Status: Prohibited

History:

1970 - 2015: Failed attempts at decriminalisation and deprioritisation
2014: Legalisation of CBD (Cannabidiol) oil (although no way of legally obtaining CBD oil in-state)

Policy Framework:

• Possession of any amount is a misdemeanour, the punishment for which depends on prior possession offences. Possession for personal use is punishable by up to two years in prison and fines of up to $US6250;
• Distribution or cultivation is a felony punishable by up to 10 years in prison and fines of up to $US100,000.
  
  Source: Norml

Outcomes:

• Between 2005 and 2017, cannabis use disorder in people over the age of 12 decreased from 1.5% to 0.9%. 

Source: https://crime-data-explorer.fr.cloud.gov/explorer/state/iowa/crime