Testing the validity of national drug surveys: comparison between a general population cohort and household surveys.

"alspac participants reported their lifetime and past-year use of cannabis and other illicit drugs (supporting information data s1 appendices1 and 2 ).; any participants who responded 'no use' to all of these drugs or who had reported no use for 9 of 10 of the full complement of alspac drug items (supporting information data s1 appendix 1 ) but had missing data for one remaining item were coded 'no use'.; in the csew participants reported on lifetime and past-year use of cannabis and 11 other drugs (supporting information data s1 appendices1 and 2 ).; details are provided in supporting information data s1 appendix 3 .; table 2 prevalence comparison of drug use between alspac and the csew past-year drug use lifetime drug use alspac weighted 3389 % (95% ci) csew weighted 1129 % rd% (95% ci) p value alspac weighted 3389 % (95% ci) csew weighted 1146 % rd% (95% ci) p value any illicit drug use 36 7 (35 0-38 6) 16 4 (14 3-18 7) 20 3 (17 6-23 0) p <= 0 001 62 8 (61 1-64 6) 40 6 (37 8-43 5) 22 2 (19 0-25 5) p <= 0 001 amphetamine 17 0 (15 7-18 4) 1 1 (0 6-1 9) 15 9 (14 5-17 3) p <= 0 001 32 9 (31 2-34 7) 8 1 (6 6-9 8) 24 8 (22 6-27 0) p <= 0 001 anabolic steroids a 0 4 (0 01-1 0) - a 1 3 (0 7-2 1) - cannabis29 2 (27 5-31 0) 13 8 (11 8-15 9) 15 4 (12 9-17 9) p <= 0 001 60 5 (58 7-62 3) 37 3 (34 5-40 2) 23 2 (20 0-26 4) p <= 0 001 powder cocaine 19 6 (18 2-21 2) 4 8 (3 6-6 2) 14 8 (13 0-16 6) p <= 0 001 30 8 (29 1-32 6) 13 9 (11 9-16 0) 16 9 (14 4-19 4) p <= 0 001 crack cocaine 0 2 (0 0-0 5) 0 0 (0 0-0 3) 0 2 (0 0-0 4) p = 0 127 1 0 (0 6-1 7) 0 9 (0 4-1 6) 0 1 (-0 5-0 7) p = 0 764 ecstasy b 3 6 (2 6-4 8) - b 11 1 (9 3-13 0) - hallucinogens7 3 (6 4-8 3) 1 5 (0 9-2 4) 5 8 (4 7-6 9) p <= 0 001 18 1 (16 7-19 7) 6 8 (5 4-8 4) 11 3 (9 3-13 2) p <= 0 001 inhalants0 7 (0 5-1 2) a - 2 6 (2 0-3 3) a - injecting drug use 0 2 (0 0-0 4) a - 0 3 (0 2-0 6) a - ketamine b 1 1 (0 6-1 9) - b 5 1 (3 9-6 5) - mephedrone b 0 4 (0 1-1 0) - b 5 4 (4 2-6 9) - nitrous oxide 20 6 (19 2-22 1) a - 45 6 (43 8-47 5) a - opioids2 7 (2 2-3 3) 0 0 (0 0-0 3) 2 7 (2 2-3 2) p <= 0 001 5 0 (4 2-5 9) 0 9 (0 4-1 6) 4 1 (3 2-5 0) p <= 0 001 sedatives/tranquilisers5 8 (5 0-6 7) 1 1 (0 6-1 9) 4 7 (3 7-5 7) p <= 0 001 11 6 (10 4-12 9) 3 5 (2 5-4 7) 8 1 (6 6-9 6) p <= 0 001 alspac = avon longitudinal study of parents and children; csew = crime survey for england and wales; rd% = risk difference % (alspac as comparator) a no equivalent in this sample b included in another category in this sample (see supporting information data s1 appendix 1)."

"Declaration of interests There are no declarations of competing interests."

"Funding The UK Medical Research Council and Wellcome (102215/2/13/2) and the University of Bristol provide core support for ALSPAC. This publication is the work of the authors and H.C., J.H., M.H., J.B. and L.H. will serve as guarantors for the contents of this paper. CRUK‐funded (C1417/A22962) Smoking and Alcohol Toolkit Study for sharing data on prevalence of smoking and hazardous drinking in England. The work was undertaken with the support of The Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), a UKCRC Public Health Research Centre of Excellence. Joint funding (MR/KO232331/1) from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the Welsh Government and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. We also acknowledge funding from the NIHR School of Public Health Research, NIHR Health Protection Research Unit in Behavioural Science and Evaluation and NIHR BRC at Bristol. The MRC and Alcohol Research UK (MR/L022206/1) funded data collection and also supports J.H. L.H. is funded by The Wellcome Trust."