SHINYANGA, March 27 -- FOR 40-year-old Ibrahim Seif, regret is not an occasional visitor it is a constant companion. It lingers in memories of a stable life that slowly unraveled, undone not by sudden misfortune, but by choices that seemed harmless at the time and devastating in hindsight.

A resident of Mwawaza Ward in Shinyanga Region, Mr Seif began using cannabis at the age of 30. At first, nothing appeared out of place.

He maintained his job, supported his family and continued his daily routines without disruption. For nearly five years, the drug seemed less like a threat and more like an invisible passenger present, but not yet steering the direction of his life.

In his words, cannabis “allowed him to remain himself,” a...