Of course, in India and most of the rest of Southeast Asia, their public health reporting systems are virtually non-existent. These kinds of third world countries have notoriously unreliable health statistics.
In countries without reliable or competent health care delivery mechanisms, its virtually impossible to say hat their rates of infection or affliction might be. IOW, how many "crazy uncle Pashtuns" are stuck in some closet someplace, never to receive even a moment of medical care?
Western countries have higher rates of behavior, or mental illnesses not because they "have higher rates", but because their health reporting systems are more robust and distributed, and the stigma that is associated with mental illness (or illnesses like Alz. that diminish mental capacity) doesn't exist. So, people are much more likely to get treatment, there's much more opportunity to get treatment, and once diagnoses is made and treatment is given, its more likely to be captured by the public health system.
Anyone with even a remedial understanding of how health care is delivered in India, knows that the statement "In India and Southeast Asia, it’s a rare disease.", is facially absurd and wholly unreliable.
Which, unfortunately, explains why we have the Left.