February 2012
Leroi I, Andrews M, McDonald K, Harbishettar V,
Elliott R, Byrne EJ, Burns A
Background: Apathy and impulse control disorders (ICDs) in
Parkinson’s disease (PD) are clinically important complications and may
exist on a common behavioral spectrum of disorders of reward and
motivation.
Objective: To directly compare PD participants with apathy those with ICDs on range of demographic, neurologic and psychiatric measures.
Methods: Ninety-nine non-demented PD participants (ICD, n = 35; apathy, n = 26; and controls, n = 38)
were assessed in the study. Univariate statistics were used to compare
the behavioral groups. A linear regression model was created with either
apathy or impulsivity as the dependent variable.
Results: The
two behavioral groups differed significantly from the PD control group
on similar factors but in opposite directions. The apathy group was older
at the time of both assessment and disease onset, had higher levels of
depression and lower dopamine agonist use, compared to the other two
groups. The ICD group was younger than the apathy group at disease onset
and had higher levels of anxiety, a higher overall dopamine load and
greater motor disease complexity. Overlap in behavioral pathology across
the two groups was also noted.
Conclusion: Apathy and ICDs
may be on a common behavioral spectrum in PD. Both are associated with
significant psychiatric morbidity supporting shared underlying
pathology.
