Yes, since the beginning of society, there has been moral problems and this goes back to parenting and parents working to better themselves. It is just that society as a whole has gotten worse as there are more and more people roaming on the face of the earth having not many morals and values.
At this juncture, I am sure people are trying to gather information about Mr. Lubitz and his childhood. In one article, it said, "But Lubitz, an avid runner with a passion for aviation, seemed normal when her daughter saw him just before Christmas, she said, adding that he was a 'lovely boy' with a 'good family background.'" So hence, at this time, his childhood is shrouded in mystery as it yet has to be defined how good of a family background he had.
I just believe that Mr. Lubitz himself made a conscious decision to turn to medication to "cure" his depression, but this turned out for the worse. Yes, I believe he was sane enough to be aware of his heinous crime and sin of premeditated murder. Data from one of the black box showed that Mr. Lubitz was breathing, but not answering the frantic actions of the pilot when he was attempting to break down the cockpit door. He was aware of all the actions he made, including pressing the button to make the plane descend. It was said by an airline expert that the button that controls the descending cannot be pressed if the body was slumped over the control as it has to be deliberately pushed.
Yes, problems can occur when people are off their medication because there was a chemical imbalance to begin with and it spirals out of control when there is no medication to revert it to its original chemical imbalance.