What survives
That dreams track waking concerns is supported, and that recording them preserves material that would otherwise be gone within minutes is trivially true. A dream journal is a real instrument for noticing what a period of your life was actually about.
What does not
That a given symbol has a fixed meaning transferable between dreamers. No study supports it, the continuity research points the other way, and the oldest surviving practitioner of the art — Artemidorus, second century — was already arguing against it.
Aserinsky and Kleitman (1953)
Science
Tested Whether eye movement during sleep marks a distinct state associated with dreaming
Found REM sleep identified; dream recall far higher when woken from REM
Since Yes, universally. This is settled physiology.
Hall and Van de Castle (1966)
The Content Analysis of Dreams
Tested Whether dream content shows stable, quantifiable regularities across people
Found Strong and stable norms for characters, settings, emotions and aggression; differences by sex and age that replicate across cultures
Since Yes, in large corpora including the DreamBank archive
Schredl and Hofmann (2003)
Consciousness and Cognition
Tested The continuity hypothesis — that dream content tracks waking concerns
Found Waking activities predicted dream content, most strongly for emotionally intense concerns
Since Broadly, yes, though effect sizes are modest and the mapping is not literal
Wamsley and Stickgold (2011)
Current Biology
Tested Whether dreaming of a learned task improves later performance on it
Found Participants who dreamed of the maze task improved roughly ten times more than those who did not
Since The memory-consolidation role of sleep is well supported; this specific finding less so
What would change this rating
A pre-registered study showing that blind raters, given only a dream report and a dictionary, can identify a dreamer's waking circumstances better than chance. That study has not been run and would settle the question in one direction or the other.
A rating that no possible finding could
alter is an opinion. Every volume names the result that
would move it.