Impact of childhood trauma on positive and negative symptom remission in first episode psychosis

The role of metacognition and social cognition in childhood trauma effecting on prognosis: 1-year follow-up study in patients with first-episode schizophrenia

BACKGROUND

Childhood trauma (CT) is common in first episode schizophrenia (FES), affecting prognosis and functionality. However, the mechanisms by which CT effects prognosis are not clear. This study aimed to investigate how metacognition (MC) and social cognition (SC) mediate effects of CT on symptoms in FEP.

METHODS

52 first episode schizophrenia patients who were diagnosed for first time and had been symptomatic for at most 2 years were included. Patients were administered Metacognition Assessment Scale-Abbreviated to assess MC; Reading the Mind in the Eyes Test, Facial Emotion Recognition and Discrimination Tests to assess SC; Positive and Negative Syndrome Scale to assess psychopathology and Global Assessment of Functioning Scale to assess functionality at first interview. Patients were followed up for 1 year. At second interview the above scales and Childhood Trauma Questionnaire-33 were applied to 38 patients who met remission criteria.

RESULTS

MC and SC modulated effects of CT on negative symptoms, but not on positive symptoms. CT had different effects on symptoms, MC and SC skills in episode and remission. Pharmacological treatment was not sufficient to improve these skills.

CONCLUSIONS

MC and SC skills are important in modulating CT effecting on prognosis and non-pharmacological interventions should be developed to improve these skills.

CLINICAL TRIAL NUMBER

Not applicable.

Psychopathology trajectories and relapse in first episode schizophrenia with assured long-acting injectable adherence over 24 months

BACKGROUND

Relapse following a first episode of schizophrenia (FES) is common and often results in serious adverse psychosocial consequences. Treatment non-adherence is a key risk factor for relapse, but why relapse occurs despite antipsychotic treatment adherence remains unclear. This study examined the differences in FES psychopathology trajectories over 24-months with assured long-acting injectable antipsychotic (LAIA) treatment, to control for treatment adherence between those who relapsed and those who did not and what moderates these group differences.

METHODOLOGY

We collected clinical and socio-demographic data from 107 participants with FES treated with LAIA medication over a 24-month period. Relapse was defined using the modified Csernansky criteria. Substance use was assessed through participant and family interviews and urine toxicology. Linear mixed model repeated measures models were constructed to (1) compare psychopathology trajectories over 24 months between relapse versus non-relapse groups (2) to examine factors moderating differential trajectories between the groups.

RESULTS

Positive symptom trajectories were significantly worse in the relapse compared to non-relapse group over 24 months (F(8, 649 = 3.29), p = 0.001). More severe childhood trauma (CT), in particular physical abuse (PA) (F(39, 298 = 1.78), p = 0.004), was associated with worse positive symptom trajectories over 24 months in those who experienced a relapse event.

CONCLUSION

Our findings suggest that the examination of a history of CT and, in particular childhood PA measures for relapse in individuals with FES, is important.

Exploring the Interactions Between Psychotic Symptoms, Cognition, and Environmental Risk Factors: A Bayesian Analysis of Networks

BACKGROUND AND HYPOTHESIS

Psychotic disorders (PDs) have huge personal and societal impact, and efforts to improve outcomes in patients are continuously needed. Environmental risk factors (ERFs), especially modifiable risk factors, are important to study because they pose a target for intervention and prevention. No studies have investigated ERFs, cognition, and psychotic symptoms together in a network approach.

STUDY DESIGN

We explored interactions between 3 important ERFs (tobacco smoking, cannabis use, and childhood trauma), 6 cognitive domains, and 3 dimensions of symptoms in psychosis. From the Genetic Risk and Outcome of Psychosis (GROUP) cohort, we used data from patients, siblings, and healthy controls to construct networks using Bayesian analyses of all 12 variables. We constructed networks of the combined sample and of patients and siblings separately.

STUDY RESULTS

We found that tobacco smoking was directly associated with cognition and psychotic symptoms. The cognitive variable processing speed was the most central node, connecting clusters of psychotic symptoms and substance use through the variables of positive symptoms and tobacco smoking. Comparing the networks of patients and siblings, we found that networks were relatively similar between patients and siblings.

CONCLUSIONS

Our results support a potential central role of processing speed deficits in PDs. Findings highlight the importance of integrating tobacco smoking as potential ERFs in the context of PDs and to broaden the perspective from cannabis discontinuation to smoking cessation programs in patients or people at risk of PDs.

