The evidence is clear that children often suffer enormously when their parents misuse drugs and alcohol. A child with a parent who engages in hazardous drug or alcohol use is:

• more than twice as likely to experience an accidental poisoning[1]
• more than 1.5 times more likely to develop a conduct disorder[2]
• more than 2.5 times more likely to misuse drugs and alcohol in adolescence and adulthood.[3,4]

During infancy, the risk of severe harm is even greater. Maternal drug or alcohol misuse during pregnancy more than doubles the risk of death during infancy[5] and is disproportionately represented in serious case reviews.[6]

The evidence is also clear that parental substance misuse is highly prevalent. Recent estimates show that over a fifth of all children have a parent who engages in hazardous drug or alcohol use on a regular basis, and 12% of infants live with at least one adult who has an alcohol use disorder.[7,8]

The evidence is less clear, however, when it comes to understanding how to respond to adult substance misuse problems. While a variety of treatments exist, systematic reviews consistently conclude that the quality of their evidence is moderate at best.[9]

• Interventions with stronger evidence for improving adult outcomes include a variety of pharmacological treatments, behavioural couples therapy and cognitive behavioral therapy combined with motivational interviewing.[10]
• Interventions with less evidence include Self-Management and Recovery Training (SMART Recovery) and 12-step programmes.[11,12]
• Historically, brief interventions providing advice for reducing substance misuse have been judged as having good evidence. However, more recent studies suggest otherwise. A 2015 systematic review concluded that brief interventions do not consistently reduce alcohol consumption among dependent drinkers, nor do they improve access to effective treatment.[13] A Cochrane update published earlier this year judged the evidence for improving outcomes for harmful drinkers to be moderate.[14]
• Little is also known about the efficacy of interventions provided to pregnant women.[15]

Most importantly, very few studies have considered the extent to which interventions provided to substance misusing parents also improve outcomes for children. While some studies consider whether interventions reduce child maltreatment risk, very few consider their impact on other important child outcomes.[16] Given the negative impact parental substance misuse has on all aspects of children’s health and wellbeing, our research has highlighted this as an area where the evidence is significantly lacking.

So, what can be done to improve the evidence base?

First, many of the evaluations investigating the efficacy of adult substance misuse treatments are not robust enough to attribute causality to the intervention model. We therefore need more studies meeting EIF’s level 3 threshold to determine whether these interventions are actually making a difference.

Second, the majority of studies conducted to date primarily consider reductions in the amount of substances consumed, but fail to consider other important outcomes, such as reductions in family conflict or improvements in parenting practices. We therefore believe that future studies consider the wider benefits of substance misuse programmes in addition to those associated with drug and alcohol use.

Third, we know that relatively few individuals with a substance misuse problem actually receive any substance misuse treatment. For example, a recent analysis of drug and alcohol treatment use in England showed that less than 20% of dependent drinkers were receiving any treatment.[17] In this respect, studies consistently show that substance misuse problems are among the most undertreated mental health problems in developed countries.[18]

Fourth – and most crucially – studies should systematically consider how children benefit from the drug and alcohol misuse treatments offered to their parents. Child benefits should obviously include reductions in child maltreatment risk, as well as other impacts associated with their wellbeing more generally:

• for older children, relevant outcomes include reductions in behavioural problems and adolescent substance misuse
• for younger children, including infants and toddlers, relevant outcomes include increases in children’s attachment security and improvements in their health and development.

Given the negative impact parental substance misuse has on children, we believe the lack of evidence involving interventions for parents who misuse drugs and alcohol represents a serious gap in the evidence base. We therefore recommend that more high-quality studies be urgently commissioned to reduce this gap, so that the benefits of these interventions for children are better understood.

