disorders. Lesion studies provide a method of inferring the anatomical sites causally related to specific functions, including mood. Here, we performed a large-scale study evaluating the location of acquired, focal brain lesions in relation to symptoms of depression. Five hundred and twenty-six individuals participated in the study across two sites (356 male, average age 52.4 ± 14.5 years). Each subject had a focal brain lesion identified on structural imaging and an assessment of depression using the Beck Depression Inventory-II, both obtained in the chronic period post-lesion (>3 months). Multivariate lesion-symptom mapping was performed to identify lesion sites associated with higher or lower depression symptom burden, which we refer to as 'risk' versus 'resilience' regions. The brain networks and white matter tracts associated with peak regional findings were identified using functional and structural lesion network mapping, respectively. Lesion-symptom mapping identified brain regions significantly associated with both higher and lower depression severity (r = 0.11; P = 0.01). Peak 'risk' regions include the bilateral anterior insula, bilateral dorsolateral prefrontal cortex and left dorsomedial prefrontal cortex. Functional lesion network mapping demonstrated that these 'risk' regions localized to nodes of the salience network. Peak 'resilience' regions include the right orbitofrontal cortex, right medial prefrontal cortex and right inferolateral temporal cortex, nodes of the default mode network. Structural lesion network mapping implicated dorsal prefrontal white matter tracts as 'risk' tracts and ventral prefrontal white matter tracts as 'resilience' tracts, although the structural lesion network mapping findings did not survive correction for multiple comparisons. Taken together, these results demonstrate that lesions to specific nodes of the salience network and default mode network are associated with greater risk versus resiliency for depression symptoms in the setting of focal brain lesions.

In-Hospital Symptoms of Depression and Anxiety are Strong Risk Factors for Post-Stroke Depression 90 Days After Ischemic Stroke

Background and Purpose

Acute ischemic stroke (AIS) and depression are the major causes of disability and decreased quality of life worldwide. Psychiatric disorders are common after stroke, especially post-stroke depression (PSD), which affects one-third of survivors. Although frequent, little is known about the real complexity of the pathophysiology and the factors associated with PSD.

Methods

This research aimed to provide data about risk factors and predictors of PSD 90 days after AIS. A cohort study was conducted in a tertiary stroke center located in southern Brazil. We interviewed 148 patients with AIS who were consecutively hospitalized between January 2020 and January 2021. The Hospital Anxiety and Depression Scale (HADS) was applied during hospitalization and at follow-up 90 days after AIS. Furthermore, sociodemographic, clinical, and radiological variables were investigated. Predictive factors were assessed using univariate and multivariate linear regression. The impact of the COVID-19 pandemic on the data was also evaluated.

Results

The frequency of PSD 90 days after AIS was 33.9%. In-hospital symptoms of depression and anxiety each represented a 2-fold risk for PSD at follow-up. Furthermore, the HADS - anxiety score 90 days after AIS was strongly associated with the HADS - depression value 90 days after stroke (R: .71; B: .56; P < .01).

Conclusions

The present study highlighted a noteworthy frequency of PSD 90 days after AIS. Psychiatric variables during hospitalization and in the follow-up appeared to be the leading associated factors with PSD. These data might support the determination of which patients require more psychiatric management.

Social isolation in patients with chronic limb-threatening ischemia: a cross-sectional study

