"A new study by sociologists at the University of Maryland concludes that unhappy people watch more TV, while people who describe themselves as very happy spend more time reading and socializing."
But in the next paragraph makes the cause -> effect leap:
"Analyzing 30-years worth of national data from time-use studies and a continuing series of social attitude surveys, the Maryland researchers report that spending time watching television may contribute to viewers' happiness in the moment, with less positive effects in the long run."
I'm not sure what the actual study says, but in my experience it's very much a correlation: unhappy people watch large amounts of TV to escape reality.