Parable of the Sower by Octavia E. Butler

The time is 2025, the place is California,  where small walled communities must protect themselves from horrors of desperate scavengers and roaming bands of people addicted to a drug that activates an  orgasmic desire to burn rate in murder when one small community is overrun 15 year-old Lauren Alameda with the hereditary Trait of hyper empathy, which causes her to feel others pain as her own set off on foot along the dangerous coastal highway is moving north into the unknown.