Assistance by family members or friends plays important roles in the course of treating patients with chronic limb-threatening ischemia (CLTI), both during hospitalization and after discharge. The aim of this study was to reveal the prevalence of social isolation and to explore relevant clinical backgrounds in patients with CLTI presenting with tissue loss and requiring revascularization. We analyzed 413 patients registered in a multicenter study in whom revascularization were scheduled for CLTI with tissue loss. Social isolation was analyzed by assessing the residence status of the patients and the involvement of a trusted family member or friend in their daily lives and during hospitalization. Patients living alone accounted for 24.5% (95% confidence interval [CI] 20.1-28.8%) of the study population. Patients receiving welfare were more likely to live alone (P < 0.001). For patients living alone, 21.8% (95% CI 12.8-30.8%) met a trusted family member or friend in their daily lives less than once per year. Younger age and receiving welfare were independently associated with lower frequency of meeting the trusted person in their daily lives (both P < 0.05). The adjusted odds ratio of age and receiving welfare was 0.44 (95% CI 0.29-0.67) per 10-year increase and 3.47 (95% CI 1.43-8.44), respectively. During hospitalization, 9.9% (95% CI 6.8-13.0%) of the patients had no hospital visits by a trusted family member or friend on three key occasions: the patient's first hospital visit, the preoperative explanation regarding the planned operation, and the day of the operation. Younger age and receiving welfare were independently associated with lower frequency of hospital visits by a family member or friend (both P < 0.05). The adjusted odds ratio of age and receiving welfare for no visit versus ≥ 1 visit was 0.51 (0.36-0.74) per 10-year increase and 5.29 (2.46-11.4), respectively. In conclusion, social isolation is common among patients with CLTI, especially younger patients and those on welfare. Practical countermeasures against social isolation are warranted in the management of CLTI.

A Comparative Study of Regional Cerebral Blood Flow Asymmetry Index in Stroke Patients with or without Poststroke Depression Using 99m Tc-ECD Single-Photon Emission Computed Tomography

Introduction  Stroke is a major cause of death and disability around the globe. The development of depression following a stroke further increases the disability and impairs functional recovery. In recent decades, despite the advancement in structural and nuclear medicine imaging, the pathophysiologic basis of poststroke depression (PSD) is not well understood. Etiopathogenesis of PSD is multifactorial and afflictions of the frontal lobe, hippocampus, limbic region, and basal ganglia projections are implicated. Aim  The aim of this study was to assess the regional cerebral blood flow (rCBF) using 99m Tc-ethyl cysteinate dimer single-photon emission computed tomography (SPECT) in patients with (PSD + ) or without PSD (PSD-). Materials and Methods  To evaluate the hemispheric asymmetry, the percentage of asymmetry index (AI) was calculated for frontal, temporal, parietal, occipital, putamen, caudate, and thalamic regions of brain and compared between PSD+ and PSD-. The correlation between AIs over the different brain regions was also established in patients of PSD+ and PSD-. Our study cohort included 122 patients between 6 weeks and 1 year of stroke. Depression was present in 52 (42.6%) patients, assessed by hospital anxiety and depression scale (HADS) and general health questionnaire-28 items (GHQ-28) scale. The 28 patients with PSD+ and 18 PSD- gave consent for SPECT study. Results  Our results are based on 46 patients who underwent SPECT study. In patients with PSD+ and PSD-, the HADS and GHQ-28 scores were 8.93 ± 2.77 vs. 3.94 ± 2.15 ( p  = 0.001) and 40.96 ± 9.48 vs. 17.72 ± 5.38 ( p  = 0.001), respectively. A significant difference in rCBF AI was found in the temporal lobe ( p  = 0.03) between patients of PSD+ and PSD-. On logistic regression analysis, the odds ratio of rCBF AI for temporal lobe was 0.89 (95% confidence interval [CI]: 0.80-0.99; p  = 0.04) and caudate nucleus was 0.85 (95% CI: 0.73-0.98; p  = 0.03), which were statistically significant. PSD correlated with AI in temporal region ( r  = -0.03; p  = 0.03) but did not show significant correlation with other regions of brain between PSD+ and PSD-. Conclusion  The presence of temporal lobe rCBF AI on SPECT is significantly associated with PSD. This may reflect the dysfunction of the limbic system and contribute to the occurrence of PSD.

Depressive symptoms due to stroke are strongly predicted by the volume and location of the cerebral infarction, white matter hyperintensities, hypertension, and age: A precision nomothetic psychiatry analysis

OBJECTIVES

To delineate the effects of white matter hyperintensities (WMHs) as measured by Fluid-attenuated inversion recovery (FLAIR) and infarction volume as measured by Diffusion-weighted imaging (DWI) on post-stroke depression symptoms.

