analysis - Why were the parents in The Poltergeist shown smoking pot and drinking?

Early in the movie, director Tobe Hooper shows both parents smoking pot in their bedroom while their son Robbie is spooked by a menacing tree outside his window.

Later, after the incidents start to get worse (and the team of parapsychologists from UC Irvine comes to investigate the phenomena), both Steve and Diane are seen drinking - even Dr. Lesh, the team-lead participates.

Why were these characters shown smoking pot and drinking? What was Tobe Hooper trying to achieve by doing so?

Answer

The filmmakers portray characters in specific lights to enhance the purity of Carol Ann.

• Diane and Steven are shown to be impure by their

  
  
  
  
  1. Marijuana usage
  
  
  2. Consumption of alcohol, arguably excessively, when faced with the true force of the poltergeist
  
  
  3. Their handling of their problems by yelling, screaming, reacting before thinking (Ex: Diane and Steve running around the house both inside and out trying to save Robbie and ignoring Carol Ann, leaving her at the mercy of the poltergeist to capture her.
  
  



• Dana is a reflection of her mother, evidenced by Diane's pleased reaction to Dana dealing with construction workers whistling at her by flipping them off in a sassy way (and more subtly, when Dana is up late on the phone-- possibly talking to a boy). In addition both Diane and Dana have similar names and dark hair in contrast to Carol Ann's different name and pure blond locks.



• Robbie is an instigator, always starting fights with Carol Ann, though not necessarily in a mean-spirited way-- more playful than anything else.


• Carol Ann never speaks loud or defiantly, never cries or screams, embodying a more peaceful and angelic demeanor to the slightly more chaotic (read: normal) rest of the family.

@DavidStratton makes an excellent point regarding the normalcy of the family being expressed by their use of marijuana and alcohol that absolutely applies here. But to be clear, it only applies to Diane, Steven, Robbie and Dana-- not Carol Ann. She is not normal: she is special, pure, better. Even Robbie, who is a close second to Carol Ann in regard to how pure her character is, can never match her. Which is why he was sucked into the darkness in the evil tree outside the house, while Carol Ann was brought closer to the light.

To sum up: Steven and Diane are shown smoking pot to portray them as a typical couple of grown-up-hippies (even reaching for a biography of Ronald Reagan to further assimilate to their new world of conservative homogeneity) just trying to raise a family-- in addition to raising Carol Ann up on to a pedestal of purity to show us, the audience, just why the poltergeist wanted her and not them.