Is sluggishly progressing schizophrenia recognized outside of Russia?
The idea that schizo type disorders may onset slowly is commonly accepted in the West. We do not have a separate diagnosis for this type of onset in the DSM. Psychotic episodes may happen to individuals before they experience all the symptoms of bipolar or schizo type disorders.

It is common that a patient may begin to hear voices during isolated instances without the trouble with emotions. Then develop trouble with emotions. Then progress into hallucinations. The individual may cope with the isolated psychosis until the psychosis becomes so severe that they are unable to do without medical attention. This progression sometimes takes years.

It is possible that any diagnosis of mental illness can be used for political reasons though.