Table 4.

Characteristics of studies with heterogenous sample of participants.

Study	Study design	Sample size	Types of sample	Demographics of sample	Country	Diagnosis of sample	Method of diagnosis	Attention bias method	Outcomes
MIXED COHORT
Carpenter et al. (50)	Cross-sectional study	80 drug dependent individuals	All were illicit drug users enrolled in one of the six randomized trial combining coping skills relapse prevention and pharmacotherapy	62 males, 18 females 45 participants (cocaine), 25 participants (marijuana), 10 participants (heroin) Mean age 39.9 years	United States of America	Cocaine, Marijuana and Heroin dependence	DSM-IV dependence criteria Structured psychiatric interview	Drug Stroop Test	All groups had slower reaction times when presented with cocaine words.
Van Hamel et al. (51)	Cross-sectional	78 adolescents with substance dependence 64 healthy controls	Addiction care facility	Substance dependence group mean age 19.5 Control group mean age 19.0	Netherlands	Alcohol, Cannabis, Amphetamine or GHB Use disorder	Self-reported substance usage and severity of usage	Visual Probe task	Attentional bias for stimuli presented at 500ms and 1250ms. Higher severity of dependence, increased AB