Every medication can have severe and permanent side effects, the question is how often that occurs for a particular drug, and how that stacks up against the quality-of-life improvement from taking that drug.
SSRIs are very bad, but antipsychotics are worse. There are many other reasons, but a demonstrative one is that there is a cumulative annual risk as high as 7% of developing a permanent movement disorder when on them.
It was really hard for my ex to have to choose between anti-psychs and the potential side effects, or exceedingly strong paranoia with incredibly lucid hallucinations - I did not envy her position