According to the United States National Institute on Drug Abuse, addiction is a brain disease that causes “functional changes to brain circuits involved in reward, stress, and self-control”. Although the first instance of substance use is typically voluntary, addiction can later take over and motivate a person to keep doing it.
As addiction takes hold, the individual will require more of the substance to achieve the same positive feelings. In time, the substance may produce no pleasant feelings at all.
Abstaining from the substance, however, will trigger symptoms of withdrawal.
Heredity and genetics can influence one’s likelihood of suffering from addiction, but these factors are only part of the equation. Your heredity determines what genes you have, but your environment can influence whether certain genetics express themselves.
Addiction, therefore, is part of a much bigger picture that encompasses heredity, environment, and simple individual choices.
Hereditary factors
Genetics, inherited from one’s parents, plays a significant role in addiction. With regard to tobacco use, genetics accounts for 75% of a person’s inclination to start smoking, 60% of their tendency to become addicted, and 54% of that individual’s ability to quit.
An individual’s genetic makeup can influence their susceptibility to other substances like alcohol, heroin, and morphine. Some things that may increase the likelihood of addiction include:
- a smaller amygdala, the part of the brain that helps regulate and define emotions;
- lack of a serotonin receptor gene, which affects one’s capability for empathy;
- fewer D2 dopamine receptors, which control the synthesis, release and uptake of the neurotransmitter that regulates mood and feelings of motivation;
- less of the PSD-95 protein, which regulates a wide variety of receptors, signals and responses in the body.
Environmental factors
Environmental factors have a major role in addiction as well, as an individual’s home environment can impact their likelihood of developing an addiction.
In a home where one or more adults suffer from addiction, children may experience:
- exposure to addictive substances;
- an attitude of acceptance towards addictive substances;
- exposure that normalises addictive behaviours;
- lack of structure;
- high degrees of stress and anxiety; and/or
- childhood traumas.
When an individual has no exposure or access to drugs, they’re far less likely to use them. Adolescents who have friends who use drugs are far more likely to use them as well.
In this instance, it’s the environment, and not heredity, that makes the individual more likely to develop an addiction.
Heredity and environment combined
A combination of genes and environmental stressors represents up to 60% of an individual’s risk of addiction. It’s often difficult to separate the two, especially when one’s parents are addicts themselves, as this contributes to both heredity and the environment.
So, is addiction hereditary? Although genes may increase one’s propensity for addiction, this does not mean they entirely prevent or conclusively cause addiction in and of themselves.
Rather, it is a complex combination of factors that determines whether an individual tries and becomes addicted to substances.
Regardless of the cause, addiction is treatable, and recovery is always possible. If you or someone you know is suffering from addiction, it’s never too late to seek help.
Dennis Relojo-Howell is the founder of Psychreg. Connect with him on Twitter @dennisr_howell.