METHODS

Baseline National Institutes of Health Stroke Score (NIHSS) and Modified Rankin Scale (mRS) scores, and FLAIR and DWI MRIs to assess WMHs and acute infarct volumes, respectively, were assessed in 47 patients (≥55 years) with acute ischemic stroke and 17 normal controls. The Montgomery-Åsberg Depression Rating Scale (MDRS) was assessed three months after the stroke.

RESULTS

The MADRS score was significantly increased in stroke patients as compared with normal controls. The MADRS scale is not unidimensional and cannot be used as an accurate indicator of depression severity in stroke patients. Three months after stroke, key depressive (sadness and inability to feel) and concentration-tension symptoms, and lassitude are significantly predicted by the infarct volume. Right side infarction strongly predicts key depressive symptoms and left side infarction strongly predicts concentration-tension and lassitude scores. Total WMHs significantly predict key depressive and concentration-tension symptoms, and lassitude, with these effects being mediated by right and left DWI stroke volumes and associated disabilities.

CONCLUSIONS

Interactions between age, hypertension, a chronic atherosclerotic process, and acute stroke account for the onset of key depressive symptoms three months after the acute infarct. Chronic and acute neuro-immune and neuro-oxidative stress pathways associated with the formation of WMHs and acute stroke may explain the incidence of post-stroke key depressive and concentration-tension symptoms, and lassitude.

Understanding Why Post-Stroke Depression May Be the Norm Rather Than the Exception: The Anatomical and Neuroinflammatory Correlates of Post-Stroke Depression

Ischemic Stroke precedes depression. Post-stroke depression (PSD) is a major driver for poor recovery, negative quality of life, poor rehabilitation outcomes and poor functional ability. In this systematic review, we analysed the inflammatory basis of post-stroke depression, which involves bioenergetic failure, deranged iron homeostasis (calcium influx, Na influx, potassium efflux etc), excitotoxicity, acidotoxicity, disruption of the blood brain barrier, cytokine-mediated cytotoxicity, reactive oxygen mediated toxicity, activation of cyclooxygenase pathway and generation of toxic products. This process subsequently results in cell death, maladapted, persistent neuro-inflammation and deranged neuronal networks in mood-related brain regions. Furthermore, an in-depth review likewise reveals that anatomic structures related to post-stroke depression may be localized to complex circuitries involving the cortical and subcortical regions.

Symptom clusters of early-stage poststroke depression: A mixed-methods study

Aim

To identify the symptom clusters of early‐stage poststroke depression (PSD) and provide an in‐depth understanding of the symptoms.

Design

A mixed‐methods study with a convenient sampling method was used.

Methods

A cross‐sectional questionnaire survey in 231 stroke patients and semi‐structured interviews in 14 stroke patients were conducted in the neurological department of a comprehensive hospital in Southeast China. Data from the questionnaire survey were analysed through descriptive and exploratory factor analyses; data from the semi‐structured interview were transcribed verbatim and analysed through inductive content analysis. This study adheres to the GRAMMS checklist.

Results

Exploratory factor analysis revealed six symptom clusters of early‐stage PSD that accounted for an ideal variance in PSD: nervous, wakefulness, emotional, dull, guilt and low mood. Further, inductive content analysis revealed five themes that were like the above symptom clusters, except for the dull symptom cluster.

Association of Cerebral Artery Stenosis With Post-stroke Depression at Discharge and 3 Months After Ischemic Stroke Onset

