Cluster C personality disorders are a group of mental health conditions that cause intense fearfulness, insecurity, or perfectionism. The symptoms are long-term and impact many aspects of life.

Cluster C includes three specific conditions: avoidant personality disorder, dependent personality disorder, and obsessive-compulsive personality disorder. These conditions share some common traits, but each has distinct symptoms.

This article explores cluster C personality disorders, including what they are, the symptoms of each one, potential causes, and how they compare with the other clusters.

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Personality disorders are a group of mental health conditions that cause harmful patterns of behavior, distortions in thinking, and distressing emotions. These patterns are deeply ingrained and pervasive, affecting many areas of a person’s life.

Doctors use “clusters” to group personality disorders together based on the traits they share. “Cluster C” refers to a group of personality disorders that cause long-term feelings of anxiety and insecurity. They include:

People with AvPD have a deep-seated belief that they are unworthy or inferior and that others believe this too. This causes an overwhelming fear of being negatively evaluated by others, even though they might long for connection.

To cope with these feelings, a person with AvPD may avoid:

  • most or all social interactions
  • situations that might expose them to potential disapproval
  • trying new things or going to new places that might mean they have to talk to people

When they do interact with others, people with AvPD often suppress their true feelings, opinions, or beliefs. They will also be very sensitive to rejection or criticism.

AvPD has similarities with social anxiety disorder. Some experts feel that AvPD is a more severe form of the disorder rather than a distinct condition.

People with DPD feel helpless and have an excessive fear of separation or being left alone. This causes them to depend on other people to take care of them. The symptoms can include:

  • difficulty making everyday decisions without input from others
  • submissiveness, meaning a person allows others to take the lead
  • frequent need for reassurance, approval, or validation
  • seeking excessive emotional or practical support from others
  • difficulty expressing disagreement
  • feeling uncomfortable or anxious when alone
  • intense fear of abandonment

OCPD involves a preoccupation with control, orderliness, and perfection. People with OCPD believe that their way is the only “correct” way of doing things and set very high standards for themselves and others.

The symptoms of OCPD can include:

  • a strong desire for everything to be orderly and perfect
  • a rigid and inflexible approach to tasks, work, relationships, or morality
  • excessive use of rules, lists, and schedules, to the point that it detracts from the task at hand
  • delays in completing tasks due to repeated checking for mistakes and attention to detail
  • devotion to work at the expense of a person’s relationships or leisure time
  • reluctance to spend money
  • difficulty being adaptable, considering new ideas, or deviating from a plan
  • difficulty delegating tasks or working in a team
  • limited expression of emotions or affection, sometimes due to a focus on intellect over feelings

OCPD is not the same thing as obsessive-compulsive disorder (OCD). OCD is an anxiety disorder that causes distressing and intrusive thoughts, which a person then copes with by performing repetitive behaviors.

Sometimes, these compulsive behaviors can look similar to OCPD, as they can involve putting objects in a certain order or doing things until they feel “right.” However, the reasons for the rituals are very different. People with OCD perform compulsions to alleviate anxiety, and not to achieve perfection.

As with other personality disorders, the causes of cluster C personality disorders are complex. They likely occur due to a combination of factors, which may include:

  • Genetics: There could be a genetic predisposition toward developing certain personality disorders.
  • Childhood experiences: Adverse experiences during childhood, such as trauma or neglect, can teach a child not to trust others, that the world is dangerous, or that they are worthless. For example, parenting that dismisses a child’s feelings, provides little or no encouragement, or is abusive, has links to AvPD and may encourage people to fear negative judgment.
  • Temperament: All children have slight differences in how they perceive the world. Differences in development may influence how sensitive a person is to what they experience, their ability to regulate emotions, or how the brain responds to fear.
  • Culture: The rates of different personality disorders vary globally, which suggests that culture may play a role in the types of disorders that develop.

In total, doctors recognize 10 personality disorders that they divide into clusters A, B, and C. Cluster A includes conditions that cause unusual beliefs and behaviors, while cluster B includes conditions that cause dramatic or unpredictable behavior.

The cluster A personality disorders include:

The cluster B personality disorders include:

Each of these conditions causes different behaviors that people use to try and get what they think they need. For example, people with HPD engage in inappropriate behavior to gain attention, while someone with NPD might exaggerate their achievements to prove they are special or superior.

No, attention deficit hyperactivity disorder (ADHD) is not a personality disorder. It is a neurodevelopmental condition, which means it occurs due to differences in how the brain develops in childhood.

ADHD mainly affects a person’s ability to focus their attention. They may have difficulty focusing on some things, but then hyperfocus on others. They may also experience hyperactivity or difficulty controlling impulses.

Unlike personality disorders, ADHD does not cause distortions in a person’s beliefs, and if a person has the right support, it does not necessarily cause distress.

That said, people with ADHD can experience mental health difficulties, particularly if they often receive negative feedback from others about their symptoms. Some of the symptoms of ADHD can also look similar to those of a personality disorder.

For example, impulsivity and difficulty focusing may occur in both ADHD and BPD, and it is not uncommon for ADHD and BPD to occur together. Additionally, emotional dysregulation can be a feature of ADHD, as well as other cluster B personality disorders.

Cluster C personality disorders are a group of mental health conditions characterized by anxiety and fearfulness. They include AvPD, DPD, and OCPD.

These disorders cause persistent and harmful patterns of behavior and thinking, affecting how individuals perceive themselves and interact with others.