Do newly hired professors have to take a drug test before they start?

Is this a serious question? I would refuse to work anywhere where my employer would require me to do such a test. It is simply none of their business.

I am actually not aware of any (European) university that would require anyone to take a drug test. In fact, it would be illegal in many countries to do this (or at least, there are very strict rules about the circumstances in which it would be legal).

In Germany you will be subjected to a medical examination if you become a civil servant. Full professors (W3) are typically civil servants. The levels below that (W1 and W2), are typically also civil servants, though not permanent and the examination tends to be a bit easier. Post-docs (TVL 13 or 14) are typically "normal" employees, and those are not subjected to the examination.

I believe that it is in principle possible to refuse the civil servant status and become a professor as a normal employee, and thus avoid the medical examination. However, I don't know of anyone who has done so voluntarily as the financial benefits of civil servant status are substantial (job security, lower tax rate, better pension).

While drug testing is very common in the USA, this is not the case world wide. In the UK it is rare. The uk government advises

Employers should:

• limit testing to employees that need to be tested
• ensure the tests are random
• not single out particular employees for testing unless this is justified by the nature of their jobs

Workers can’t be made to take a drugs test but if they refuse when the employer has good grounds for testing, they may face disciplinary action.

Part of the difference is that trade union membership is much higher in Europe, particularly in white collar jobs, such as teaching.

The Trade Union congress notes that it drug tests are rare in the uk, outside of transport and energy generation.

It further notes that in many European countries, pre-employment testing is not allowed, however in the UK the law is less clear. Employment tribunals have established that possession of drugs outside the workplace cannot in itself be grounds for dismissal. There must be evidence of impairment.

This implies that a university lecturer would not be asked to provide a sample for drug testing prior to employment, nor during employment nor prior to gaining promotion, since a univiersity would not be able to convince an employment tribunal that such testing is needed.