A Case of Late-Onset Obsessive Compulsive Disorder Developing Frontotemporal Lobar Degeneration

A 56-year-old married man first presented with symptoms of OCD at the age of 40 years. He repeatedly checked door locks and turned off water supplies and electric outlets before he left home. Five years later, he developed another OCD symptom, namely, obsession with contamination, leading him to wash his hands frequently and waste a lot of soap each day. At the age of 45 years, he visited a psychiatric clinic with his family to seek treatment, as he was distressed with these obsessions, including compulsive hand washing, and had no control over the symptoms. With medications (SSRIs, SRIs), although his obsession with contamination and compulsive washing improved, his checking rituals only worsened. Around this time, his Yale Brown Obsessive-Compulsive Scale (Y-BOCS) score was estimated to be 32. After the age of 53, he gradually became more and more apathetic, with severe OCD symptoms. At the age of 56, he was referred to our hospital as an outpatient for behavioral therapy to deal with his OCD symptoms. However, by this time, he had lost insight into his OCD symptoms. He was no longer distressed by his repeated checking rituals. During the following year, his behavioral patterns gradually changed. He began to exhibit stereotypic behaviors, such as buying the same kind of food at the same superstore every day, and walking from the back to the front of the train at a certain time. While the symptom of checking rituals decreased in severity, these stereotypic and ritualistic behaviors became more and more marked. Nonetheless, he did not express any anxiety about these behavioral changes; on the contrary, he began to exhibit euphoric symptoms, such as joking and laughing and singing in inappropriate situations. Both at the time of the first visit to our clinic and at the age of 57 years, MRI showed mild bilateral frontal lobe atrophy. No other abnormal findings could be detected on the MRI. Brain ECD-SPECT showed hypoperfusion in the frontal lobes. With regard to neuropsychological examination, his memory, language, and visuospatial functions were well preserved. However, he demonstrated deficits of executive function. In the Neuropsychiatric Inventory 3 (NPI), he had high scores for euphoria, apathy, disinhibition, and aberrant motor behavior.

The present case had a long history of OCD symptoms appearing after the age of 40 years. During the first 10 years after the onset at the age of 40 years, he recognized both the obsessions and the compulsions as unreasonable, and these symptoms caused distress. Therefore, he fulfilled the DSM-IV criteria for the diagnosis of OCD. However, around 57 years of age, he began to exhibit behavioral and personality changes, including stereotypic behaviors, euphoria, and disinhibition, which together with the loss of insight into the symptoms, were consistent with the clinical features of FTLD as defined by Neary et al. 4 Both the neuropsychological and brain imaging findings also supported the diagnosis of FTLD.

Compulsive behaviors are commonly encountered symptoms of FTLD. 1 Mendez et al. 1 suggested that FTLD subjects did not recognize their own behaviors as irrational. Moreover, if we hypothesized that the OCD symptoms were early symptoms of FTLD, this patient would have been expected to exhibit other symptoms of FTLD during the 10 years after the onset of the OCD symptoms at the age of 40 years. However, the patient showed typical OCD symptoms, except that they were late - onset in terms of age, and except that they worsened in severity, his OCD symptoms remained unchanged at least until the age of 53 years. Therefore, we consider it unlikely that the OCD symptoms that appeared at the age of 40 in this patient were symptoms of FTLD. Rather, in this case, we favor the proposition that the late-onset OCD in this case progressed to FTLD over 10 yeas. Although Tonkonogy et al. 5 reported a case of OCD developing Pick’s disease, this case developed Pick’s disease within the first 5 years after the onset of OCD at the age of 34 years.

To date, the clinical course of late-onset OCD remains unclear. A recent study of late-onset OCD 2 suggested that late-onset OCD might be characterized by specific pathological abnormalities in the brain. In this case, we could not observe any abnormalities associated with acute-onset OCD, such as either vascular lesions or brain tumors. Although we could not identify the age of onset of FTLD, we thought that this patient presented with typical clinical features of FTLD around the age of 56 years. Thus, we need to carefully observe both the etiology and the clinical course of OCD developing after the age of 30 years. The findings from this case may provide important clues to the presence of a common biological mechanism underlying both OCD and FTLD. Further study of the progression of late-onset OCD may provide valuable support to our contention in this case.