Dissociation and depersonalization are concepts with similar meanings.
I have encountered very sad stories where a psychiatrist confused dissociation with psychosis and prescribed antipsychotics to the patient completely unnecessarily, leading to long-term use with side effects such as weight gain. Moreover, the patient only experienced a one-time symptom, which did not even meet the diagnostic criteria for a disorder.
Professional publications even point out that the use of drugs may not be necessary even when the diagnostic criteria for the disorder are met. This is a rare mental disorder for which experts say to be careful with drugs and to consider whether they are needed at all.
Similar publications also state that sometimes the patient is scared that they have schizophrenia, while depersonalization is not nearly as serious a health condition.
Antipsychotics will never improve the symptoms of depersonalization. SSRIs are a better solution, especially for symptoms of accompanying anxiety.
Very high-quality research of all professional publications on the topic of depersonalization and the associated disorder is available on Wikipedia. Mandatory reading for psychiatrists and patients.
The reason why a psychiatrist may confuse depersonalization with psychosis is that depersonalization is one of the phenomena accompanying schizophrenic psychosis.
https://en.wikipedia.org/wiki/Depersonalization-derealization_disorder
https://en.wikipedia.org/wiki/Dissociation_(psychology)
https://en.wikipedia.org/wiki/Depersonalization