Distinguishing PD from mental illness and learning disability

Mental illness

The distinction between mental illness and personality disorder does not always stand up to close scrutiny, they were considered to be separate categories of mental disorder. That said mis-diagnosis is a common problem.

  • Mental illnesses are thought to have an identifiable onset, in which a period of illness interferes with the sufferer’s baseline level of functioning.
  • Furthermore, severe mental illnesses are traditionally treated with medication and when treated effectively, the sufferer may return to a state of wellness. However relapses can occur.
  • In contrast however, the symptoms associated with personality disorder form part of the personality system, are therefore chronic and enduring and are generally less likely to be responsive to medication.
  • Despite this distinction, many people diagnosed with personality disorders also meet the criteria for mental illnesses such as depression or schizophrenia. It is also suggested that having a personality disorder may increase one’s risk for developing mental illness.

Learning disability

The distinction between learning disability and PD is controversial and distinguishing the two is complex. The reasons for this include the following:

  • The behavioural and emotional presentations found in learning disabled groups may mimic the symptoms of personality disorder. For example, some personality disordered individuals may achieve very little academically at school, but it is their emotional state (and life experiences) rather than their inherent cognitive ability which has interfered with a capacity to learn new information.
  • The assessment of PD is made more difficult in individuals with learning disability as the individual concerned may not possess sufficient reflective capacity to provide meaningful insight into their thoughts and feelings. For example, poor victim empathy may in fact be related to cognitive difficulties in verbal expression and perspective taking.

However, personality disorder may be identified in individuals with learning disabilities, particularly where the level of impairment is less severe. The greater the level of intellectual impairment, the less likely that personality disorder is an appropriate diagnosis.