April 14, 2021

Parkinson’s Disease Symptoms – Neuropsychiatric Dysfunction


As we learnt in Parkinson’s disease early symptoms, Parkinson’s symptoms can be categorized into the 4 Cardinal Signs, Associated Symptoms and  Neuropsychiatric Dysfunction.

Neuropsychiatric Dysfunction associated with Parkinson’s can be viewed in terms of a patient’s state of mental well-being, and possible issues related to Dementia.

Mental Well-Being

A Parkinson’s patients mental well-being can be affected by a reaction to the disease, chemical changes in the brain e.g. research indicates acetylcholine is linked to a person’s mental state and serotonin to one’s mood, or the side effects of medications used to manage the disease (therefore may not be due to dementia noted later). This can affect the patients daily life, relationships and ability to socialize significantly. Aspects of mental well-being include:

  • Behavior, personality and mood alterations:
    • Antisocial or becoming withdrawn.
    • Apathy.
    • Anxiety.
    • Depression.
    • Hallucinations and delusions occur in approximately 5% of patients.
    • Impulse control issues e.g. cravings.


  • Cognitive disturbances :
    • Decreased attention span.
    • Executive dysfunction (executive function deficit (EFD): Ability to plan and execute appropriate actions.
    • Impaired memory and recall
    • Reduced mental:
      • Agility.
      • Clarity. Often described as a ‘dullness/dull thinking’
      • Flexibility.
      • Slowness (Bradyphrenia) including slow response to questions.
    • Visuospatial difficulties including facial recognition.




  • Depending on the source of data:
    • Between 30-40% of patients will experience some degree of cognitive impairment and memory problems. Some research suggests this rises to 80% after 8-10 years of the disease.
    • Between 1/5 and 1/3 of Parkinson’s patients develop some form of Parkinson’s Disease Dementia (PDD). The figure commonly quoted is around 20%.
  • The rate of progression and severity of dementia varies considerably between individuals.
  • Parkinson’s Disease Dementia typically takes 10-15 years to develop from initial Parkinson’s diagnosis. It is therefore considered to occur towards the later stages of the disease.
  • Parkinson’s disease patients have a  4- 6X greater risk of developing cognitive impairment or dementia than the general population.
  • Various issues arise regarding Parkinson’s Disease Dementia including:
    • Significant symptoms noted above in Mental Well-Being.
    • Increased mortality rate.
    • Reduced quality of life for patient and increased burden for family and carers/caregivers.
    • Nursing home care more likely.
  • It must be remembered that dementia symptoms can be caused by a variety of unrelated conditions and medications e.g. Vit B12 deficiency, underactive thyroid gland, depression, Alzheimer’s disease.

GENERAL OVERVIEW OF DEMENTIA : Description-Assessment-Types


The next article will consider the fundamental question of What is Parkinson’s Disease ?