Table 2.

Implementation of matching criteria by studies of antipsychotic-naïve individuals with psychosis vs. healthy controls.

Author	Age		Gender		Parental SES		Cognitive Outcome UnTx IWP vs Healthy Controls
	Matched	Statistically Controlled	Matched	Statistically Controlled	Matched	Statistically Controlled
HIC
AP Naïve IWP vs HC
Arnado and Olié (2006)	✓						1
Andersen et al. (2013)	✓		✓		✓		1
Anhøj et al. (2018)	✓		✓		✓		2
Anilkumar et al. (2008)	✓		✓				2
Boksman et al. (2005)		✓		✓			1
Brickman et al. (2004)	✓		✓				1
Hill et al. (2004b)	✓	✓	✓	✓	✓	✓	1
Krieger et al. (2005)	✓		✓				1
Kruiper et al. (2019)	✓		✓		✓		1
Schérer et al. (2003)		✓					1
van Veelen et al. (2011)		✓	✓				1
Chan et al. (2006)		✓					2
Fagerlund et al. (2004)	✓		✓				2
Salgado-Pineda et al. (2003)	✓		✓		✓		2
Harris et al. (2009)		✓		✓			2
Hill et al. (2004a)	✓		✓		✓		2
Hilti et al. (2010)		✓		✓			2
Levitt et al. (2002)		✓	✓		✓		3
Nejad et al. (2011)		✓		✓		*	3
Forest et al. (2007)							3
Sum (HIC n = 20)	11	9	12	5	6	2
LMIC
Chen et al. (2014)	✓		✓				1
Guo et al. (2014)	✓		✓				1
He et al. (2013)	✓		✓				1
Hu et al. (2011)	✓		✓				1
Huang et al. (2017)	✓		✓				1
Liu et al. (2018)		✓		✓			1
Lu et al. (2012)		unclear		unclear			1
Wang et al. (2007)		*		*			1
Wu et al. (2016)		*		✓			1
Xiu et al. (2016)		✓		✓			1
Zhang et al. (2013)	✓		✓				1
Zhang et al. (2015)		✓		✓			1
Xiao et al. (2017)	✓		✓				2
Emsley et al. (2015)	✓		✓				2
Huang et al. (2016)	✓		✓				2
Man et al. (2018)		*		✓			2
Sum (LMIC) (n = 16)	9	3	9	5	0	0
Overall Sum (HIC & LMIC)	20	12	21	10	6	2

HIC = High Income Countries

LMIC = Low- and Middle-Income Countries

SES = Socio-economic Status

- not applicable

^*significant differences reported by age, gender, or parental SES

✓ matched to the extent possible

unclear = matching unclear, states patient ‘similar by’ gender, age, or parental SES.

1 = IWP worse cognitive function vs Healthy Controls.

2 = some comparisons show IWP worse cognitive function vs. Healthy Controls; and some comparisons show no significant differences between groups.

3 = No comparisons show IWP worse cognitive function vs. Healthy Controls (all findings nonsignificant).