Parkinson’s disease is the second most common neurodegenerative disorder behind Alzheimer’s disease. It is also the fastest growing neurological disorder in the world. It has been known for some time that Parkinson’s disease is associated somehow with an increased occurrence of distressing dreams and nightmares. What is not known is whether these types of dreams precede the development of Parkinson’s disease.
Nightmares
Various studies show that alterations in dreams are associated with Parkinson’s disease. Content of dreams may be changed including negative emotions and increased physical aggression. Rapid eye movement disorder may also occur leading to dream enactment behaviors which involve physically acting out distressing dreams or nightmares. Enactment may include making loud verbal noises or violently swinging arms and legs.
Research Findings
Individuals with Parkinson’s disease are four times more likely than the general population to have nightmares that are considered clinically significant. Around 25% of people start to experience bad dreams at the time of diagnosis and they may be more likely to develop early movement and cognitive problems.
Up to 78% of people with Parkinson’s-related dementia report weekly nightmares, whereas only 17% of those with Parkinson’s but not the related dementia, report such dreams. In the general population, by contrast, only 2% to 5% report weekly nightmares.
One early study found that 81% of people with Parkinson’s disease said they had frequent, intense, vivid and very frightening dreams shortly after they were diagnosed. They also believed that changes in their dreams were related to the onset of their movement problems by years.
Age and Gender
Many studies show that the onset of nightmares in the general population begin around the age of 70, which is right around when symptoms of Parkinson’s first develop. Women are more likely to have bad dreams and nightmares weekly between adolescence and middle adulthood, but from age 65 onward, there is no gender difference. Therefore, the age-related increase in bad dreams is most evident in men.
Parkinson’s Disease, Nightmares and the Brain
What is happening in the brain that links Parkinson’s disease to nightmares? Evidence shows that during rapid eye movement (REM) sleep, which is the stage of sleep where nightmares generally occur, there is increased activity and blood flow in limbic and paralimbic areas. These systems regulate emotions while awake as well as during the dreaming phases. This may explain why some dreams can be hyper-emotional.
Some studies show that structural changes in the right frontal lobe are associated with increased frequency of distressful dreams and nightmares. In one study, individuals with left-onset Parkinson’s, which is related to right hemisphere pathology) were more likely to report frequent distressing dreams than those with right-onset Parkinson’s disease.
It has also been found that nightmares may be associated with cognitive decline due to Parkinson’s disease as well as severity of depression and anxiety. Since bad dreams and mood changes are commonly seen in those with the disorder, it is thought that they are caused by the neurodegeneration of the right frontal regions of the brain, which could be thought of as a “neurocognitive model of nightmares”.
Final Thoughts on Parkinson’s Disease and Nightmares
There has been a dramatic increase in the number of people diagnosed with the chronic, debilitating and irreversible neurodegenerative condition called Parkinson’s disease. Among its many symptoms, people will most likely experience motor disturbances and movement problems and fluctuations in mood, including depression, apathy and anxiety. It has also become clear in science, that stressful dreams and nightmares may also be part of the clinical picture as well as a forerunner to the diagnosis itself.