Childhood trauma and treatment resistance in first-episode psychosis: Investigating the role of premorbid adjustment and duration of untreated psychosis

BACKGROUND

Early identification of treatment non-response in first-episode psychosis (FEP) is essential to outcome. Despite indications that exposure to childhood trauma (CT) can have adverse effects on illness severity, its impact on treatment non-response and the interplay with other pre-treatment characteristics is sparsely investigated. We use a lack of clinical recovery as an early indicator of treatment resistance to investigate the relationship between CT and treatment resistance status at one-year follow-up and the potential mediation of this effect by other pre-treatment characteristics.

METHODS

This prospective one-year follow-up study involved 141 participants recruited in their first year of treatment for a schizophrenia-spectrum disorder. We investigated clinical status, childhood trauma (CT), premorbid adjustment (PA), and duration of untreated psychosis (DUP) at baseline and clinical status at one-year follow-up. Ordinal regression analyses were conducted to investigate how PA and DUP affected the relationship between CT and one-year outcome in FEP.

RESULTS

45 % of the FEP sample reported moderate to severe CT, with significantly higher levels of CT in the early treatment resistant group compared to participants with full or partial early recovery. Ordinal regression analysis showed that CT was a significant predictor of being in a more severe outcome group (OR = 4.59). There was a partial mediation effect of PA and a full mediation effect of DUP on the effect of CT on outcome group membership.

DISCUSSION

Our findings indicate that reducing treatment delays may mitigate the adverse effects of CT on clinical outcomes and support the inclusion of broad trauma assessment in FEP services.

Examining the psychobiological response to acute social stress across clinical stages and symptom trajectories in the early psychosis continuum

The stress-vulnerability model has been repeatedly highlighted in relation to the risk, onset and course of psychosis, and has been independently studied in clinical high-risk (CHR) and first-episode psychosis (FEP) populations. Notable in this literature, however, is that there are few studies directly comparing markers of stress response across progressive stages of illness. Here we examined the psychobiological response to the Trier Social Stress Test in 28 CHR (mean age 19.1) and 61 FEP (age 23.0) patients, in order to understand the stage(s) or trajectories in which differences in subjective stress or physiological response occur. The overall clinical sample had greater perceived stress and blunted cortisol (FEP + CHR, n = 89, age 21.7) compared with healthy controls (n = 45, age 22.9). Additional analyses demonstrated elevated heart rate and systolic blood pressure in FEP compared with CHR, but there were no further differences in physiological parameters (cortisol, heart rate, or blood pressure) between stage- or trajectory-based groups. Together, this suggests that individual stress response markers may differentially emerge at particular stages en route to psychosis - and demonstrates how stage-based analyses can shed light on the emergence and evolution of neurobiological changes in mental illness.

Linking childhood trauma to the psychopathology of schizophrenia: the role of oxytocin

Childhood trauma has been linked to schizophrenia, but underlying biological mechanisms remain elusive. This study explored the potential role of plasma oxytocin as a mediator in the relationship between childhood trauma and the psychopathology of schizophrenia. 160 patients with schizophrenia and 80 age- and sex-matched healthy controls were assessed for childhood trauma experiences using the Childhood Trauma Questionnaire and structured interviews. Psychopathology was evaluated using the Positive and Negative Syndrome Scale and plasma oxytocin levels were measured. Results showed that patients with schizophrenia had lower oxytocin levels and higher childhood trauma scores than healthy controls. There was a significant correlation between childhood trauma scores and psychopathology, with plasma oxytocin levels being inversely associated with psychopathology, except for positive symptoms. Hierarchical regression analysis indicated that both childhood trauma scores and plasma oxytocin levels significantly predicted psychopathology. Plasma oxytocin levels partially mediated the relationship between childhood trauma and schizophrenia psychopathology. This study underscores the potential role of oxytocin in bridging the gap between childhood trauma and schizophrenia.

Trauma and Trauma-Informed Care in Early Intervention in Psychosis: State of Implementation and Provider Views on Challenges

OBJECTIVE

Although trauma is increasingly recognized as a major risk factor for psychosis and for its link to treatment outcomes, the landscape of trauma-related practices in specialized early psychosis services in the United States and other countries remains only poorly characterized. Research documenting the perspectives of frontline providers is also lacking. The primary goals of this study were to document the state of trauma-related policy implementation in early intervention in psychosis (EIP) programs and to gather provider perspectives.