Background: Post-stroke depression (PSD) is one of the most common complications after stroke, which seriously affects patients' recovery outcome. Although vascular depression has been extensively studied, the relationship between cerebral artery stenosis and PSD has not been clarified so far. Methods: Two hundred ninety-eight patients with ischemic stroke (72 women, 226 men) with computed tomography angiography (CTA) or magnetic resonance angiography (MRA) were included in this study. Cerebral artery stenosis ≥50% was used as the cut-off value. The DSM-V diagnostic criteria of PSD was met and the 17-item Hamilton Rating Scale for Depression (HAMD-17) score over 7 at discharge and 3 months after stroke onset was regarded as the primary outcome. The χ²-test, Mann-Whitney U-test, and t-test were used to check for statistical significance. Results: At discharge, Barthel index (p < 0.001), left middle cerebral artery stenosis (p = 0.019), drinking history (p = 0.048), basilar artery stenosis (p = 0.037) were significantly associated with PSD. At 3 months after ischemic stroke onset, Barthel index (p = 0.011), left middle cerebral artery stenosis (p = 0.012), female gender (p = 0.001) were significantly associated with PSD. Conclusions: The findings demonstrated that left middle cerebral artery and basilar artery stenosis are associated with PSD. It was suggested that cerebral artery stenosis was a risk factor of PSD and should be recognized and intervened early. Registration Number: ChiCTR-ROC-17013993.

Post-Stroke Depression

Introduction:

The depression is a common mental disorder, especially after a stroke, which further aggravates the recovery.

Aim:

To analyze depression within 48 hours and fifteen days after ischemic stroke in relation to gender and location (brain hemisphere and brain circulation).

Methods:

We analyzed 40 patients (65.3±10.3 years), half of them were women. Mean age of women was 66.35±7.31 years and men 64.2±12.68 years (p= 0.5). Ischemic stroke was verified by computed tomography. Levels of depression were measured with self-estimated Zung’s scale. On the tests, score of 50 and higher verified depression. Criteria made by Domasio were used to determine location of the IS.

Results:

Mean value on depression scale in acute phase of ischemic stroke was 46.85 ± 8.6 and in subacute phase 43.4 ± 8 (p =0.06). In 19 (47.5%) patients (55% of women, 40% of men; p=0.3) depression was found during the first and in 10 (25%) patients (35% of women, 15 % of men; p=0.06) during the second evaluation (p<0.019). Mean value on depression in acute phase of illness in women was 49.1 ± 7.38, as well as in men 44.6 ± 9.22 (p=0.088) and in subacute phase in women 45.25 ± 8.04, as well as in men 41.5 ± 7.75 (p=0.16). Concerning location of ischemic stroke, there were no significant differences in levels of depression.

Conclusion:

Number of patients with post-stroke depression is significantly lower in subacute phase of ischemic stroke. Although the number of depressive women and their depression scores are higher, gender differences are not statistically significant. There is no correlation between post-stroke depression and location of lesion in acute and subacute phase of illness.

The association between mean platelet volume levels and poststroke depression

OBJECTIVE

High levels of mean platelet volume (MPV) had been found in depression subjects. We sought to examine the relationship between MPV and poststroke depression (PSD).

METHODS

One hundred and eighty-five patients with acute ischemic stroke were enrolled in our study. Peripheral venous blood samples were drawn at admission and MPV levels were measured by the automated hematology analyzer. Patients with a HAMD-17 score >7 were diagnosed as having PSD.

RESULTS

We found that 60 patients (32.4%) developed PSD, the MPV levels in PSD patients were significantly higher (9.3 ± 1.8 fl) compared to non-PSD patients (8.5 ± 1.6 fl). High MPV levels (≥9.1 fl) were independently correlated with PSD (OR 2.762, 95% CI 1.138-6.702, p = 0.025).

CONCLUSIONS

Patients with higher levels of MPV at admission were correlated with the development of PSD at 1 month after stroke and might be a predictor of its presence.

Changes in motor function, cognition, and emotion-related behavior after right hemispheric intracerebral hemorrhage in various brain regions of mouse

