Well, if you ask me, i think the following three are the root cause of all other problems.

Illeteracy
Population pressure
Unemployment

For example, drug-use and crime can be linked to unemployment and religious extermism and gender descrimination may be due to illeteracy, similary, the poverty and lack of social services can be traced due to over-population.
Infact, the problems u mentioned are inter-linked and need an holistic view to understand them.