But they can learn social skills. Remember that underachievers were thought to be motivated to fail in order to avoid scary future responsibilities. Likewise, some depressed people appear to fail in order to avoid people expecting them to do something in the future. This self-conning reduces their motivation to change. The other categories are pretty good self-help methods.
Several findings are of interest.
First, the students who were still lonely after seven months had tried the same behavioral and mental techniques as the students who had overcome their loneliness. The same cognitive characteristics found by other researchers. Second, the people who overcame being lonesome had developed more friendships, not necessarily more dating relationships although dating helps. Third, overcoming loneliness wasn't so much how many friendships one had make, more important was the quality and depth of the friendships. So, skills at getting intimate may be more important than skills at meeting people.