Notes

1. Tyrrell, E.G., et al. (2012). Children at risk of medicinal and non-medicinal poisoning: a population-based casecontrol study in general practice. British Journal of General Practice, 62, e827-33.
2. Malone, S.M., M. McGue, and W. Iacono, Mothers’ maximum drinks ever consumed in 24 hours predicts mental health problems in adolescent offspring. Journal of Child Psychology & Psychiatry, 51, 1067-1075.
3. Jennison, K.M. (201). The impact of parental alcohol misuse and family environment on young people’s alcohol use and behavioral problems in secondary schools. Journal of Substance Use, 19, 206-212.
4. McCambridge, J., McAlaney, J., & Rowe, R. (2011). Adult consequences of late adolescent alcohol consumption: a systematic review of cohort studies. PLoS medicine, 8(2), e1000413.
5. Wolfe, E. L., Davis, T., Guydish, J., & Delucchi, K. L. (2005). Mortality risk associated with perinatal drug and alcohol use in California. Journal of Perinatology, 25(2), 93.
6. Sidebotham, P., Brandon, M., Bailey, S., Belderson, P., Dodsworth, J., Garstang, J., … & Sorensen, P. (2016). Pathways to harm, pathways to protection: A triennial analysis of serious case reviews 2011 to 2014. Department for Education.
7. Manning, V., (2011). Estimates of the number of infants (under the age of one year) living with substance misusing parents. NSPCC: London
8. Pryce, R., et al., (2017). Estimates of alcohol dependence in England based on APMS 2014, including estimates of children living in a household with an adult with alcohol dependence. Public Health England: London.
9. Kaner, E. F. S., Beyer, F. R., Muirhead, C., Campbell, F., Pienaar, E. D., Bertholet, N., Daeppen, J. B., Saunders, J. B., Burnand B (2018). Effectiveness of brief alcohol interventions in primary care populations (Review). The Cochrane Library.
10. Connor, J. P., Haber, P. S., & Hall, W. D. (2016). Alcohol use disorders. The Lancet, 387(10022), 988-998.
11. Glass, J. E., Hamilton, A. M., Powell, B. J., Perron, B. E., Brown, R. T., & Ilgen, M. A. (2015). Specialty substance use disorder services following brief alcohol intervention: a meta‐analysis of randomized controlled trials. Addiction, 110(9), 1404–1415.
12. Beck, A. K., Forbes, E., Baker, A. L., Kelly, P. J., Deane, F. P., Shakeshaft, A., … & Kelly, J. F. (2017). Systematic review of SMART Recovery: Outcomes, process variables, and implications for research. Psychology of Addictive Behaviors, 31(1), 1.
13. Glass, J. E., Hamilton, A. M., Powell, B. J., Perron, B. E., Brown, R. T., & Ilgen, M. A. (2015). Specialty substance use disorder services following brief alcohol intervention: a meta‐analysis of randomized controlled trials. Addiction, 110(9), 1404–1415.
14. Kaner, E. F. S., Beyer, F.R., Muirhead, C., Campbell, F., Pienaar, E. D., Bertholet, N., Daeppen, J, Saunders, J. B., and Burnand, B. (2018). Effectiveness of brief alcohol interventions in primary care populations. The Cochrane Library.
15. Lui, S., Terplan, M., & Smith, E. J. (2008). Psychosocial interventions for women enrolled in alcohol treatment during pregnancy. The Cochrane Library.
16. McGovern, R., Gilvarry, E., Addison, M., Alderson, H., Carr, L., Geijer-Simpson, E., … & Kaner, E. (2018). Addressing the impact of non-dependent parental substance misuse upon children.
17. Knight, J. (2015). Adult substance misuse statistics from the National Drug Treatment Monitoring System (NDTMS) 1 April 2014 to 31 March 2015. London: Public Health England.
18. Rehm, J., Anderson, P., Barry, J., Dimitrov, P., Elekes, Z., Feijão, F., … & Marmet, S. (2015). Prevalence of and potential influencing factors for alcohol dependence in Europe. European addiction research, 21(1), 6-18.