1. Impulse Control Disorders (ICD) and Parkinson Disease (PD)
Sotirios A. Parashos, MD, PhD
Minneapolis Clinic of Neurology
and
Struthers Parkinson’s Center

2. Disclaimer
This presentation contains discussion of use of medications for indications not approved by the FDA

3. What are ICDs? Disorders characterized by impulsivity
Impulsivity is a tendency to engage in behaviors that offer a small temporary gain despite the fact that they lead to a much greater long term loss
People with ICD are repeatedly unable to resist these behaviors
In Psychiatry ICDs are classified with Obsessive Compulsive Disorders
They are often associated with substance use disorders

4. What are the symptoms? Pathological gambling Hypersexuality Hoarding
Compulsive or binge eating
Compulsive shopping
Punding
Dopamine dysregulation syndrome (DDS)
Excessive hobbying
Drug addiction

5. What are ICBs and how are they different from ICDs?
Impulsive behaviors may not necessarily be classified as a “disorder”
Psychiatrists consider certain behaviors as a disorder, only if the behavior impairs the person’s normal functioning
The term “impulse control and compulsive behaviors” has also been used in the PD literature, as some of these behaviors may be relatively “benign”

6. Why in PD?
Dopamine is the “feel good” chemical in our brain (a function of the D-3 type dopamine receptors in the limbic system – the “emotional brain”)
PD affects a person’s “executive functions”, one of which is inhibition control; the subthalamic nucleus, a cluster of cells in the brain inactivated by DBS plays a role in inhibition control.
Depressive traits, common in PD, are a well known risk factor for ICDs
The combination of decreased inhibition control, a “negative” affect, and a “feel good about it” effect from dopamine-like drugs used to treat PD can result in impulse control disorders
Similar behaviors are often seen in cocaine addiction – cocaine exerts some of its actions through dopamine in the brain

7. What brings on ICDs in people with PD?
Drugs:
Dopamine agonists (pramipexole, ropinirole, rotigotine, piribedil, cabergoline): ICDs have been reported with these medications in people without PD who take them for RLS, or pituitary hormonal disorders
L-dopa
Selegiline
Amantadine
Deep Brain Stimulation Surgery (DBS)

8. How often do they happen? Part 1
Multiple studies in PD have reported a frequency of ICDs and ICBs of up to 14%
In one series of 159 persons with PD undergoing DBS:
28 qualified for a diagnosis of ICD or DDS
17 developed the problem after the surgery (Moum et al. PLoS One. 2012;7(1))
In a study of 140 people with restless legs syndrome (RLS) 10 had ICDs – suggesting that drug treatment is an important, independent factor
8/10 were taking a dopamine agonist
2/10 were taking l-dopa (Voon et al. BMC Neurol Sep 28;11:117 )

9. How often do they happen? Part 2
In PD the following frequencies have been reported:
Pathological gambling: 3.4 – 8 %
Hypersexuality: 2 – 3.5 %
Punding: 1.4 – 4.2 %
DDS: 3.4 – 4.1 %
Compulsive shopping: 3.4 – 5.7 %
Binge eating: 4.3 %

10. What can be done about ICDs? Step 1
Prevention first!
An informed patient/care-partner
Assessment of risk factors (personality traits, depression, support system) before prescribing dopamine agonists
If ICB is not problematic, a frank discussion with carepartner and doctor may be all that’s needed

11. What can be done about ICDs? Step 2a
Reduce the dose of the suspected drug
Sometimes that is sufficient – if not, then
Discontinue the suspected drug
Switch to a different drug
If the drug is absolutely necessary, then add a medication to help control the ICD
SSRI and SNRI antidepressants
Atypical antipsychotics (like quetiapine)
Anticonvulsants (like carbamazepine)
Opioid antagonists (like naloxone)
Amantadine (?!)

12. What can be done about ICDs? Step 2b
Assess the psychological factors that may be contributing and consider counseling
Cognitive behavioral therapy
Family/carepartner/provider interventions
Limit access to credit cards, bank accounts etc. for pathological gambling and shopping
Minimize junk food, snacks etc. in the home and work environment for overeating
Special medications affecting sexual function may work for hypersexuality
Strict control of prescriptions, alerting the pharmacist and allowing only one doctor to prescribe l-dopa for DDS