Addictions and their familiality in Iceland.
Here, we provide an overview of previous family studies of addiction and present a new family study based on clinical data for more than 19,000 individuals who have been treated for addiction in Iceland over the last three decades. Coupled with the extensive Icelandic genealogy information, this population-based sample provides a unique opportunity for family studies. The relative risk (RR) was determined for up to fifth-degree relatives of probands diagnosed with alcohol, cannabis, sedative, and amphetamine dependence. We observe highly significant RR values for all substances ranging from 2.27 for alcohol to 7.3 for amphetamine, for first-degree relatives, and RRs significantly above 1 for distant relations, where the effect of shared environmental factors is minimized. The magnitude of risk in psychostimulant dependence is particularly striking. These findings emphasize the role of genetics in the etiology of addiction and highlight the importance of substance-specific effects.
Tyrfingsson
Thorarinn
T
SAA Treatment Center, Reykjavik, Iceland.
Thorgeirsson
Thorgeir E
TE
Geller
Frank
F
Runarsdóttir
Valgerdur
V
Hansdóttir
Ingunn
I
Bjornsdottir
Gyda
G
Wiste
Anna K
AK
Jonsdottir
Gudrun A
GA
Stefansson
Hreinn
H
Gulcher
Jeffrey R
JR
Oskarsson
Hogni
H
Gudbjartsson
Daniel
D
Stefansson
Kari
K
D000437:Alcoholism / Q000235:genetics; D019969:Amphetamine-Related Disorders / Q000235:genetics; D019970:Cocaine-Related Disorders / Q000235:genetics; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005789:Genealogy and Heraldry; D006801:Humans; D006993:Hypnotics and Sedatives; D007055:Iceland / Q000453:epidemiology; D008297:Male; D002189:Marijuana Abuse / Q000235:genetics; D008393:Marriage; D009293:Opioid-Related Disorders / Q000235:genetics; D010287:Parent-Child Relations; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000235:genetics* / Q000628:therapy
D006993:Hypnotics and Sedatives