What Causes Paranoid Personality Disorder?

Written by:Ashley Ertel, LCSW, BCD

Published On: August 31, 2022

Medically reviewed by: Dr. Muhammad Munir, MD

Reviewed On: August 31, 2022

Updated On: July 14, 2023


People with paranoid personality disorder (PPD) are deeply suspicious and distrustful of those around them. They commonly view others as threats, which can cause them to exhibit hostile or even aggressive behavior. These paranoid thoughts and symptoms can be disabling and make it very difficult to engage in social interaction or form healthy relationships.

It’s believed that as many as 4.4% of the population might be living with this mental health condition of PPD. Yet, despite it being one of the more common types of personality disorders, research on the condition is limited. Due to the nature of PPD (relating to trust issues), it makes sense that people with this mental health condition may be hesitant to participate in clinical trials. Thus, experts are unsure of the exact cause of this personality disorder, although we have gained some insight into the condition over the years.

Keep reading to discover the research done on what causes paranoid personality disorder.

What Research Says About Causes of PPD

Not only is there very little research on PPD, but the existing studies that are out there generally look at all personality disorders rather than solely focusing on PPD. This makes it difficult to identify the causes of this specific disorder. That said, the research that has been done suggests that both genetic and environmental factors might play a role in the condition.

Primarily, researchers have found a correlation between childhood trauma and paranoid personality disorder diagnoses. One study found that approximately 78% of people diagnosed with PPD reported abuse and/or neglect during their childhood. This is significantly higher than the rate of early childhood trauma in the general population.

Studies also show that paranoid personality disorder is more common in families with a history of schizophrenia, affective disorder, or delusional disorder. Experts once believed that PPD was a precursor for schizophrenia, but that’s no longer the case. It is accepted, though, that there’s likely a genetic link between PPD and other mental health conditions.

“Paranoid personality disorder (PPD) is not typically seen in a clinical therapeutic setting as treatment is not often sought by those who might bear the significant mistrust of others, particularly those who might be in a position to provide care or solution. Historically, it had been thought to be a predictor of disabilities more often in men.”

Licensed Certified Social Worker-Clinical, (LCSW-C), LICSW, MSW Elizabeth Keohan

Potential Causes of Paranoid Personality Disorder

While the exact cause of PPD is still unknown, researchers have identified several potential risk factors of paranoia. It’s currently believed that both biological and environmental factors can impact whether a person develops this condition.

Biological factors

Our personality traits are highly complex, and studies show that our genes may influence certain parts of our personalities. For example, studies show that sensation-seeking behavior is a heritable trait. Research indicates that genetics probably play a role in the development of personality disorders like PPD as well.

As previously noted, PPD is more commonly seen in families with a history of psychotic conditions. While this suggests that PPD is at least partially heritable, it can be difficult to determine whether certain behaviors are passed down genetically.

Although it’s probable that some aspects of our personality are inherited, it’s also widely accepted that most people model the behaviors of the adults around them, which could explain why certain conditions are common in families.

Recent studies have also found that there may be a link between paranoid personality disorder and brain injuries. Some people have experienced a sudden increase in paranoid behaviors after a head injury, leading to a PPD diagnosis. Degenerative brain disorders, like Alzheimer’s disease, are also linked to paranoid behaviors, which suggests there could be a link between PPD and brain structure.

The mental health conditions that are linked with PPD impact dopaminergic function, which might help explain the genetic connections to PPD. Ultimately, more research is required to determine the role genes play in developing this personality disorder.

Environmental factors

It’s a given that genetics must play some role in our personality, but the environment we grow up in can also significantly impact how we see the world. For example, when people experience trauma at an early age, they may be at increased risk for developing a personality disorder.

People with paranoid personality disorder often mistake normal social behaviors for malicious acts. In some cases, it’s possible that this may be learned behavior caused by traumatic experiences. Due to their history, distrust in others might just be a rational (to them) way they try to protect themselves.

“Research lends itself to neglect and abuse being causal to paranoid personality disorder (PPD). It was once thought to be a precursor to schizophrenia, but findings have not been robust enough to make this genetic link decisive today.”

Licensed Certified Social Worker-Clinical, (LCSW-C), LICSW, MSW Elizabeth Keohan

Most studies that have examined the link between childhood trauma and PPD have focused on abuse and neglect from caregivers. However, research also suggests that other forms of trauma, such as severe pediatric burn injuries, also might increase the risk of developing PPD symptoms later in life. Finally, there may be a link between culture and increased risk for personality disorders as well, but studies show that paranoid personality disorder symptoms are similar across the world.

Risk Factors for Paranoid Personality Disorder

Even though experts don’t know exactly what causes paranoid personality disorder, they’ve identified several risk factors that can help predict the likelihood of PPD symptoms later in life.

Some risk factors might include:

  • Extreme stress, especially during childhood
  • Physical abuse
  • Emotional and physical neglect from caregivers
  • Chronic angry and aggressive behavior from caregivers
  • Suffering severe injuries in early childhood
  • Brain trauma
  • An unstable living environment
  • Never marrying
  • Being widowed, divorced, or separated

Having these factors in your life doesn’t mean you’re guaranteed to develop PPD, but they can increase your risk alongside other genetic and environmental factors. Research also indicates that people from disadvantaged backgrounds may be more likely to develop PPD. It’s been determined that PPD levels are higher for people who are part of a minority group and/or in lower income brackets, both of which can result in high-stress environments. Experiencing extreme stress levels on an ongoing basis can significantly predict PPD.

“A strong family history is certainly a risk factor for paranoid personality disorder (PPD), but it’s not often exclusive to chaos, emotional, and physical abuse or trauma, or prolonged and persistent exposure to a neglectful environment.”

Licensed Certified Social Worker-Clinical, (LCSW-C), LICSW, MSW Elizabeth Keohan

Understanding More About Paranoid Personality Disorder

The limited research we have on paranoid personality disorder means there aren’t many clinically-supported treatments for the condition. However, studies support that it’s very possible to manage symptoms of PPD through psychotherapy successfully. While therapy won’t cure PPD, it can make the condition much easier to live with.

People with PPD are suspicious of others, which can make it difficult for them to seek help or put their trust in mental health professionals. Over time, however, care providers can work to build trust and provide people with a system of support. In addition to therapy, medication can sometimes be beneficial in helping to ease the symptoms of PPD or comorbid conditions.

The lack of trust issues stemming from PPD might make people in early adulthood hesitant to seek psychiatric treatment, but accepting care can greatly enhance their quality of life. If you or a loved one has shown symptoms of PPD, a diagnosis and psychiatric treatment can give you the tools you need to manage this condition. The more we learn about what causes paranoid personality disorder, the better we can treat it. Paranoid personality disorder treatment can make it possible for someone to build relationships with others and lead satisfying lives.

If you’re ready to seek help, online therapy platforms like Talkspace, can make the process easy. Our experienced, trained therapists are ready to help you overcome PPD so you can live a healthy, rewarding life. Talkspace therapy is easy-to-access and affordable. Learn more about the causes of paranoid personality disorder, and how Talkspace can help you manage symptoms and paranoid thoughts today.

See References

Ashley Ertel, LCSW, BCD

Ashley Ertel, LCSW, is a Nationally Board Certified Licensed Clinical Social Worker. She has over a decade of experience specializing in trauma and depression, working primarily with first responders, military personnel, and veterans, and sexual assault survivors.

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