“A Viral Infection of the Mind? The Curious Case of Encephalitis Lethargica”, 2011-10-12 (; similar):
But the illness provoked a flood of publications throughout the 1920s and 1930s, as its kaleidoscopic combination of neurologic and psychiatric phenomena provided insights into brain function that had previously been the subject of speculation. These insights have had an enduring impact upon both neurology and psychiatry.
…The psychiatric facets of this phase were no less important. A peculiar lack of internal drive separating the patient from their world was typical. Despite normal intelligence, these patients could not summon the will power to execute their wishes. More insightful sufferers described how neither their perceptions nor their own thoughts were associated with the required emotional content that permitted exercise of their will. Patients could appreciate that a pianist played with great technical skill, for instance, but no longer sensed the beauty of the music…The only consolation was that this same apathy often meant the sufferers were not overly depressed by their illness or by the prospect of a life in an institution (remembering that these young patients might live for another half century or more).
…The second phase was marked by a general loss of concentration and interest in life, giving a vague sensation that the patient was not the person they had once been. But this period, which resembled chronic fatigue syndrome, was the calm before the storm. Unbeknownst to the victim, localized neurodegeneration proceeded apace through the first phase, and after an interval—lasting between a few days and 30 years—post-encephalitic parkinsonism (PEP) emerged. Unmistakable and irreversible, PEP consigned the young sufferers (mostly 15–35 years of age) to decades of disability. For those who had not yet passed adolescence, the second period was marked by pathologic changes of character that approached the psychopathic.
Younger children, 5–10 years old, might merely irritate with their clinginess; their impaired concentration; their incessant restlessness and need for noise; and their lack of consideration for others—not unlike current attention deficit disorders. But as they grew in strength, their incorrigible impulsiveness escalated in violence and they posed a danger to themselves and others. Errant behaviors included cruelty to anyone who crossed them; destructiveness; lying; and self-mutilation including, in one example, removal of eyes. When they reached adolescence, these patients manifested inappropriate and excessive sexuality, including sexual assault without regard for age or gender. Bizarrely, these children were driven by impulsiveness, not self-interest. Thefts, for example, were not undertaken for personal benefit and stolen goods were often immediately forgotten, or given away. Patients often expressed genuine remorse for their actions, explaining they recognized their wrongdoing but had been compelled to act as they did.
Some children improved after adolescence, but in many the only brake on their bad behavior was the parkinsonism that developed as they entered adulthood. Those not confined to hospital with parkinsonism often proceeded to a life of habitual criminality—mostly theft in men, prostitution in women, but also ranging up to rape and murder.
This phenomenon encouraged many countries to re-examine laws regarding legal responsibility in those whose actions were curtailed neither by encouragement nor prison, but who nonetheless maintained a sense of what was socially appropriate.