Study shows that alcohol, hard drugs, and cannabis use all substantially raise the risk of death in people with schizophrenia
Copenhagen, Denmark - A study including more than 50 years of data from national registries in Denmark shows that alcohol, hard drug, and cannabis use all substantially raise the risk of death of people with schizophrenia, accounting for between a third and a half of the excess mortality in this population—clearly highlighting the need for increased intervention in this area. The research is being presented at this year’s International Early Psychosis Conference in Tokyo, Japan, and is by Dr Carsten Hjorthøj and Professor Merete Nordentoft, Mental Health Centre, Institute of Clinical Medicine, University of Copenhagen, Denmark, and colleagues.
People with schizophrenia have higher rates (between 5 and 10 times higher) of misuse of alcohol, cannabis, and other illicit substances (hard drugs) compared with the general population. They are also at severely increased risk of early death compared to the general population, with various studies estimating this increased risk at 10-15 times. The association between substance use and mortality in schizophrenia, however, is not well-established.
In this new study, the authors linked nationwide Danish registers for people born in Denmark from 1955 onwards. Hazard ratios (HR) for both all-cause and cause-specific mortality attributable to different substance use disorders were estimated. There were 41,470 incident cases of schizophrenia in the sample, and 4,616 deaths. For all-cause mortality in people with schizophrenia, all types of substance use disorders increased risk of dying, by 78% for exclusive misuse of hard drugs, by 52% for exclusive misuse of alcohol, and by 24% for exclusive misuse of cannabis. Combinations of two/three types of misuse increased the HR further—the increased risk of death for alcohol and cannabis combined was 64%; alcohol and hard drugs 165%; hard drugs and cannabis 107%; and all three combined 120%. The authors say: “The relationship was not completely linear, with underdiagnosis of substance abuse a possible explanation for this.”
The authors estimate that overall, alcohol and substance use disorders account for between a third and half of the excess mortality in schizophrenia, and believe this and their findings across the above substance abuse categories are applicable across other Western (high-income) nations.
Risk of death from accidents or respiratory-organs illness was increased for all types of substance misuse. Alcohol was associated with doubling of the risk of dying from cardiovascular causes, and increased the risk of death from diseases associated with the digestive system by 7 times (including liver disease). Misuse of all three substance categories increased the risk of death from diseases of the respiratory system by 40-70%, including lung cancer, COPD and pneumonia.
http://www.exchangemagazine.com/morningpost/2014/week46/Tuesday/14111813.htm