METHODS

This was a mixed-methods project involving an international EIP provider survey, followed by in-depth provider interviews. The survey was disseminated in Australia, Canada, Chile, the United Kingdom, and the United States. In total, 164 providers, representing 110 unique sites, completed the survey. Frequencies were calculated for responses to survey items, and open-ended responses were analyzed with a systematic content analysis.

RESULTS

The survey findings suggested low implementation rates for a variety of assessment and support practices related to trauma and trauma-informed care. Coding of open-ended responses revealed numerous concerns and uncertainties among providers regarding the relationship between trauma and psychosis and the state of the EIP field.

CONCLUSIONS

An expansion of research and service development aimed at better meeting the trauma-related needs of young people with psychosis is essential, with implications for EIP outcomes and service user and staff experiences.

How first-episode psychosis patients' subjective beliefs about their childhood trauma's causal effect provide support for potential schizophrenia subtypes

BACKGROUND

Childhood and adolescent trauma is a risk factor for developing psychosis-spectrum disorders. The current study aimed to assess how childhood trauma might predict psychosis symptomatology, and how patients' beliefs of whether trauma is the cause of psychosis might affect this association.

METHODS

Ninety-six first-episode psychosis patients were assessed for childhood traumatic experiences with the Brief Betrayal Trauma Survey, and for psychosis symptoms with the Positive and Negative Syndrome Scale.

RESULTS

Non-interpersonal trauma predicted higher positive symptoms, whereas more trauma domains experienced predicted lower negative symptoms. Almost half of the participants believed trauma to be related to psychosis, were 12 times more likely to reexperience trauma through psychosis, and had higher excitative and emotional symptoms. Non-interpersonal trauma also predicted higher positive symptoms in this group. Those who did not believe trauma to be the cause of psychosis had higher negative symptoms, and a negative dose-response was found for negative and disorganised symptoms, in which more trauma domains experienced predicted lower scores.

CONCLUSIONS

Results imply two traumagenic pathways to psychosis, one characterised by positive, excitative, and emotional symptoms, and one negative subtype, characterised by negative and disorganised symptoms. Clinical implications for how findings might contribute to better treatments are discussed.

Examining associations, moderators and mediators between childhood maltreatment, social functioning, and social cognition in psychotic disorders: a systematic review and meta-analysis

Childhood maltreatment (CM) has been related to social functioning and social cognition impairment in people with psychotic disorders (PD); however, evidence across different CM subtypes and social domains remains less clear. We conducted a systematic review and meta-analysis to quantify associations between CM, overall and its different subtypes (physical/emotional/sexual abuse, physical/emotional neglect), and domains of social functioning and social cognition in adults with PD. We also examined moderators and mediators of these associations. A PRISMA-compliant systematic search was performed on 24 November 2022 (PROSPERO CRD42020175244). Fifty-three studies (N = 13 635 individuals with PD) were included in qualitative synthesis, of which 51 studies (N = 13 260) with 125 effects sizes were pooled in meta-analyses. We found that CM was negatively associated with global social functioning and interpersonal relations, and positively associated with aggressive behaviour, but unrelated to independent living or occupational functioning. There was no meta-analytic evidence of associations between CM and social cognition. Meta-regression analyses did not identify any consistent moderation pattern. Narrative synthesis identified sex and timing of CM as potential moderators, and depressive symptoms and maladaptive personality traits as possible mediators between CM and social outcomes. Associations were of small magnitude and limited number of studies assessing CM subtypes and social cognition are available. Nevertheless, adults with PD are at risk of social functioning problems after CM exposure, an effect observed across multiple CM subtypes, social domains, diagnoses and illness stages. Maltreated adults with PD may thus benefit from trauma-related and psychosocial interventions targeting social relationships and functioning.

Association between exposome score for schizophrenia and functioning in first-episode psychosis: results from the Athens first-episode psychosis research study

BACKGROUND

Evidence suggests that environmental factors not only increase psychosis liability but also influence the prognosis and outcomes of psychotic disorders. We investigated temporal and cross-sectional associations of a weighted score of cumulative environmental liability for schizophrenia - the exposome score for schizophrenia (ES-SCZ) - with functioning in first-episode psychosis (FEP).

