No catch-up growth in the DPRK and no signs of change either:
Recent refugees, scholars of North Korea and South Korean government officials see no signs that the economic hardships are pointing toward political instability. They see no existential threat to Kim Jong-il and his government, whether through civil unrest, political factionalism or a military revolt.
Humanitarian and ethical issues aside, you’d think a person would prefer to be the dictator of a China-style country with rapid economic growth than a North Korea-style one with mass impoverishment. Apparently PRC officials have tried to make this point in Pyongyang, but nothing much is happening.