The patient was a 16-year-old Japanese male, with a normal birth history and normal developmental milestones. He was a high-achieving pupil, with no family history of psychiatric disorders. He had received his last diphtheria/pertussis/tetanus and measles vaccinations at the age of one and a half years, with no history of any significant health problems thereafter. When he was 15 years old, the patient began to develop a defiant attitude towards his father. He often stayed up late using the Internet and his school grades began to deteriorate. There were no prodromal symptoms at that time. At the start of the present illness, the patient developed easy fatigability with throat and foot pain. It was thought that the symptoms were related to a cold, and he attended school after taking medicines for common cold. Ten days later, however, he stopped eating and responding to others. Thereafter, after 2 days, he developed fever and quivered convulsively, and his parents took him to a neighborhood hospital. MRI of the brain was performed, and the T2-weighted and FLAIR images revealed high-intensity lesions in the subcortical white matter of the frontal lobes bilaterally, and in the left temporal lobe. These lesions on the T2 and FLAIR images could not be visualized on the T1 sequences. Cerebrospinal fluid (CSF) examination revealed the following: cell count 66/mm3 (monocytes 43/mm3), protein 41.5 mg/dl, glucose 81 mg/dl. Based on a suspicion of viral encephalitis, the patient was started on an antiviral drug and steroid pulse therapy. The second CSF examination revealed a cell count of 8/mm3 (monocytes 3/mm3), protein level of 25.9 mg/dl, negative results for oligoclonal bands and myelin basic protein, and normal levels of IgG and IgM. The patient’s level of consciousness improved the following day, and with the resolution of all the other symptoms a week later, he was discharged. The following month, the patient gradually stopped going to school and began to stay at home. He also refused to go to the hospital. A month later, his family managed to bring him to the Neurology Department of our hospital. After the initial examination, the neurologist recommended hospitalization for more detailed examination, however, the patient refused. The doctor then referred him to our psychiatry department. When he attended his first appointment, he was on a wheelchair. He did not answer any questions, keeping his head low and his eyes shut. Assessment on the Glasgow Coma Scale revealed a score of 4 for eye opening, 4 for verbal response and 6 for motor response, and it was not clear why he was refusing to talk or engage in conversations. With his parents’ consent, we decided to hospitalize him for closer examination. He did not resist, but he continued to refuse to communicate with the hospital staff even after hospitalization. He had no paralysis, no finger tremors, or any neck stiffness. The muscle tone and reflexes could not be clearly assessed, because the patient’s refusal to cooperate. He could eat and take care of his personal activities of daily living, although he was unwilling to take a bath daily. Rheumatologic disease, such as CNS lupus or vasculitis, was excluded, because the serological tests for antinuclear antibody, Rh factor, antimitochondrial antibody, proteinase-3 anti-neutrophil cytoplasmic antibody (PR3-ANCA) and myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) were negative. Other antibodies associated with some other forms of autoimmune encephalitis, e.g. anti-NMDAR and anti-voltage gated potassium channel antibodies, were not tested for. The same high-intensity lesions in the subcortical white matter as those seen a month earlier were still observed on the T2-weighted and FLAIR images on brain MRI. After admission, the patient isolated himself in his room and refused to talk, not only to the medical staff, but also to his own family members. We could not assess whether he suffered from disorientation and speech impediment, although he took his meals regularly and slept well. The electroencephalogram showed neither slow nor spike waves. We considered the possibility of disorganized schizophrenia, because of his disorganized behavior and speech, flat affect, and disturbance in behavior, communication and thought. We initiated treatment with risperidone, at a starting dose of 0.5 mg daily, which was gradually increased to 4 mg over a period of 4 weeks. Because there was no effect, however, we added aripiprazole at the dose of 6 mg daily for 2 weeks, however, this also had no effect on the patient’s symptoms. One month after admission, the patient began to speak gradually, and demanded to leave the hospital. When we explained the need for further assessment of his health status, he agreed, and an intelligence assessment, lumbar puncture, and single photon emission computed tomography (SPECT) were performed. SPECT showed slightly enhancing lesions in the anterior lobes, which were non-specific findings. CSF examination revealed the following findings: cell count 0/mm3, protein 18 mg/dl, glucose 64 mg/dl, IgG, IgA and IgM levels within normal limits. Examination by the Wechsler Intelligence Scale for Children—Third Edition (WISC-III) showed an above-average Intelligence Quotient (IQ). The patient was discharged from the hospital, but still tended to stay at home and absent himself from school. Even when he tried to attend school, he could not persist with it. At home, he took care of his personal activities of daily living, but could not sleep regularly and often became depressed. We increased the dose of aripiprazole to 12 mg daily and decreased the dose of risperidone to 3 mg for 2 weeks after discharge. We suggested continuing the antipsychotic drug treatment to him and his mother, but both disagreed and the treatment was stopped. Nine months later, he was unable to proceed to the next year of school and 2 years later, he quit high school. He was not sociable, and sometimes showed depressed mood. A repeat brain MRI at that point revealed no changes from the findings at the earlier imagings. However, thereafter, the patient gradually recovered, and about 2 years later, he passed the Certificate for Students Achieving the Proficiency Level of Upper Secondary School Graduates. During the entire course, the patient showed no evidence of auditory hallucinations, delusions or other symptoms suggestive of schizophrenia. Overall, his presentation remained stable during follow-up. The timeline is shown in Fig..