Alcohol use	FJAL1000, FJAL1050, FJAL1100, FJAL1150, FJAL1350, FJAL1400, FJAL1450, FJAL1550, FJAL1900, FJAL1950	Frequency YP has a drink containing alcohol	Scores of 8 or more as an indicator of hazardous/harmful drinking	17.5 years
		Number of drinks containing alcohol YP has on a typical day
		Frequency YP has 6 or more drinks on one occasion
		Frequency YP was not able to stop drinking once started, in past year
		Frequency YP was unable to do what was normally expected of them due to drinking, in past year
		Frequency YP has needed a first drink in the morning to get them going after a heavy drinking session, in past year
		Frequency YP has had a feeling of guilt or remorse after drinking, in past year
		Frequency YP has been unable to remember what happened the night before because they had been drinking, in past year
		YP or someone else has been injured as a result of YPs drinking
		Relative or friend or doctor or other health worker has been concerned about YPs drinking or suggested they cut down
Smoking	FJSM050	YP has ever smoked a whole cigarette	Any weekly smoking	17.5 years
	FJSM250	YP has smoked cigarettes in the past 30 days
	FJSM450	(SMOKE EVERY WEEK)
Cannabis use	FJDR1000, FJDR1050, FJDR1100, FJDR1150, FJDR1200, FJDR1250	YP has ever used cannabis before midday, in the past 12 months	A score greater than 1	17.5 years
		YP has ever used cannabis when they were alone, in the past 12 months
		YP has ever had memory problems when they used cannabis, in the past 12 months
		YP has friends or family members tell them they ought to reduce their cannabis use, in the past 12 months
		YP has ever tried to reduce or stop their cannabis use without succeeding, in the past 12 months
		YP has ever had problems because of their use of cannabis (argument/fight/accident/bad result at school etc.), in the past 12 months
Illicit drugs	FJDR5050	YP has tried cocaine in the last year	Any drug use	17.5 years
	FJDR5200	YP has tried amphetamines in the last year
	FJDR5350	YP has tried inhalants in the last year
	FJDR5500	YP has tried Sedatives or Sleeping Pills in the last year
	FJDR5650	YP has tried Hallucinogens in the last year
	FJDR5800	YP has tried Opioids in the last year
	FJDR5950	YP has tried other substance in the last year
Covariates/confounders
Occupational social class	C755/C765	The highest of paternal/maternal occupational social class was used	Manual/non-manual	Antenatal
Maternal age at birth	e695	Age of mother at birth		Antenatal
Maternal education	c645a	Mums highest ed qualification	CSE/none/Vocational	Antenatal
			O level
			A level/Degree
Economic hardships/problems	b594	Major financial PROB since PREG	Yes/No	Antenatal
	c525	Financial difficulties (scores greater than 6 on the financial difficulties scale were coded as experiencing difficulties)	Scores above 6 were taken as a sign of financial difficulties
Maternal drug/alcohol use		FAI drug sub scores – substance use in the first 4 years after pregnancy	0–4 years	Antenatal-4 years
Maternal Smoking	j735	Number of cigarettes smoked a day	Yes/No	4 years
Child sex assigned at birth	KZ021		Male/Female	At birth
Marital status	a525	PRES marital status	Married/Single	Antenatal
Housing status	g352	Home rented or owned	Rented/owned	1.5 years old
Maternal stressful life events	e445	Total stressful life events		Antenatal
Maternal depression	b370	EPDS depression score		Antenatal
Maternal anxiety	B351	Crown-crisp anxiety score		Antenatal
Auxiliary variables
Smoked cigarettes	fg4822	Teenager has smoked cigarettes	Yes/No	13.5 years old
Alcohol use	fg4872	Teenager has drunk alcohol without parents’ permission	Yes/No	13.5 years old
Cannabis use	fg5422	Teenager has tried cannabis	Yes/No	13.5 years old
Offered drugs	fg5500	Teenager has been offered drugs	Yes/No	13.5 years old