Table 3

Significance of correlations between cognitive functioning and level of substance use at the initial assessment and 1-year and 2-year follow-ups

Cognitive measure	Substance used; significance of correlation^*

	Alcohol	Cannabis	Cocaine	Stimulants	Hallucinogens
Verbal fluency
Category fluency	NS	NS, −0.21, NS	NS	NS	NS
Letter fluency	NS	NS	NS	NS	NS
Visual-spatial ability and motor speed
Digit symbol	NS	NS	NS	NS	NS
Trails A	NS, −0.29, NS	NS	NS	NS	NS
Memory
Immediate verbal memory	NS	NS	NS, NS, 0.29	NS	NS
Delayed verbal memory	NS	NS	NS, NS, 0.32	NS	NS
Immediate serial learning	0.20, NS, NS	NS	NS	0.14, NS,NS	0.14, NS, NS
Delayed serial learning	NS	NS	NS	NS	NS
Visual memory (Rey recall)	NS, 0.23, NS	NS	NS	NS	NS
Executive functioning
WCST categories	NS	NS	NS	NS	NS
WCST perseverative errors	NS	NS	NS	NS	NS
Trails B	NS, −0.22, −0.31	NS	NS	NS	NS
Visual attention (CPT)	NS	NS	NS	NS	NS
Early information processing (SPAN)	NS	NS	NS	NS	NS

Note: NS = not significant.
↵* Where there are 3 cell entries, the first refers to the first assessment data, the second to the 1-yr follow-up data and the third to the 2-yr follow-up data; p < 0.05.