The source you pulled out mentioned khat only a few times and only briefly, whereas they were going more in depth with other reasons such as "post war trauma" and went more un depth on that
There was nothing exposed, all these researchers did was explain the lack of mental health facilities in the region, explained social stigmas around mental health in the community, and explained why it is an issue, and the reason why was less about khat than your buddy
@sincity would like you to know (khat is still a problem) none of these challenges are unique to Somaliland, this is a problem among all Somalis