Paranoid personality disorder (PPD) is a mental illness characterized by paranoid delusions, and a pervasive, long-standing suspiciousness and generalized mistrust of others. People with this personality disorder may be hypersensitive, easily insulted, and habitually relate to the world by vigilant scanning of the environment for clues or suggestions that may validate their fears or biases. They are eager observers. They think they are in danger and look for signs and threats of that danger, potentially not appreciating other interpretations or evidence.They tend to be guarded and suspicious and have quite constricted emotional lives. Their reduced capacity for meaningful emotional involvement and the general pattern of isolated withdrawal often lend a quality of schizoid isolation to their life experience. People with PPD may have a tendency to bear grudges, suspiciousness, tendency to interpret others actions as hostile, persistent tendency to self-reference, or a tenacious sense of personal right. Patients with this disorder can also have significant comorbidity with other personality disorders, such as schizotypal, schizoid, narcissistic, avoidant and borderline. Causes
A genetic contribution to paranoid traits and a possible genetic link between this personality disorder and schizophrenia exist. A large long-term Norwegian twin study found paranoid personality disorder to be modestly heritable and to share a portion of its genetic and environmental risk factors with the other cluster A personality disorders, schizoid and schizotypal.Psychosocial theories implicate projection of negative internal feelings and parental modeling.
The full classification system based on this formula are displayed in the table below:

It is important to note that historically, there has been professional debate regarding the taurodont classification systems as to: 1) how much displacement and/or morphologic change constitutes taurodontism, 2) whether classification should be indexed stepwise or on a continuum, and 3) whether to include certain teeth in the occurrence of taurodontism. For example, as premolars are narrow mesio-distally, taurodontism is hard to identify radiographically on premolars. Therefore, some researchers exclude premolars from their classification systems. Additionally, there has been criticism over the use of landmarks that undergo changes. For example, due to trauma or wear, tertiary dentin can be deposited which can then alter some measurements; thus, caution should be employed when diagnosing taurodontism in this case. Finally, as these measurements are dimensionally quite small, they are also subject to large relative error. Clinical Considerations
The altered morphology of taurodont teeth can present challenges during dental treatment. Most notably, endodontists will have difficulty in not only removing the voluminous pulp, but also filling the large pulp chamber and complex root canal system. Prosthodontists and orthodontists should also exercise caution in using taurodont teeth as sites for dental anchorage. Due to the apical displacement of the furcation area, the taurodont tooth is not held as securely in the alveolar socket. Conversely, this may make taurodont teeth easier to extract. Finally, taurodont teeth may have favorable prognosis from a periodontal point of view, as the furcation area is apical and thus less susceptible to periodontal damage.