This is a comment I found in the internet. It reflects my own thinking.
The law makes no sense, they take away your license, job is on the line, etc. It would make sense if you are controlled/checked while STILL holding your driving license. And after a year of being controlled, there is no guarantee you (I) will pass the MPU, since they ask impossible questions. Then they send you to so many trainings (before, and after the MPU, if you do not pass) in order to get a "second chance" at an MPU.
I do not understand how is it that Germans take this without any resistance.
The MPU, or Medizinisch Psychologische Untersuchung, is a scandalous piece of legislation considered extremely suspect by Road safety and Psychology professional alike, and frowned upon by Brussels. Any Brit living here and who has a British License, which is valid for an unlimited time in Germany despite them preferring you to believe otherwise, would be advised to seek legal counsel. The problem, of course, is who do you ask? Germany are not famous for wanting you to know the truth, or granting you the rights afforded to you as members of the European Community. Also the naive posting above by Bipa is charming in its innocence. Not been here long, then?
It seems to me that the whole MPU thing is primarily a tool of social control, and secondarily a means of employing large numbers of barely competent Psychology graduates who wouldn't get a job elsewhere. There are no mechanisms to control the effectiveness of these tests, which are carried out behind closed doors, and the testers are accountable to nobody with respect to decisions reached, decisions which in some cases send very suspect signals and which can wreck lives. However MPU is good business. But for me the clincher is that despite some outrageous methods employed by the Traffic Authorities / MPU institutes, who work in cohorts, to bleed hundered of thousands of victims dry every year (where DOES all the money go?) using methods that are tantamount to demanding money with menaces, there has hardly been a bleat of protest from the population, who, being German, just roll over to take another kick.
As far as I know, nobody has taken this before the European courts of human rights, but, particularly in cases that involve drugs (remember NO evidence must be presented before a license is revoked pending MPU) there is a compelling case. I know personally someone who lost their entire livelihood because a disgruntled Policeman informed the Driving Authority that he suspected this person of being involved in drugs. This person then had to prove that he was drug-free for a year and waited two years to get his license back. No trial. No appeal. No information. Extortion. And he was and is completely drug free, but lost his job, house and almost his family. And because the germans will NEVER give you a level playing field (it's governed by Verwaltungsrecht, there are no effective ways of challenging or appealing decision, mechanisms that don't apply to this type of law!) there was nothing he could do. Trouble is, until the Germans get off their arses and challenge this, they'll just carry on getting milked. And us along with 'em.