i think trileptal came about before zyprexa had any fda approvals for bipolar and i think seroquel got its fda approval for bipolar in early 2000s. Back then there was no generic abilify either, and of course there wasnt newer stuff like caplyta, vraylar, latuda.
Still, the year 2000 is still quite some time ago if you think about it. If you were a practicing psychiatrist around that time period id imagine youd be 50s-60s now
By 2000:
Clozaril (1990 for schizophrenia), Zyprexa (1996 for schizophrenia, 2000 for mania), Risperdal (1993 for schizophrenia), and Seroquel (1997 for schizophrenia) had been around a rather long time.
There was also Depakote, approved in 1995 for bipolar disorder but used off-label for a long time before that. Tegretol technically was never FDA approved for bipolar disorder (Equetro was later), but it had been a mainstay of practice for the management of bipolar disorder since the 1970s. Lamictal came to the US in 1994 and used off-label for bipolar disorder until 2003 when the label was expanded.
In 2000 Trileptal didn't have an indication for any psychiatric disorder, and it still doesn't. It didn't have any studies supporting its use, and still doesn't have any great ones. Back in 2000 people were absolutely using all the atypical and many typical antipsychotics off-label for bipolar disorder.
In the years shortly after 2000a lot of options came out:
Geodon (2001 for schizophrenia), Risperdal was approved for mania, Seroquel was approved for bipolar disorder, and Abilify was approved for schizophrenia in 2002.
So for someone trained in 2000, there were many options with more reasonable use prior to Trileptal: every typical antipsychotic, lithium, Depakote, Tegretol, Lamictal, and 4 atypical antipsychotics.
In my room experience, people who trained prior to 2000 either have adamantly refused to prescribe Trileptal or gave in to the illegal marketing and pushing of the drug from their healthcare system to offer Trileptal on a misguided notion that it is lower risk than Tegretol. You probably do see plenty of psychiatrists who have been practicing for 20+ years prescribing it, but I highly doubt that it's because they were trained in 2000 to use Trileptal for bipolar disorder.