A 70-year-old male patient reported to the Department of Neurology, Dr. Ram Manohar Lohia Hospital in New Delhi for the chief complaint of forgetfulness for the last 8 years with agitated behavior and disinhibited sexuality. For the last five years, the patient started using sexually explicit language, which was out of keeping with his premorbid history. He then started touching and grabbing his wife's genitals in front of family members.

Upon further probing, it was found that he forced his wife to have sexual intercourse with him 3–4 times during the night and when he gets the opportunity during the daytime. If she refused, he would become aggressive and violent and beat her severely. He also made sexual advances towards other females around him and passes indecent remarks. He has been observed masturbating by caregivers.

A mental status examination revealed that the patient was poorly groomed and unkempt. He had delusions of persecution, reference, and infidelity. Auditory hallucinations were present. His Mini Mental Status Examination score was 16/30, indicating severe cognitive impairment. His routine general physical systemic examination and laboratory investigations were within normal limits. His liver and kidney function tests reveled no abnormality and he tested negative for HIV, Venereal Disease Research Laboratory Slide Test, and Fluorescent Treponemal Antibody Absorption Test. His serum B12 levels were within normal limits. An MRI of the brain revealed atrophy of the temporal sulci, temporal horns, and dilated third ventricle. A clinical diagnosis of dementia of Alzheimer's type (AD) was made and we put the patient on Olanzapine 5 mg per day, following which his sexual disinhibitions were reduced.

Sexual disinhibition is a type of “acting out” behavior. There is some evidence linking hypersexuality to frontal and temporal lobe pathology (Pilleri, 1966). It is believed to occur due to loss of cerebro-cortical inhibitor mechanisms. Several drugs, such as antidepressants, anxiolytics, hormones (e.g., estrogen, progesterone, medroxyprogesterone acetate, androgen blockers (cyproterone acetate), and lithium have been used to treat hypersexuality (Hashmi, Krady, Oayum, & Grossberg, 2000). Although a rare manifestation of AD, hypersexuality is one of the most embarrassing behaviors for caregivers (Robinson, 2003).

Hypersexuality has also been reported in other types of dementias. A nursing home study of demented patients noted behaviors such as inappropriate cuddling, touching of the genitals, sexual propositions, grabbing and groping, use of obscene language, and masturbating without shame (Nagaratnam & Gayagay, 2002). A case report of urethral masturbation and sexual disinhibition as manifestations of behavioral and psychological symptoms of dementia have been described in a 90-year-old patient who repeatedly self-inserted foreign bodies into his urethra (Rosenthal, Berkman, Shapira, Gil, & Abramovitz, 2003). Significant reduction of his sexual behavior was achieved with low doses of Haloperidol. Similar symptoms are noted in Pick's disease, other fronto-temporal lesions, mania, and following a seizure or treatment of Parkinson's disease, and have been described as Kluver-Bucy type.

Our case had probable dementia of AD type with grossly disinhibited sexual behavior and engaged in penetrative vaginal intercourse along with several other behavioral symptoms suggestive of sexual voracity. He responded to Olanzapine. Though sexual disinhibition is a very rare manifestation of AD, to our knowledge, this is the first case of AD who engaged in invasive and unwanted sexual intercourse with his wife.