There are fashions and trends in diagnoses of mental conditions just like anything else. I’ve recently come to suspect that an especially fashionable diagnosis in Poland for young people is borderline personality disorder (osobowość chwiejna emocjonalnie typu borderline or zaburzenie osobowości typu borderline). A few months ago in the middle of class (on an unrelated subject) the topic of mental illness came up and within a minute a student had cheerfully announced that they’d been diagnosed with borderline personality disorder. I was very sceptical of this but changed the subject, probably back to some point about translation theory if I recall correctly.
A month or so later, during office hours a student allows that they have been diagnosed with borderline personality disorder. This time I simply said I didn’t believe the diagnosis (because I didn’t and don’t and the student seemed pretty unsure about it) and we went back to discussing the student’s assignment they had come to see me about.
Often, the answer to why some particular ailment is popular or fashionable in Poland can be traced to the popular Polish life strategy of solving problems through illness. I don’t think there are many other countries where so many problems can be solved by getting sick (more precisely by getting a medical professional to write a note to the effect that you’re just not up to whatever the cruel world wants you to do).
A person who suspects they’re about to be fired takes sick leave and their job is safe for as long as they can convince a doctor to keep writing up the notes. The only danger is when one sick leave ends and it’s time to hand in another (handing in a new sick leave notice before the letter of termination could be delivered became a delicate ballet needing exquisite timing).
A student who’s worried about passing an exam (which are separate from classes and inordinately important and unforgiving) can get sick and buy some time.
A young man (back when the draft existed) wanting to escape compulsory military service could get a sympathetic doctor to give medical reasons why they couldn’t possibly be expected to become a recruit.
Some time ago it was fashionable for high school students to be diagnosed with dysleksja (used as a cover term for any type of learning disorder and not the very specific condition of dyslexia). As it turned out the motivation here was easier conditions for high school leaving exams (also inordinately important).
It also might just be a fashion trend like celiac disease (starting to gain popularity in Poland). I’m not sure what’s going on with this, or if this was just two random cases and not a trend.