Intracerebral hemorrhage (ICH) is a detrimental type of stroke. Mouse models of ICH, induced by collagenase or blood infusion, commonly target striatum, but not other brain sites such as ventricular system, cortex, and hippocampus. Few studies have systemically investigated brain damage and neurobehavioral deficits that develop in animal models of ICH in these areas of the right hemisphere. Therefore, we evaluated the brain damage and neurobehavioral dysfunction associated with right hemispheric ICH in ventricle, cortex, hippocampus, and striatum. The ICH model was induced by autologous whole blood or collagenase VII-S (0.075 units in 0.5 µl saline) injection. At different time points after ICH induction, mice were assessed for brain tissue damage and neurobehavioral deficits. Sham control mice were used for comparison. We found that ICH location influenced features of brain damage, microglia/macrophage activation, and behavioral deficits. Furthermore, the 24-point neurologic deficit scoring system was most sensitive for evaluating locomotor abnormalities in all four models, especially on days 1, 3, and 7 post-ICH. The wire-hanging test was useful for evaluating locomotor abnormalities in models of striatal, intraventricular, and cortical ICH. The cylinder test identified locomotor abnormalities only in the striatal ICH model. The novel object recognition test was effective for evaluating recognition memory dysfunction in all models except for striatal ICH. The tail suspension test, forced swim test, and sucrose preference test were effective for evaluating emotional abnormality in all four models but did not correlate with severity of brain damage. These results will help to inform future preclinical studies of ICH outcomes.

Lower cognitive control network connectivity in stroke participants with depressive features

Around one-third of people develop depression following ischaemic stroke, yet the underlying mechanisms are poorly understood. Post-stroke depression has been linked to frontal infarcts, mainly lesions in the left dorsolateral prefrontal cortex (DLPFC). But depression is a network disorder that cannot be fully characterised through lesion-symptom mapping. Researchers of depression in non-stroke populations have successfully tapped into the cognitive control network (CCN) using the bilateral DLPFC as a seed, and found that CCN resting-state connectivity is reduced in even mildly depressed subjects, compared to healthy controls. Hence, we aimed to investigate the association between post-stroke depressive features and the CCN resting-state connectivity in a stroke population. We analysed DLPFC resting-state connectivity in 64 stroke participants, 20 of whom showed depressive features assessed with the Patient Health Questionnaire (PHQ-9) at 3 months after stroke. We directly compared groups showing symptoms of depression with those who did not, and performed a regression with PHQ-9 scores in all participants, controlling for age, gender, lesion volume and stroke severity. Post-stroke depression was associated with lower connectivity between the left DLPFC and the right supramarginal gyrus (SMG) in both group and regression analyses. Neither the seed nor the results overlapped with stroke lesions. These findings confirm an important role of the left DLPFC in post-stroke depression, but now show that large-scale network disruptions following stroke associated with depressive features occur without lesions in the DLPFC.

The association between lesion location, sex and poststroke depression: Meta-analysis

BACKGROUND

Poststroke depression (PSD) is a common form of stroke patients. Whether the risk of PSD is influenced by the stroke lesion location and sex remains a matter of debate. The objective of this study was to examine the association between the risk of PSD and the stroke lesion location and sex by performing a systematic meta-analysis.

METHODS

Subgroup analyses were performed according to the time interval after stroke onset to assessment for PSD. A total of 31 reports involving 5,309 subjects (for lesion location analysis) and 5,489 subjects (for sex analysis) suffering from stroke were included in this meta-analysis.

RESULTS

The pooled odds ratio (OR) of PSD after a left-hemisphere stroke, compared with a right-hemisphere stroke was 1.11 (95% confidence interval [CI] 0.82-1.49) and OR of PSD after a male stroke, compared with a female stroke was 0.68 (95% CI 0.58-0.81). Subacute poststroke subgroup (1-6 months) significantly favored PSD occurring after a left hemisphere stroke (OR = 1.50, 95% CI 1.21-1.87). Furthermore, there was a statistically significant association between PSD and female stroke for studies with acute poststroke group (OR = 0.73, 95% CI 0.62-0.86) and subacute poststroke stroke phase (OR = 0.69, 95% CI 0.56-0.86).

CONCLUSIONS

This systematic review suggests that patients with left hemisphere stroke may be more susceptible to PSD during subacute phase of stroke and female stroke may be more susceptible to PSD during acute and subacute phase of stroke.

