EDINBURGH — The sheer quantity of shows at the Edinburgh Fringe makes it a fascinating barometer of the times. For almost a month, the dedicated theatergoer can see four or five productions a day — this critic’s personal tally for August is upward of 50 — and out of this cultural overkill, patterns start to emerge.You can speculate about the psychological reasons — fear of the credit crunch, worries about global warming, international unrest? — but something has turned the theatrical mood very sober in 2008. This was initially apparent at the Traverse Theater, the city’s home of new writing, where even the least political work had a dark undertow. Opening week highlight was “Deep Cut,” a verbatim drama by Philip Ralph, produced by Cardiff’s Sherman Cymru, that considered the case of Pvt. Cheryl James, one of four soldiers to die in mysterious circumstances while on duty at England’s Deepcut military barracks. By combining the emotional response of her parents with the political ramifications of the case, Ralph created a play that was both moving and polemical. The piece set the tone for a program that included Zinnie Harris’ “Fall,” about post-war reconciliation; Simon Stephens’ “Pornography,” about the terrorist bombing of London in 2005; and “Architechting,” by Gotham’s the Team, about Deep South racism. Even less obviously political work, such as Enda Walsh’s brilliant and surreal “New Electric Ballroom” and Mark O’Rowe’s compelling “Terminus,” were brooding and intense. The exceptions at the Traverse were Daniel Kitson’s “66a Church Road,” a hilarious monologue about nostalgia for his former apartment; “Slick” by Glasgow’s Vox Motus, a cartoon caper with half-lifesize puppets; and “Once and for All We’re Gonna Tell You Who We Are So Shut Up and Listen,” by Belgium’s Ontroerend Goed, an infectious celebration of teenage energy tipped to transfer to UCLA Live. Serious themes were apparent all over the Fringe, characterizing many of the fest’s prize-winners, with subjects ranging from deprivation in a South African township (“Itsoseng”) to life on the Iraqi frontline (“In Conflict”) to sex trafficking in the U.K. (“In a Thousand Pieces”). Winning the Carol Tambor Award and a January run at Gotham’s PS122 was “Eight,” a series of monologues by recent graduate Ella Hickson, who showed a keen awareness of the connection between the personal and the political. The inaugural Holden Street Theaters Award went to “The Tailor of Inverness” by Matthew Zajac, who forged a heartfelt link between the story of his father and the great displacement of WWII. It wasn’t a great year for foreign theater, although a new venue, the World at St. George’s West, did an impressive job of bringing feel-good shows with a social conscience from Brazil, Cuba, Cambodia and Tanzania to the city. The big hitters from abroad arrived courtesy of the concurrent Intl. Festival, which was in as serious a frame of mind as the Fringe. Jonathan Mills’ second program included a powerful poem to suicide in the form of Sarah Kane’s “4.48 Psychosis” by Poland’s TR Warszawa, the same company that brought a holocaust-inflected “Dybbuk.” Belgium’s Muziektheater Transparant considered the morality of collaborating with the Nazi occupying forces in “Ruhe,” while both Sarajevo’s East West Theater Company in “Class Enemy” and the National Theater of Scotland in “365″ put the lives of disenfranchised teenagers centerstage. By contrast, the superficial fantasia of Matthew Bourne’s “Dorian Gray,” an orgy of death and decadence, seemed like light relief.