Ya ba are tablets containing a mixture of methamphetamine and caffeine.
DRUGS INC. (National Geographics Series)
It is a documentary provide great insight into the world of methamphetamine and Yaba.
Methamphetamine(aka Yaba in South Asia) is highly addictive, with many long-term users taking 5-10 pills daily. Post come-down effects include irritability, insomnia, confusion, tremors, convulsions, anxiety, paranoia, and aggressiveness. Hair loss can also be an indicator of a long-term user, either as a direct result of the drug intake, or indirectly through the user becoming withdrawn and anxious and contracting behavioral habits, such as hair pulling. Other reported symptoms also include lower back pain, possibly from damage to the liver or kidneys.