Introduction
Paranoid personality disorder (PPD) is a disordered pattern of thinking characterized by persistent suspicion and distrust of others [1]. Paranoid ideation has been defined by Freeman and Garety [2 ] as follows: “The individual believes that harm is occurring, or is going to occur, to him or her and that the persecutor has the intention to cause harm”. Paranoid ideation ranges from mild mistrust and doubt to complete delusions [3]. Although the prevalence of PPD is estimated at 5% according to the DSM-5 criteria [4], paranoid ideation is common in the general population [5], which raises challenges and questions about the factors that contribute to clinical or severe paranoia [6]. Studies have shown that paranoid ideation has serious psychological consequences [7-9]. It can also be considered as a response to the perception of interpersonal threats [10].
Early life experiences have a broad long-term effect on behavioral and psychological development [9]. Early life negative experiences are one of the risk factors for psychological disorders such as anxiety and depression, destructive behaviors, antisocial behaviors and substance abuse [11], psychosis [12], suicidal behaviors [13], hallucinations, and suicidal thoughts [14]. Early life experiences are related to paranoid ideation [15-17].
Interpersonal threats play an important role in creating a feeling of shame, which is one of the negative emotions [18]. Shame is associated with depression, suicidal ideation, anxiety, paranoia, post-traumatic stress disorder, eating disorders, and personality disorders [19, 20]. Shame is related to paranoid ideation [17, 21, 22] and early life experiences [24, 25].
Self-criticism is related to persecutory delusions [26], paranoid ideation [27], and early life experiences [28]. In a study, Carvalho et al. [21] investigated the role of self-criticism, early emotional memories, and shame in adolescents’ paranoid ideation. Their findings showed that shame, self-criticism, and early emotional memories explained 26-48% of paranoid ideation, especially in severe forms. 
Understanding paranoid ideation in non-clinical populations is necessary to reduce interpersonal and social conflicts caused by such beliefs and to reduce vulnerability to psychopathology/psychosocial problems. Considering the complex and multidimensional nature of early life experiences and Paranoia ideation, it seems that the relationship between these two variables is not linear and direct, and some variables intervene in the relationship between them. Considering the role of shame and self-criticism, perhaps they play a mediating role in this relationship. This study aimed to investigate the mediating role of shame and self-criticism in the relationship between early life experiences and paranoid ideation in college students.

Methods
This is a correlational study using structural equation modeling (SEM). The study population consists of all students of Ahvaz Jundishapur University of Medical Sciences in Ahvaz, Iran, in 2021-2022. Determining the minimum sample size is important in structural equation modeling. Of these, 272 students were selected by a convenience sampling method. The data collection tools included the Paranoid Thoughts Scale-8 (GPTS-8), the Early Life Experiences Scale (ELES), the External and Internal Shame Scale (EISS), and the Forms of Self-Criticizing/Attacking & Self-Reassuring Scale - Short Form (FSCRS-SF).
The GPTS-8 is a standard scale to measure paranoid thoughts developed by Green et al. [36]. It is an eight-item scale with a five-point Likert scale from 1 (not at all) to 5 (totally). It has a single-factor structure with very good psychometric properties [36]. The ELES is a 15-item scale developed by Gilbert [37] to examine the importance and value of evaluating personal behaviors and emotional experiences from childhood. Subjects answer the items based on a Likert scale from 1 (completely false) to 5 (completely true). This scale has favorable psychometric properties [31]. The EISS has 8 items measuring internal and external shame, scored on a five-point Likert scale from 0 (never) to 4 (always). This scale has favorable psychometric properties [32]. The FSCRS-SF is a 14-item self-report instrument that assesses how people think and react in the face of failure and shortcomings. The items are scored based on a five-point Likert scale from 0 (not at all like me) to 4 (extremely like me). This scale has favorable psychometric properties [33]. For data analysis, the Pearson correlation test was conducted in SPSS Software version 24, and the SEM was used in LISREL software, version 8.80. The bootstrap test was used to evaluate the effects of mediators.

Results
The mean age of participants was 24.4±3.70 years, ranging 18-40 years. They included 97 males (35.7%) and 175 females (64.3%). The results of the independent t-test showed no significant difference between males and females in paranoid ideation (P>0.05). The results in Table 1 showed that paranoid ideation had a positive and significant relationship with shame (r=0.56, P=0.01), self-criticism (r=0.31, P=0.01), and early life experiences (r=0.51, P=0.01). The indirect relationship between early life experiences and paranoid ideation was also significant through shame, with a standard path coefficient of 0.25 (P<0.05). However, indirect relationship between early life experiences and paranoid ideation through self-criticism was not significant (P>0.05)



Conclusion
Based on the results, it can be concluded that early experiences in childhood cause shame and self-criticism, which is associated with the emergence of paranoid thoughts. In our study, shame and self-criticism mediated the relationship between early life experiences and paranoid ideation in Iranian college students. Therefore, the variables of shame and self-criticism can be considered in developing therapeutic interventions for people with paranoid thoughts. Further research should be conducted to examine the development of paranoid thoughts in youth across the lifespan,  compare at-risk general populations and clinical samples, or explore the influence of other demographic and psychological factors in other countries with different cultures.

Ethical Considerations

Compliance with ethical guidelines
This study was approved by the ethics committee of Ahvaz Jundishapur University of Medical Sciences (Code: IR.AJUMS.HGOLESTAN.REC.1400.060).

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for profit sectors.

Authors contributions
All authors contributed equally in preparing all parts of the research.

Conflicts of interest
The authors declare no conflict of interest.

Acknowledgments
The authors would like to thank all the students who participated in this research for their cooperation.

 

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