Table S6.

Cotwin control analysis of discordant heavy users in the MTFS on change in IQ

IQ subtestDiscordant Heavy Users
Nβ (95% CI)P
Vocabulary
 MZ and DZ47−1.5 (−5.5 to 2.6)0.481
Information
 MZ and DZ470.2 (−5.1 to 5.6)0.931
Block Design
 MZ and DZ47−1.6 (−7.3 to 4.1)0.584
Picture Arrangement
 MZ and DZ475.2 (−4.1 to 14.6)0.276
  • N represents the no. of discordant twin pairs in MZ and DZ groups. CI, confidence interval.