Dopamine dysregulation syndrome

Dopamine dysregulation syndrome (DDS) is a dysfunction of the reward system observed in some individuals taking dopaminergic medications for an extended length of time. It typically occurs in people with Parkinson's disease (PD) who have taken dopamine agonist medications for an extended period of time. It is characterized by problems such as addiction to medication, gambling, or sexual behavior. The most common symptom is craving for dopaminergic medication. However other behavioral symptoms can appear independently of craving or co-occur with it. Craving is an intense impulse of the subject to obtain medication even in the absence of symptoms that indicate its intake. To fulfill this need the person will self-administer extra doses. When self-administration is not possible, aggressive outbursts or the use of strategies such as symptom simulation or bribery to access additional medication can also appear. Hypomania, manifesting with feelings of euphoria, omnipotence, or grandiosity, are prone to appear in those moments when medication effects are maximum; dysphoria, characterized by sadness, psychomotor slowing, fatigue or apathy are typical with dopamine replacement therapy (DRT) withdrawal. Different impulse control disorders have been described including gambling, compulsive shopping, eating disorders and hypersexuality. Behavioral disturbances, most commonly aggressive tendencies, are the norm. Psychosis is also common. Parkinson's disease is a common neurological disorder characterized by a degeneration of dopamine neurons in the substantia nigra and a loss of dopamine in the putamen. It is described as a motor disease, but it also produces cognitive and behavioral symptoms. The most common treatment is dopamine replacement therapy, which consists in the administration of levodopa (L-Dopa) or dopamine agonists (such as pramipexole or ropinirole) to patients. Dopamine replacement therapy is well known to improve motor symptoms but its effects in cognitive and behavioral symptoms are more complex.