SIR: Charles Bonnet syndrome (CBS) refers to complex visual hallucinations in psychologically normal people.1 Most individuals with CBS have decreased visual acuity.2 We recently examined a man who developed visual hallucinations consistent with CBS. The nature of his hallucinations changed markedly after he developed panic disorder, which caused him to seek psychiatric consultation.
Mr. I was diagnosed with pigmentary retinal dystrophy early in life. At age 30, he lost vision of his left eye due to a traumatic injury. At age 49, when the visual acuity of his right eye was at the level of sensus luminus, he began to report seeing vivid images, including familiar or unfamiliar human faces, downtown scenes in which many people were walking around, or theater scenes. He was not very concerned about the images, and could continue his job as a Shinto priest. At age 62, he began to experience spontaneous and recurrent periods of dizziness, discomfort and pain in the chest and forehead, and developed a fear of dying. As the attacks became more and more intense and frequent, he was brought to an emergency hospital, and thereafter consulted our psychiatric department. He was diagnosed with panic disorder. Neuropsychological testing did not demonstrate any gross cognitive impairment, and a brain CT scan was unremarkable. Interestingly, he claimed that the nature of his visual images changed drastically after he began to experience panic attacks. Complex visual hallucinations disappeared, and he began to see moving images of bars, spirals or spheres. These visual patterns evoked a sense of disgust in him, and during panic attacks the visual hallucinations increased in intensity. After medication with clomipramine 60 mg daily, the frequency and intensity of panic attacks were substantially reduced. Accordingly, his visual images became less disgusting and well-formed, such as scenery or humans. Disgusting images such as moving bars continued to appear during attacks, but with less intensity.
There are a limited number of case reports on successful pharmacotherapy for CBS, and most such reports describe the use of anticonvulsants.3,4 It is often the case that CBS does not annoy the patient. Thus, it is reasonable to consider pharmacotherapy only when visual hallucinations are associated with other psychiatric syndromes, such as panic attacks in the case of our patient.
Interestingly, the characteristics of visual hallucinations changed dramatically after our patient developed panic attacks. Complex visual hallucinations such as human faces or scenery were replaced by moving spirals, bars, or spheres. Recent neuroimaging studies demonstrated that particular types of visual hallucinations (e.g., color, texture, faces) are associated with activity in particular areas of the extrastriate cortex reflecting the functional specialization of the region.5 We suspect that intense anxiety modulated the spontaneous pattern of activation in the extrastriate cortex in our patient. Visual illusions or hallucinations are not regarded as common psychopathological features of panic disorder. However, under the condition of sensory deprivation, that is, without bottom up visual input, we speculate that spontaneously generated visual images could be easily modulated by the top down influences of intense anxiety.