FORT CARSON, COLO. (AP) -- A baby-faced, chain-smoking infantryman is the latest challenge to the Army as it struggles to address mental health problems in its ranks while fighting two wars.

Twenty-year-old Pfc. David Lawrence is accused of fatally shooting a jailed Taliban member in southern Afghanistan. He's charged with premeditated murder and could face execution if convicted.

Lawrence was taking antidepressants and a sleeping aid at the time. Family members say he told them he was hearing voices, and he checked in to a mental health center last week.

His case comes amid rising numbers of suicides, PTSD cases and traumatic brain injuries in the military. At the same time, commanders are striving to maintain the Army's numerical strength and soldier discipline in the face of repeated deployments.

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