METHODS

Data were derived from the baseline and 1-month assessments of the Athens FEP Research Study that enrolled 225 individuals with FEP. The Global Assessment of Functioning (GAF) and the Personal and Social Performance Scale (PSP) were used to measure social, occupational, and psychological functioning. The ES-SCZ was calculated based on the previously validated method.

RESULTS

ES-SCZ was associated with the total scores of GAF and PSP at baseline and 1-month assessments. These findings remained significant when accounting for several associated alternative explanatory variables, including other environmental factors (obstetric complications, migration, ethnic minority), clinical characteristics (duration of untreated psychosis, symptom severity, previous antipsychotic use), and family history of psychosis, demonstrating that the association between ES-SCZ and functioning is over and above other risk factors and cannot be explained by symptom severity alone. Functioning improved from baseline to 1-month assessment, but no significant ES-SCZ-by-time interaction was found on functioning, indicating that functioning changes were not contingent on ES-SCZ.

CONCLUSIONS

Our findings suggest that rather than a predictor of functional improvement, ES-SCZ represents a stable severity indicator that captures poor functioning in early psychosis. Environmental risk loading for schizophrenia (ES-SCZ) can be beneficial for clinical characterization and incorporated into transdiagnostic staging models.

V. Hegelstad W, Joa I, Opjordsmoen SE, Rund BR, Røssberg JI, Simonsen E, Johannessen JO, Larsen TK, Haahr UH, McGlashan TH, Friis S, Melle I. Childhood trauma, antipsychotic medication, and symptom remission in first-episode psychosis

BACKGROUND

To what extent psychotic symptoms in first-episode psychosis (FEP) with a history of childhood interpersonal trauma (CIT) are less responsive to antipsychotic medication is not known. In this longitudinal study, we compare symptom trajectories and remission over the first 2 years of treatment in FEP with and without CIT and examine if differences are linked to the use of antipsychotics.

METHODS

FEP (N = 191) were recruited from in- and outpatient services 1997-2000, and assessed at baseline, 3 months, 1 and 2 years. Inclusion criteria were 15-65 years, actively psychotic with a DSM-IV diagnosis of psychotic disorder and no previous adequate treatment for psychosis. Antipsychotic medication is reported as defined daily dosage (DDD). CIT (<18) was assessed with the Brief Betrayal Trauma Survey, and symptomatic remission based on scores from the Positive and Negative Syndrome Scale.

RESULTS

CIT (n = 63, 33%) was not associated with symptomatic remission at 2 years follow-up (71% in remission, 14% in relapse), or time to first remission (CIT 12/ no-CIT 9 weeks, p = 0.51). Those with CIT had significantly more severe positive, depressive, and excited symptoms. FEP with physical (N = 39, 20%) or emotional abuse (N = 22, 14, 7%) had higher DDD at 1 year (p < 0.05). Mean DDD did not excerpt a significant between-group effect on symptom trajectories of positive symptoms.

CONCLUSION

Results indicate that antipsychotic medication is equally beneficial in the achievement of symptomatic remission in FEP after 2 years independent of CIT. Still, FEP patients with CIT had more severe positive, depressive, and excited symptoms throughout.

Sensory gating deficits and childhood trauma in the onset of first-episode schizophrenia

BACKGROUND

Studies have shown sensory gating deficits and severe childhood trauma in patients with schizophrenia; however, their relationship with this condition remains unclear. Here, we hypothesized that sensory gating deficits mediate the effects of childhood trauma on schizophrenia onset.

METHODS

We recruited 79 patients with first-episode schizophrenia (PFES) and 76 health controls (HC). The auditory conditioning (S1) and testing (S2) stimulus paradigm was used to detect P50 sensory gating. The Childhood Trauma Questionnaire (CTQ) was used to assess childhood trauma experiences.

RESULTS

Compared with HC, the PFES group had more severe childhood trauma experiences together with sensory gating deficits. In a partial correlation analysis, sexual abuse was negatively correlated with the P50 S2 latency, physical neglect was negatively correlated with the S1 latency, while emotional neglect was positively correlated with the S2/S1 ratio and negatively correlated with the S1-S2 difference in the PFES group. However, there was no correlation between the CTQ total and each sub-scores and P50 indicators in the HC. The S1-S2 difference was the mediator between emotional neglect and the onset of schizophrenia.

CONCLUSION

Childhood trauma might be associated with schizophrenia by influencing sensory gating deficits. Early intervention targeting childhood trauma might reduce the incidence of sensory gating deficits and thus schizophrenia.

