However, having performed research myself I can first tell you 1000 people in one country (BBC link) with vaguely defined operational variables and lack of true randomization this study is no better than the meta analysis performed by Lancet a few years back where they found the first causal link between marijuana use and schizophrenia in persons without a family history of the disease.
As someone who has smoke plenty of pot over many years and written a Brain and Behavior paper (15 pages) on the effects of marijuana on the nervous systems and other systems-- there can be temporary short term memory loss and munchies
A small subset of people with schizoid tendencies or schizophrenia and certain other mental disorders can be more susceptible to paranoia and it is also environment dependent. Do not trust the environment you are in and getting high may amplify that.