Dopamine ‘Overdose’ From Parkinson’s Meds Increases Risk for Sex Addiction
Certain treatments for Parkinson’s disease may increase risks for sex addiction-like behavior by altering the ways in which the brain responds to rewarding or pleasurable sensations, according to the results of a new study review from a group of Canadian researchers.
Doctors and researchers are well aware that people with Parkinson’s disease who receive a medication called levodopa or any one of a group of medications called dopamine agonists have increased chances of developing behaviors that mirror the behaviors associated with sex addiction. In a study review published in January 2015 in the journal Movement Disorders, researchers from three Canadian institutions explored the underlying reasons behind this phenomenon. These researchers concluded that use of the medications under consideration can alter the brain’s responses to pleasure-producing chemical signals.
People with Parkinson’s disease undergo a gradual, long-term loss of the ability to control their voluntary and involuntary muscle movements. Underlying this loss is damage and death in nerve cells in the brain responsible for producing a chemical called dopamine. In certain parts of the brain, the presence of this chemical facilitates proper control of the body’s fine and gross motor control systems. Conversely, when dopamine levels fall off, these motor control systems start to break down and lose their functionality. The symptoms of Parkinson’s—which include such things as abnormally stiff muscles, progressively worsening muscle tremors and an inability to blink or perform a range of other normally automatic movements—typically start to appear when damage in the brain’s dopamine-producing cells reaches or exceeds roughly 60 percent.
Levodopa and dopamine agonists are medications that address the loss of dopamine in different ways. When levodopa passes from the bloodstream to the brain, it gets chemically converted into dopamine and is subsequently stored for future use in the brain’s motor control networks. A second medication, called carbidopa, increases the effectiveness of levodopa. Dopamine agonists, on the other hand, don’t increase the brain’s dopamine supply. Instead, they act as dopamine substitutes and help restore functional muscle control.
Sex addiction is a non-substance-based condition that produces some of the same enduring changes in brain chemistry normally associated with an addiction to drugs or alcohol. However, instead of substance use, the underlying source of these changes is excessive and recurring involvement in sexual fantasy, sexual thought and/or or sexual behavior. As is true with substance addiction, the chemical alterations associated with sex addiction occur in a part of the brain called the pleasure center. Just like the brain’s muscle control network, the pleasure center relies heavily on dopamine. When dopamine levels increase, pleasurable sensations also typically increase in the individual.
Why Do Sex Addiction-Like Behaviors Arise?
In the study review published in Movement Disorders, researchers from Canada’s Toronto Western Hospital, University of Sherbrooke and Morton & Gloria Shulman Movement Disorders Centre explored the link between the consumption of levodopa and/or dopamine agonists and heightened chances of experiencing symptoms that mirror the effects of sex addiction (as well as the symptoms of other behavioral addictions such as gambling disorder and shopping disorder). Most of the available evidence supports a connection between the consumption of levodopa and the onset of addiction-like behavior. However, there is also evidence supporting a connection between such behavior and the consumption of dopamine agonist medications.
The researchers preliminarily concluded that roughly 3.5 percent of Parkinson’s disease patients develop behaviors normally associated with sex addiction (also known as compulsive sexual behavior or hypersexuality) after receiving levodopa or a dopamine agonist. They also preliminarily concluded that certain groups of Parkinson’s patients—including men, people affected by substance abuse and people affected by early-onset Parkinson’s symptoms—have increased chances of experiencing sex-related behavioral changes.
When the researchers looked at the reasons Parkinson’s medications can trigger symptoms of sex addiction or other types of behavioral addiction, they concluded that the same medication actions that beneficially increase dopamine levels in the brain’s muscle control networks can also trigger a dopamine “overdose” in the brain’s pleasure center. Essentially, this oversupply of dopamine in the pleasure center changes the way the brain processes pleasurable or rewarding sensations and makes addiction-like behavioral changes more likely. The researchers also concluded that some of the young people who eventually develop Parkinson’s may have pre-existing problems with dopamine processing in their pleasure centers. The presence of these problems may produce an increased susceptibility to behavioral addiction-related behaviors when Parkinson’s treatment later begins.