Rumination mediates the relationship between childhood trauma and depressive symptoms in schizophrenia patients

Rumination and childhood trauma are related to depressive symptoms in clinical and non-clinical individuals. This is the first study aimed to test the mediating effect of rumination on the relationship between childhood trauma and depressive symptoms in schizophrenia patients. A total of 313 schizophrenia patients were recruited in the present study. The 17-item Hamilton Depression Rating Scale (HAMD-17) was adopted to evaluate depressive symptoms, the short-form Childhood Trauma Questionnaire (CTQ-SF) and the 10-item Ruminative response scale (RRS-10) were utilized to assess the childhood trauma and rumination in patients, respectively. Our results showed that 168 schizophrenia patients (53.67%) had comorbid depressive symptoms. These patients with depressive symptoms had higher levels of childhood trauma [both CTQ-SF total scores and emotional abuse (EA), emotional neglect (EN), physical neglect (PN) subscale scores] and rumination (both RRS-10 total scores and brooding, reflection subscale scores) compared to patients without depressive symptoms. The stepwise logistic regression analysis identified that EN (OR 1.196, P = 0.003), PN (OR 1.1294, P < 0.001), brooding (OR 1.291, P < 0.001) and reflection (OR 1.481, P < 0.001) could independently predict the depressive symptoms in schizophrenia patients. Moreover, RRS-10 and its subscale scores could mediate the relationship between depressive symptoms and childhood trauma, especially EA, EN and PN in schizophrenia. Our preliminary findings suggest that the rigorous assessment and psychosocial interventions of rumination are important to alleviate the influence of childhood trauma on depressive symptoms in schizophrenia patients.

Trauma and psychosis: The mediating role of premorbid adjustment and recent stressful events in a 3-year longitudinal study

BACKGROUND

Some of the most-studied environmental factors that can contribute to the development of psychosis are the adversities experienced at an early age. Among these, childhood interpersonal trauma (CIT) has been considered especially influential in the onset of the disease. The aim of the study was to explore the relationship between CIT and the first episode of psychosis (FEP), as well as the relationship between CIT and clinical and functional outcomes 3 years after illness onset.

METHODS

A total of 278 patients with a FEP and 52 healthy controls were studied. Logistic regression analysis was carried out to examine the explained variation by CIT at the beginning of psychosis. Recent stressful events and premorbid adjustment related to CIT, were introduced in path analyses to determine their mediating effects between CIT and the disease and its clinical and functional results.

RESULTS

Mediation analyses showed that CIT was indirectly associated with belonging to the FEP group through recent stressful events (Effect = 0.981; SE = 0.323; CI = 0.485 to 1.761). Premorbid academic adjustment in late adolescence mediated the relationship between CIT and clinical and functional outcomes, specifically in the measurements of the Scales for Assessment of Positive and Negative Symptoms, in the Brief Psychiatric Rating Scale, and in the Disability Assessment Scale.

CONCLUSIONS

These findings suggest that early traumatic experiences play an important role in the FEP. Early intervention that promotes good academic adjustment during adolescence and/or avoids retraumatisation could positively impact both the onset and the course of psychotic illness.

Risk factors of deficit and non-deficit schizophrenia: Results from a cross-sectional study

AIM

It has been observed that deficit and non-deficit schizophrenia (SCZ-D and SCZ-ND) might be characterized by different risk factors. Therefore, the present study aimed to assess as to whether previously reported risk factors of schizophrenia are specifically associated with SCZ-D and SCZ-ND.

METHOD

This study was based on a cohort of 118 stable outpatients with schizophrenia. A diagnosis of SCZ-D was established using the Schedule for the Deficit Syndrome (SDS). Risk factors were recorded using structured interview, the Operational Criteria for Psychotic Illness (OPCRIT) checklist and the Traumatic Experience Checklist (TEC). The following risk factors were explored: male sex, a history of schizophrenia in first-degree relatives, seasonality of birth, birth weight <3000g, delivery by cesarean section, a history of childhood trauma (emotional abuse, emotional neglect, physical abuse and sexual abuse) as well as substance abuse (other than nicotine) and cigarette smoking at psychosis onset.

