I also wouldn't say (although I'm not an expert) that most "tulpa" cases are a disorder or a mental disorder because by definition a mental disorder has to impair or interfere with personal functions. However the symptoms are very similar with that of DID and certainly many psychiatrists could diagnose it as such. Regarding the self induced part, it is possible to self induce many mental illnesses such as depression or psychoses. To be fair it is not clear if it is possible to self induce DID (and "tulpas" probably don't fall under the criteria of DID under DSM-5). There are many cases though where people who might think that they hear voices or see weird things give themselves a false diagnosis and by trying to look out for the symptoms get real psychosis. BUT all of that doesn't even matter because what I said was a meme.