Background: Early substance use (SU) in adolescence is known to be associated with an elevated risk of developing substance use disorders (SUD); it remains unclear though whether early SU is associated with more rapid transitions to SUD. Objective: To examine the risk and speed of transition from first SU (alcohol, nicotine, cannabis) to SUD as a function of age of first use. Methods: N = 3021 community subjects aged 14–24 years at baseline were followed-up prospectively over 10-years. SU and SUD were assessed using the DSM-IV/M-CIDI. Results: (1) The conditional probability of substance-specific SU-SUD transition was the greatest for nicotine (36.0%) and the least for cannabis (18.3% for abuse, 6.2% for dependence) with alcohol in between (25.3% for abuse; 11.2% for dependence). (2) In addition to confirming early SU as a risk factor for SUD we find: (3) higher age of onset of any SU to be associated with faster transitions to SUD, except for cannabis dependence. (4) Transitions from first cannabis use (CU) to cannabis use disorders (CUD) occurred faster than for alcohol and nicotine. (5) Use of other substances co-occurred with risk and speed of transitions to specific SUDs. Conclusion: Type of substance and concurrent use of other drugs are of importance for the association between age of first use and the speed of transitions to substance use disorders. Given that further research will identify moderators and mediators affecting these differential associations, these findings may have important implications for designing early and targeted interventions to prevent disorder progression.

The CIDI is a fully standardised, structured interview for the assessment of psychiatric disorders according to DSM-II-R and proposed ICD-10 criteria. The development of this interview has been the collaborative effort of researchers from 18 sites around the world. In a field trial to test the cross-cultural acceptability and reliability of the questions, there was found to be high acceptance and excellent reliability for the substance use questions, problems with the lengthy alcohol section, and difficulties translating relevant substance use concepts into different languages. There is therefore room for further improvement in the substance-related questions. There proved to be differences between ICD-10 and DSM-III-R regarding substance abuse and dependence disorders.

The CIDI is a fully standardised, structured interview for the assessment of psychiatric disorders according to DSM-II-R and proposed ICD-10 criteria. The development of this interview has been the collaborative effort of researchers from 18 sites around the world. In a field trial to test the cross-cultural acceptability and reliability of the questions, there was found to be high acceptance and excellent reliability for the substance use questions, problems with the lengthy alcohol section, and difficulties translating relevant substance use concepts into different languages. There is therefore room for further improvement in the substance-related questions. There proved to be differences between ICD-10 and DSM-III-R regarding substance abuse and dependence disorders.

Background: Early substance use (SU) in adolescence is known to be associated with an elevated risk of developing substance use disorders (SUD); it remains unclear though whether early SU is associated with more rapid transitions to SUD. Objective: To examine the risk and speed of transition from first SU (alcohol, nicotine, cannabis) to SUD as a function of age of first use. Methods: N = 3021 community subjects aged 14–24 years at baseline were followed-up prospectively over 10-years. SU and SUD were assessed using the DSM-IV/M-CIDI. Results: (1) The conditional probability of substance-specific SU-SUD transition was the greatest for nicotine (36.0%) and the least for cannabis (18.3% for abuse, 6.2% for dependence) with alcohol in between (25.3% for abuse; 11.2% for dependence). (2) In addition to confirming early SU as a risk factor for SUD we find: (3) higher age of onset of any SU to be associated with faster transitions to SUD, except for cannabis dependence. (4) Transitions from first cannabis use (CU) to cannabis use disorders (CUD) occurred faster than for alcohol and nicotine. (5) Use of other substances co-occurred with risk and speed of transitions to specific SUDs. Conclusion: Type of substance and concurrent use of other drugs are of importance for the association between age of first use and the speed of transitions to substance use disorders. Given that further research will identify moderators and mediators affecting these differential associations, these findings may have important implications for designing early and targeted interventions to prevent disorder progression.