Comorbidity is when a person has more than one health condition at once. Researchers investigating the comorbidity of personality disorders have found people with certain disorders may have other conditions as well.

“Comorbidity” is the medical term for having more than one condition at the same time. Healthcare professionals may also use the terms “coexisting” or “co-occurring.”

Personality disorders are conditions that affect how a person thinks, feels, or relates to other people. Personality disorders can also affect behavior. There are several types of personality disorders with varying symptoms. People may have more than one at once.

Many researchers have investigated comorbidity in mental health generally. They have also investigated how people have multiple personality disorders together or with other health conditions.

This article discusses how common comorbidities are in mental health, including personality disorders with suicidal ideation and substance use. It also discusses co-occurring personality disorders.

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People with one mental health condition often develop others during their lifetime.

The prevalence of a condition is the number or percentage of people who have that condition in a specific time period. Comorbidities in mental health mean how many people in a certain group have one or more mental health conditions.

Several researchers have investigated how prevalent comorbidities are in mental health. However, there is not much recent scientific data on mental health comorbidities for large populations.

In 2018, researchers examined the prevalence of mental health comorbidities. They studied data from a survey of over 5,000 adults living in the United States. Researchers estimated roughly 1 in 3 U.S. adults who have had a mental health condition within the last year have more than one.

This study used data from surveys conducted by mental health professionals. However, these surveys dated from 2008–2012.

According to other research from 2015, the lifetime prevalence of having:

  • any psychological disorder is 46.4%
  • two disorders is 27.7%
  • three disorders is 17.3%

Lifetime prevalence is the proportion of people who will have these conditions at some point in their lives. The same 2015 research stated that over the last year, the prevalence of having:

  • any psychological disorder is 26.2%
  • two disorders is 5.8%
  • three disorders is 6%

However, this research used data from 2005.

One Danish study from 2019 investigated comorbidity within mental health disorders. Researchers studied data from health registers for nearly 6 million Danish people.

Researchers found that after a person has one mental health condition, they have an increased risk of developing all other mental disorders. People also have this increased risk for at least 15 years. The risk of mental health comorbidity is highest in the first year.

Having more than one mental health or personality disorder is common. According to the National Institute of Mental Health (NIMH), about 2 in 3 people with a personality disorder in the last year also had one or more other mental health conditions.

Learn more about personality disorders.

Suicidal ideation” is the term healthcare professionals use for a person thinking about attempting to end their own life.

Although there is no universally accepted definition, suicidal ideation describes a broad range of contemplations, wishes, and preoccupations with death and suicide.

People with a personality disorder have an increased risk of suicide.

Researchers in 2023 reviewed studies into suicide risk in people with personality disorders. They found people with personality disorders have an increased risk of suicide compared with people who have other mental health conditions or no mental health conditions.

Researchers also found that people with cluster B personality disorders are particularly at risk of suicidal ideation. Cluster B disorders affect a person’s emotions and behavior. They lead to actions that others may consider very emotional, erratic, or dramatic.

Cluster B personality disorders include borderline (BPD) and antisocial personality disorder. People with BPD often experience suicidal ideation.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

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It is common for a person to have a personality disorder and substance use disorder at the same time. Substance use disorder affects a person’s ability to control their use of drugs or alcohol.

BPD and antisocial personality disorder are some of the most common personality disorders that people may have with a substance use disorder.

According to the NIMH, nearly 22.6% of people with any personality disorder also have a substance use disorder, and 38.2% of people with BPD also have a substance use disorder.

A person may have more than one personality disorder. They may have signs or symptoms that meet the criteria for more than one diagnosis.

Since personality disorders are categorized into clusters based on how they affect an individual, it is likely that a person will experience more than one disorder from the same cluster.

However, healthcare professionals usually recognize that meeting more criteria for personality disorders typically means a more severe disorder.

The following are some questions people frequently ask about the comorbidity of personality disorders.

What are the comorbidities of multiple personality disorder?

Dissociative identity disorder (DID), formerly called multiple personality disorder, is the presence of at least two varied personalities in one person.

People with DID may also have post-traumatic stress disorder (PTSD), a substance use disorder, or BPD. They may also experience anxiety or depression and be at risk of self-harm.

What are the 3 overlooked signs of a personality disorder?

People with a personality disorder may not seek medical attention for their condition. They may overlook several personality disorder signs, which can vary from person to person.

Mental health resources

Visit our dedicated hub for more research-backed information and resources on mental health and well-being.

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People may have more than one mental health condition at once. This is called comorbidity. People with a mental health condition may be more at risk of other mental health conditions over time.

Personality disorders affect a person’s behavior and how they think, feel, or relate to other people. People with a personality disorder may have several mental health comorbidities.

Some types of personality disorders may make a person more at risk of suicidal ideation or substance use disorder. People may also have more than one personality disorder at once.