Zyclara is a topical medication and as such should have minimal systemic side effects. The most common side effects relate to local effects of irritation at application site.
There was no evidence of any psychiatric or psychotic side effects in the clinical trials. Since this was released onto general release then there are rare reports of agitation and depression, however we do not have evidence of a direct link.
Age 20 is a common age for new onset psychosis to develop, especially if there is any history of recreational drugs or alcohol. A full mental state examination by a psychiatrist would be needed, but it is less likely that a direct relationship could be established with this episode and Zyclara.