Dopamine Dysregulation Syndrome

Dopamine dysregulation syndrome is a rare complication of Parkinson's disease treatment. It triggers serious behavioral disturbances.

Written and verified by the psychologist María Alejandra Castro Arbeláez.

Last update: 21 December, 2022

Various neurotransmitters circulate through our nervous system. These are chemicals that promote or inhibit certain functions of our body. However, there can be a series of problems linked to neurotransmitters, such as dopaminergic dysregulation syndrome (DDS).

Dopamine is a neurotransmitter that’s caused controversy in neuroscience for years. In fact, there are more than 110,000 scientific articles in which it’s referenced. In addition, it’s become well known in popular culture. But what’s its relationship with Parkinson’s disease?

Dopaminergic dysregulation syndrome (DDS)

Let’s start by exploring what dopamine is. It’s a chemical that transmits signals between nerve cells in the brain. One of the areas where it’s most commonly located is in the substantia nigra, but it can also be found in the ventral tegmental area.

Dopamine dysregulation syndrome is a complication that can occur in the treatment of Parkinson’s disease. It’s not usually that frequent and is associated with the excessive use of dopaminergic drugs.

This syndrome is related to Parkinson’s disease, a common degenerative disorder characterized by manifestations in the motor area. It usually affects people over 60 years of age, although it can occur in young people. Here are some of its clinical features:

• Tremor at rest.
• Rigidity.
• Slowness in initiating voluntary movement.
• Progressive reduction in the amplitude, speed, and repetitive action of the movement.
• Postural instability.
• Sleep disorders.

In addition, autonomic dysfunction may occur. For example, airway blockage, dizziness, temperature intolerance, sexual dysfunction, abnormal sweating, etc. Also neuropsychiatric and behavioral disorders, such as depression and anxiety, dementia, psychosis and hallucinations, impulse control disorders, and dopaminergic dysregulation syndrome.

Dopamine and Parkinson’s disease

To understand dopamine dysregulation syndrome, we need to understand more about the relationship between dopamine and Parkinson’s disease. As we mentioned earlier, this neurotransmitter is found in an area of the brain called the substantia nigra, which is part of the basal ganglia, located above the striatum.

Its relationship with Parkinson’s disease is linked to the fact that dopamine is responsible for helping to control movement. Without it, the messages sent to the muscles responsible for movement would be much less effective. That’s why we see motor-related difficulties in Parkinson’s disease.

The substantia nigra area is consequently affected by Parkinson’s disease. In fact, the neurons responsible for the production of dopamine slowly die, which causes difficulty in movement. It’s a problem that tends to worsen over time.

Causes and symptoms of dopamine dysregulation syndrome

Dopamine dysregulation syndrome is often misdiagnosed and even unrecognized. In addition, it also frequently occurs alongside other conditions. Early identification is essential because the syndrome causes significant functional, emotional, physical, social, and behavioral deterioration.

For the relief of the motor manifestations typical of Parkinson’s disease, dopaminergic replacement therapy is used. It aims to control symptoms associated with movement caused by dopamine deficiency in the nigrostriatal region.

This therapy activates the neurons of the mesocorticolimbic region associated with the reward system. The activation can cause behavioral alterations. Furthermore, it can produce, among other symptoms, addiction, and withdrawal.

Therefore, although this therapy is essential for the treatment of the motor symptoms of Parkinson’s disease, it can also trigger some alterations such as:

• Hypersexuality.
• Compulsive buying.
• Compulsive eating.
• Mood changes.
• Psychosis.
• Insomnia.

In addition, dopaminergic dysregulation syndrome, which is also called homeostatic hedonistic dysregulation, is associated with high doses of levodopa or short-acting dopamine agonists. It usually occurs in patients in whom the evolution of the disease is greater.

This syndrome is a neuropsychological behavioral disorder. According to research conducted by Suárez, Arcila, and Cruz, it’s associated with the development of addiction.

One of the alarming signs of the syndrome is that the patient begins to take more of the dopaminergic drug, even though there’s a worsening of the involuntary movement disorder, induced by the same drug.

In addition, patients come to show changes in mood in a cyclical way, especially hypomania or psychotic mania. These symptoms make the diagnosis of dopaminergic dysregulation syndrome difficult since they’re usually attributed to a primary psychiatric disorder.

Punding and impulse control disorder

The performance of repetitive behaviors without purpose, also called punding, is included by some authors as one of the symptoms of this syndrome. Others consider it as a differentiated symptom. Certainly, it overlaps in some patients, as do impulse control disorders. That’s why diagnosis is often difficult.

In impulse control disorders, there’s evidence of an impulse to perform acts for immediate gratification or pleasure. This harms the individual psychologically, socially, legally, physically, and financially. These disorders are also associated with dopaminergic treatments, especially with the overuse of agonists. In fact, in scientific research, there’s a debate about whether these conditions and dopamine dysregulation syndrome should be considered addictive behaviors.

In short, dopaminergic dysregulation syndrome can occur during the course of Parkinson’s disease, when it’s being treated. It’s rare and is characterized by addictive behavior, accompanied by the excessive use of dopaminergic drugs. However, it’s difficult to diagnose due to its possible comorbidity with mood disorders, purposeless repetitive behavior, and impulse control disorders.