Post-Stroke Depression: Impact of Lesion Location and Methodological Limitations-A Topical Review

Post-stroke depression (PSD) affects approximately one-third of all stroke patients. It hinders rehabilitation and is associated with worse functional outcome and increased mortality. Since the identification of PSD is a significant clinical problem, clinicians and researchers have tried to identify predictors that indicate patients at risk of developing PSD. This also includes the research question whether there is an association between PSD and stroke lesion characteristics, e.g., lesion size and lesion location. Early studies addressing this question are largely limited by technical constraints and, thus, focused on simple lesion characteristics such as lesion side or proximity of the lesion to the frontal pole of the brain. More recent studies have addressed the impact of involvement of specific neuronal circuits in the stroke lesion. State-of-the-art methods of lesion symptom mapping to study PSD have only been applied to small patient samples. Overall, results are controversial and no clear pattern of stroke lesions associated with PSD has emerged, though there are findings suggesting that more frontal stroke lesions are associated with higher incidence of PSD. Available studies are hampered by methodological limitations, including drawbacks of lesion analysis methods, small sample size, and the issue of patient selection. These limitations together with differences in approaches to assess PSD and in methods of image analysis limit the comparability of results from different studies. To summarize, as of today no definite association between lesion location and PSD can be ascertained and the understanding of PSD rests incomplete. Further insights are expected from the use of modern lesion inference analysis methods in larger patient samples taking into account standardized assessment of possible confounding parameters, such as stroke treatment and reperfusion status.

Imaging Markers of Post-Stroke Depression and Apathy: a Systematic Review and Meta-Analysis

Several brain imaging markers have been studied in the development of post-stroke depression (PSD) and post-stroke apathy (PSA), but inconsistent associations have been reported. This systematic review and meta-analysis aims to provide a comprehensive and up-to-date evaluation of imaging markers associated with PSD and PSA. Databases (Medline, Embase, PsycINFO, CINAHL, and Cochrane Database of Systematic Reviews) were searched from inception to July 21, 2016. Observational studies describing imaging markers of PSD and PSA were included. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated to examine the association between PSD or PSA and stroke lesion laterality, type, and location, also stratified by study phase (acute, post-acute, chronic). Other imaging markers were reviewed qualitatively. The search retrieved 4502 studies, of which 149 studies were included in the review and 86 studies in the meta-analyses. PSD in the post-acute stroke phase was significantly associated with frontal (OR 1.72, 95% CI 1.34–2.19) and basal ganglia lesions (OR 2.25, 95% CI 1.33–3.84). Hemorrhagic stroke related to higher odds for PSA in the acute phase (OR 2.58, 95% CI 1.18–5.65), whereas ischemic stroke related to higher odds for PSA in the post-acute phase (OR 0.20, 95% CI 0.06–0.69). Frequency of PSD and PSA is modestly associated with stroke type and location and is dependent on stroke phase. These findings have to be taken into consideration for stroke rehabilitation programs, as this could prevent stroke patients from developing PSD and PSA, resulting in better clinical outcome.

Risk Factors for Post-stroke Depression: A Meta-analysis

Background: Stroke not only impacts patients physically but also economically. Post-stroke depression (PSD), as a common complication of stroke, always obstructs the process of stroke rehabilitation. Accordingly, defining the risk factors associated with PSD has extraordinary importance. Although there have been many studies investigating the risk factors for PSD, the results are inconsistent.

Objectives: The objectives of this study were to identify the risk factors for PSD by evidence-based medicine.

Data sources: A systematic and comprehensive database search was performed of PubMed, Medline, CENTRAL, EMBASE.com, the Cochrane library and Web of Science for Literature, covering publications from January 1, 1998 to November 19, 2016.

Study Selection: Studies on risk factors for PSD were identified, according to inclusion and exclusion criteria. The risk of bias tool, described in the Cochrane Handbook version 5.1.0, was used to assess the quality of each study. Meta-analysis was performed using RevMan 5.3 software.

Results: Thirty-six studies were included for review. A history of mental illness was the highest ranking modifiable risk factor; other risk factors for PSD were female gender, age (<70 years), neuroticism, family history, severity of stroke, and level of handicap. Social support was a protective factor for PSD.

Conclusion: There are many factors that have effects on PSD. The severity of stroke is an important factor in the occurrence of PSD. Mental history is a possible predictor of PSD. Prevention of PSD requires social and family participation.