Given the innate sensitivity of the topic, it is very likely that hypersexual behavior is under-reported. Despite the limitations (and probable underestimation) of a mail-in survey, the prevalence of hypersexuality in our PD cohort (4.3%) was slightly higher than the 2.4% reported by Voon and colleagues.1
Patients with a younger age of PD onset were more likely to exhibit hypersexual behavior.
Previously, hypersexuality was associated with males but not females.1
Our current study failed to substantiate this finding. This highlights the possibility of hypersexual behavior in female patients that may be missed due to the inherently small sample size of hypersexual patients.
Although the association between younger age of onset and hypersexual behavior might be thought to be due to a greater use of dopamine agonist therapy in these patients, no significant relationship was found between dopamine agonist therapy and hypersexual behavior in this sample. Klos and colleagues found that hypersexual behavior typically began after eight months of dopamine therapy and then resolved after discontinuing dopamine agonist therapy.5
It should be noted that a few patients in our study did mention a similar experience. Shaw and colleagues proposed dopamine therapy in general may cause hypersexuality both directly, by increasing libido and arousal, and indirectly by interacting with reward-center neural substrates.2
This is in line with the Voon and colleagues finding that a higher total levodopa dose equivalent, but not dopamine agonist dose, was associated with hypersexuality.1
Intuitively, it seems very likely that manipulation of the dopamine system would result in changes in reward-seeking behavior. Additional compulsive behaviors coincide with hypersexuality in up to 60% of hypersexual PD patients.5
Given that only a relatively small percentage of PD patients exhibit hypersexuality or any type of impulse control disorder, it seems likely that susceptibility may be due to underlying heritable temperamental traits such as novelty-seeking.6
Moreover, Pontone and colleagues found an association between impulse control disorders and depressed mood, disinhibition, irritability, and appetite disturbance.7
shows demographic data from our current hypersexual population. While not statistically significant, five out of six patients had either a personal or family history of previous psychiatric disorders. Notably, none of the patients had a history of hypersexual behavior prior to PD onset. Also, there appears to be a trend of elevated depression scores, as measured by the BDI, in a majority of these patients.
Demographic data of hypersexual behavior patient sample
It should be noted that this study relied on a population of patients all from a single Movement Disorders Center. Therefore it is possible that it does not represent the general PD population. Similar studies in subsequent populations would help to eliminate the possibility of a population bias.
Also, due to survey limitations, as well as possible patient cognitive decline, it is possible that not all patients understood the survey questions as intended. Since we relied on initial self-identification of hypersexual behavior before interviewing, it is quite possible that not all patients were able or willing to make this identification. In the future, studies with a larger hypersexual sample size might serve to verify significant demographic variables.
Our study suggests that hypersexuality may be more prevalent than currently realized. It confirms previous reports that it occurs more commonly in the younger PD age group. Clinicians should be aware of possible hypersexual behavior in both sexes, regardless of dopamine agonist therapy, and be prepared to provide information and support to their patients and their patients’ caregivers.