RESULTS

Individuals with SCZ-D were more likely to be males as well as reported higher rates of birth weight <3000g and any categories of childhood trauma. In turn, substance abuse (other than nicotine) at psychosis onset was significantly more frequent in patients with SCZ-ND. Binary logistic regression, controlling for multiple comparisons, revealed similar findings, except for the association with any categories of childhood trauma that appeared to be not significant.

CONCLUSION

Our findings partially replicate differential patterns of risk factors for SCZ-D (male sex and birth weight <3000g) and SCZ-ND (substance abuse at psychosis onset), likely attributable to the effects of timing of exposure.

The effects of childhood adversity on treatment delays and its components in first-episode psychosis

Apart from increasing risk for psychotic disorders, childhood adversity has been associated with worse outcomes. One way in which childhood adversity may worsen outcomes is by lengthening treatment delays, which are associated with negative impacts. We tested the influence of childhood trauma on treatment delays, measured as the duration of untreated psychosis (DUP), and its help-seeking and referral components, in a first-episode psychosis cohort (N = 203). We accounted for pertinent social (e.g., migrant status) and other determinants (i.e., age at onset, diagnosis, symptoms) of treatment delays. Multiple linear regression analyses revealed that for a one-unit increase in Childhood Trauma Questionnaire (CTQ) scores, average overall DUP increased by 25%. Higher CTQ scores also significantly predicted help-seeking and referral DUPs. Patients with schizophrenia-spectrum psychosis had longer help-seeking and total DUPs than those with affective psychosis. More severe positive symptoms predicted longer help-seeking DUPs, while more severe negative symptoms predicted longer referral DUPs. Indicators of social disadvantage did not affect DUP. Our results show that childhood trauma increases DUP by prolonging the help-seeking process and delaying access to mental healthcare even after help is sought. Early identification of psychosis among populations with trauma histories seems warranted and can likely positively impact outcomes.

A meta-analysis of blood and salivary cortisol levels in first-episode psychosis and high-risk individuals

Dysregulated cortisol responses and glucose metabolism have been reported in psychosis. We performed a random-effects meta-analysis of cortisol responses in first-episode psychosis (FEP) and psychosis risk states, taking into consideration glucose metabolism. A total of 47 studies were included. Unstimulated blood cortisol levels were significantly higher (g = 0.48, 95 %CI: 0.25-0.70, p < 0.001) in FEP, but not in psychosis risk states (g = 0.39, 95 %CI: -0.42-1.21, p = 0.342), compared to controls. Cortisol awakening response (CAR) was attenuated in FEP (g = -0.40, 95 %CI: -0.68 - -0.12, p = 0.006), but not in psychosis risk states (p = 0.433). Glucose and insulin levels were positively correlated with unstimulated blood cortisol levels in FEP. Our meta-analysis supports previous findings of elevated blood cortisol levels and attenuated CAR in FEP. Future research should focus on identifying the common denominators for alterations in stress hormones and glucose metabolism.

Childhood maltreatment and social functioning in psychotic disorders: a systematic review protocol

Background: Childhood maltreatment (CM) is thought to play a key role in the etiology and course of psychotic disorders (PD). In addition, CM is related to neurobiological and clinical characteristics that can lead to poor social functioning. However, the extent to which CM and social functioning are directly associated in individuals with PD, is unclear. Therefore, we aim to systematically review the literature to provide an estimate on the strength of the association between CM and different domains of social functioning in PD and to summarize potential moderators and mediators of this association.Methods and analysis: To identify relevant studies, we will systematically search the following databases: Pubmed (Medline), PsycInfo, Embase, Web of Science (Core Collection), and Pilots (trauma), manually search reference lists and contact experts in the field. Studies will be included if they investigate and report on the association between CM (exposure) and social functioning (outcome) in adults with PD. Two independent reviewers will screen titles, abstracts and full texts according to eligibility criteria, perform data extraction and assess study quality according to a modified version of the Newcastle-Ottawa Scale.Analysis: Effect estimates will be pooled in a meta-analysis. Heterogeneity and publication bias will be assessed and the effects of potential moderators (genetic factors, type of diagnosis, duration of illness, type of CM and age at the time of CM exposure) will be analyzed using meta-regressions. Candidate moderators and mediators (neurocognition, cognitive schemas, comorbidities, stress sensitivity, attachment) will be also examined qualitatively.Ethics and dissemination: Because this review will make use of already published data, ethical approval will not be sought. This work has the potential to inform upcoming investigations on the association between the exposure to CM in PD and social functioning. PROSPERO registration number CRD42020175244.