An obsessed, frazzled man at his computer.

If preoccupation with the Internet is a new behavior, consider the possibility that there might be an underlying medical cause. 

Dopamine-Agonist Medications in Patients with Parkinson’s Disease

The first report of Internet gambling addiction in a patient on dopamine-agonist medications for Parkinson’s disease was in 2005.

The patient was a 41 year-old computer programmer with Parkinson’s disease. Soon after reaching a therapeutic dose of the dopamine-agonist medication he became “consumed” with Internet gambling. He lost $5000 in just a few months. This behavior was entirely new and out of character for the patient. Once the medication was discontinued, the patient’s gambling obsession ceased--just as suddenly as it had begun. 

In 2006, Dr. Andrew Larner published another case report entitled, “Medical Hazards of the Internet: Gambling in Parkinson’s Disease.” This patient was a man in his mid-40’s with Parkinson’s disease. After Dr. Larner increased the patient’s dopamine-agonist medication dosage, a behavioral change occurred. The patient became obsessed with gambling on the Internet. He also subscribed to several Internet services, including a pornography site. Again, this behavior was entirely uncharacteristic for the patient. Because the medication change had improved the patient’s mobility, it was only after the patient had accrued considerable debt that was he willing to stop taking it.

Individuals with Parkinson’s disease who are taking dopamine-agonist medications have an increased risk of developing an impulse control disorder, most commonly: gambling, compulsive sexual behavior, and/or compulsive spending. In today’s world, the Internet may be utilized to give expression to these impulses.

Fronto-Temporal Dementia

In 2011, Mario Mendez and Jill Shapira published a letter in which they reported the case of a 55 year-old man who was compulsively addicted to Internet pornography. 

The situation was extreme. This college-educated man had become obsessed with Internet pornography to the point of actually viewing pornography sites on his laptop in public places such as restaurants. This behavior was associated with other personality changes and had been going on for 2 years before he came to medical attention. This man had fronto-temporal dementia (FTD). 

Individuals with FTD start to behave in ways that they never would have allowed of themselves before their brain disease began to manifest itself. The individual in this report had started to urinate in public places and also to masturbate excessively. He compulsively ate sweets and gained a striking 100 lbs. He began to wear the same clothes day after day. He failed to inquire about his dying father.

What is remarkable and crucial for readers to note is that this man’s memory for recent events was excellent. Also, when he was initially medically evaluated, his brain MRI (magnetic resonance imaging) was unremarkable. Evidence of brain disease was revealed only with a thorough neurological examination and PET (positron emission tomography) imaging. 

Most people picture dementia as memory loss in an elderly individual; that is the usual course of Alzheimer’s disease. But fronto-temporal dementia (FTD) is different. Most often FTD begins in mid-life, although people may be affected in their 30’s or as late as in their 90’s. The personality changes come on gradually, and this leads people around the patient to interpret the new behavior as having psychological roots. Early symptoms are usually apathy and lack of initiative; this can look like depression. Other early manifestations are impulsivity and decreased inhibition. Additional symptoms include: diminished concern about the consequences of actions, lack of empathy, lack of flexibility, and a dramatic absence of insight. 

FTD is not a rare disease. It accounts for up to half of all the dementias in people who are under 65 years of age. Many components of FTD can contribute to Internet addiction: impulsivity, diminished inhibition, lack of regard for moral and social norms, a tendency toward compulsive behavior, and excessive self-involvement.


There are some needles in the haystack of Internet addiction. 

Researchers have found a significant association between Internet addiction and a variety of psychiatric conditions: alcohol abuse, attention deficit hyperactivity disorder, depression, and anxiety. In addition, there are a small percent of people with Internet addiction who have medical conditions that are driving their behavior. As with any covert medical condition, an accurate diagnosis can be game changing.  

Barbara Schildkrout, MD is the author of:

  • Masquerading Symptoms: Uncovering Physical Illnesses That Present as Psychological Problems
  • Unmasking Psychological Symptoms: How Therapists Can Learn to Recognize the Psychological Presentation of Medical Disorders.


Dodd, M. L., Klos, K. J., Bower, J. H., Geda, Y. E., Josephs, K. A., & Ahlskog, J. E. (2005). Pathological gambling caused by drugs used to treat Parkinson disease. Archives of Neurology62(9), 1377-1381.

Ho, R. C., Zhang, M. W., Tsang, T. Y., Toh, A. H., Pan, F., Lu, Y., ... & Mak, K. K. (2014). The association between internet addiction and psychiatric co-morbidity: a meta-analysis. BMC psychiatry14(1), 183.

Larner, A. J. (2006). Medical hazards of the internet: Gambling in Parkinson's disease. Movement disorders21(10), 1789-1789. 

Mendez, M., Lauterbach, E., & Sampson, S. (2008). An evidence-based review of the psychopathology of frontotemporal dementia: a report of the ANPA Committee on Research. The Journal of neuropsychiatry and clinical neurosciences20(2), 130-149. 

Mendez, M. F., & Shapira, J. S. (2011). Internet pornography and frontotemporal dementia. Journal of Neuropsychiatry and Clinical Neurosciences23(2), E3. 

Weintraub, D., Koester, J., Potenza, M. N., Siderowf, A. D., Stacy, M., Voon, V., ... & Lang, A. E. (2010). Impulse control disorders in Parkinson disease: a cross-sectional study of 3090 patients. Archives of neurology67(5), 589-595.

About the Author

Barbara Schildkrout

Barbara Schildkrout, M.D., an Assistant Clinical Professor of Psychiatry at Harvard Medical School, is the author of Masquerading Symptoms.

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