To the Editor: There are relatively few reports on the sexual behavior of patients with frontotemporal dementia (FTD), despite their disinhibited, impulsive, and compulsive behavior.^1–3 We report on a patient with FTD who manifested an intractable addiction to Internet pornography. We illustrates the potential appeal of this medium for sexual addiction in brain disease and suggest mechanisms for this behavior.

A 55-year-old, college-educated man had a 2-year history of a pronounced preoccupation with internet pornography. The patient needed to seek and view pornography throughout the day and even on a laptop while sitting in restaurants and other public places. In addition, he developed frequent masturbation. He had other personality changes. He had decreased goal-directed activities and verbal output. He had flatulence, eructation, and urination in public without excusing himself or showing embarrassment. He constantly ate sweets, gaining 100 lbs. In 1 year, and his self-care declined; he tended to wear the same clothes every day. The patient became emotionally disengaged; for instance, he failed to inquire about his father dying from cancer. When confronted with his behavior, he denied any changes in his personality. He had otherwise negative past medical and family histories except for late dementia in a grandmother. On examination, his Mini-Mental State Exam score was 27/30. His language was sparse but fluent. His 10-minute delayed recall was only 1/10 words; however, his memory for current events was intact even for details. The patient could do visuospatial constructions but failed Luria alternating programs and was concrete on proverb interpretations. The rest of his examination revealed intact cranial nerve, sensorimotor, and reflex testing. MRI was unremarkable, but positron emission tomography showed frontal and anterior temporal hypometabolism, right worse than left. This patient met criteria for FTD. He received escitalopram, a selective serotonin receptor inhibitor (SSRI), with a modest decrease in his viewing of pornography.

This patient had hypersexuality because of FTD. He had all the core features of that disorder, including abnormal interpersonal behavior, disinhibition, loss of empathy, decreased insight, dietary changes, and compulsive behaviors.^1,2 There are also alterations in sexual behavior in FTD, but a reduction in sexual drive and behavior is much more common than instances of hypersexuality.^2,3 Increased sexual behavior in FTD may result from compulsive disinhibition, rather than an increase in libido.⁴ Frontal lobe disorders can produce a generalized disinhibition, evident in this patient's other disinhibited acts, and compulsive tendencies can facilitate this disinhibition. In some FTD patients, hypersexual behavior can diminish with the treatment of compulsive behavior with SSRI medications.⁵ This patient's reward-seeking behavior further resembles an addiction in its continuation despite potentially adverse consequences. This sexual addiction may be particularly facilitated by the ready access and availability of Internet pornography. In sum, a new preoccupation for Internet pornography can be a symptom of a frontally predominant disorder such as FTD. The mechanism for this behavior likely involves disinhibited, impulsive behavior, facilitated by the compulsive tendencies and lack of concern for consequences that are part of FTD.