Alcohol use frequently precedes breaks with reality - I have personally experienced it; what ought our public policy response be?
This story is another example of casual marijuana use triggering a mental illness in someone. The fact the user was 60 when he suffered his breakdown may be of significance (mental breaks are usually associated with much younger people), as would the regularity of his prior use and the potency of the drug he ingested.
Anecdotes about alcohol abuse aren't relevant to a discussion about marijuana and mental illness.