Table 6.

Substance use disorder: Retrieved studies and their main outcomes.

Study	Country (region)	Data	Psychiatric disorder	Symptoms investigated	Assessment technology	Sample, n	Data collection time	Statistics	Synthesis of main results
Epstein et al [37], 2020	Baltimore (United States)	2020	Substance use disorder	Environmental exposure	Passive (smartphone): GPS Active: questions on level of craving from heroin, cocaine, and stress level	189	Period of collection: 16 weeks Frequency of collection: passive (every 15 or 20 min) and active (at least 23 times weekly)	Overall accuracy in predicting absence of drug or stress craving=0.93% Overall accuracy in predicting presence of drug or stress craving=0.7%	The machine learning models used correctly predicted the occurrence of drug or stress craving 90 min in advance with a very good overall accuracy at the end of 16 weeks.