Does Addiction Run In The Family? Genes And The Home Environment

Addiction In Families

It is widely accepted within the literature on substance abuse disorders that problems with addiction tend to run in families; individuals who grew up with parents who struggled with addiction are more likely to also have problems with addiction themselves later on in life. 1-3 This predisposition to developing an addiction disorder can be accounted for by the interaction of both environmental and genetic factors.
Addiction In Families

Studying Addiction in Families

"...shared familial beliefs about the substance and addiction will also shape the child's inclination towards substance abuse." Addiction disorders are quite heritable (i.e., passed down through genes). There are a number of ways to explore the heritability of a disorder, including familial, adoption, and twin studies. 2

In family studies, occurrence rates of a disorder within members of a family are examined. While this provides a nice estimate into how often an addiction might occur in a family, it does not account for the role of the environment. While genetic influences may be at play, factors associated with growing up in a home with an addicted parent, exposure to the addictive substance and other addictive behaviors, and shared familial beliefs about the substance and addiction will also shape the child's inclination towards substance abuse.

In an effort to better isolate and examine the factors related to the genetic transmission of addiction, studies using twins and children who have been adopted have been employed. 4 Generally, results from these studies indicate that heritability rates of addiction disorders range from 0.39 for hallucinogenic drugs to 0.72 for cocaine. 5 Findings from a study exploring families of twins indicate that early initiation of substance use, which may contribute to the development of an addiction disorder, is most strongly predicted by factors relating the family and social influences. 3 Further, first-degree relatives (i.e., a sibling, parent, or child) of someone with a history of addiction are between 4 to 8 times more likely to develop problems with addiction themselves when compared to those who do not have a family member with an addiction.


Genetics: One Contributor to Addiction

It has been found that genetics can play a role in the development of addiction. Genes may contribute to the vulnerability to substance abuse in a number of ways: genetic mutations that lead to alterations in the structure and function of the brain may influence the way in which the individual responds to exposure to the substance. 6For example, the gene aldehyde dehydrogenase 2 (ALDH2) has been known to be a protective factor of alcohol dependence by affecting the way that alcohol is broken down in the body. Moreover, individuals may be genetically more likely to exhibit problems with impulsivity, poor emotion regulation skills, executive dysfunction, or other temperamental characteristics that may increase their individual risk for using substances. 7

While certain genes have been proposed to contribute to addiction, including the interaction of multiple genes, it is uncertain whether a true genotype of addiction can ever been discovered, due to the complex personality and environmental factors that also shape addiction. 20


Psychiatric and Temperamental Factors

It has been estimated that more than half of those individuals struggling with addiction to a substance also meet criteria for additional psychiatric diagnoses, such as a mood or anxiety disorder. 8Personality disorders are also prevalent in individuals who are addicted to substances. In particular, antisocial personality disorder, which is characterized by maladaptive behavior patterns including dishonesty, manipulation, insensitivity, and breaking the law. 9, 10

While many temperamental traits may lead an individual to using drugs, symptoms of anxiety or depression many also contribute to the individual's motivation to seek out a substance. Indeed, substances offer relief from suffering. Therefore, individuals struggling with increased stress, anxiety, or feeling down and depressed may seek out drugs and alcohol as a way of coping with these negative emotions. 4, 11

Physiological differences have also been explored as potentially contributing to the development of addiction. For instance, differences in terms of an individual's sensitivity to have more intense perceptional experiences may influence whether an individual is particularly drawn to the experience of using a substance. Alternatively, these differences in the physiological response to substances may also make the experience of using an unpleasant one, therefore impeding the individual's potential to seek out the substance again. 9

Addiction in the Household: What It's Like in a Drug and Alcohol Home

 While genetics are a critical component to the development of problems associated with addiction, the environment also plays an important role in this risk. There are many ways in which growing up with a parent or parents who are addicted to substances may influence one's vulnerability to the disorder.

Families with one or more parent suffering from addiction are often difficult to live in and lead to abnormal degrees of stress. 14, 15 There are generally few normal routines in these families, making day-to-day life unpredictable. Further, parents with addiction likely exhibit intense mood swings and erratic behavior. 16 Children are often exposed to traumatic and intensely stressful experiences, and may develop patterns of anxiety or even ambivalence in response to this chronic stress and unpredictability. 17 Child abuse is also more prevalent in families of an addicted parent. 16

Some studies have suggested that children of addicted parents struggle with feeling overwhelmed by very strong emotions. 17 This is likely because the stressful experiences as a result of the addiction environment impeded their emotional development. Moreover, these children lack appropriate familial support and guidance in terms of learning how to appropriately regulate their emotional responses to situations in order to deal with them. They will often default to responding with defensiveness to intense emotion, including shutting down, withdrawing, intellectualizing, rationalizing, acting out, or self-medicating. 18

It is not uncommon for families of an addict to become constricted in terms of emotional responses. 15 Family members believe that they are not able to show their true authentic selves, as they fear this may trigger disaster and chaos. Therefore, these individuals may withdraw and make excessive efforts to appear calm and collected. Children of these types of families will enter adulthood struggling with emotional and psychological baggage that can impact their functioning at work, school, or in their relationships with others. 16, 19


Adults of Parents Who Were Addicted

In many instances, problems related to growing up in the home of an addicted parent do not manifest themselves until well into adulthood. 13 Adult children of addicts are often characterized by the following traits:

  • Depression or anxiety: Adult children of addicts are more likely to suffer from symptoms of anxiety and depression, likely because they failed to learn effective methods for managing their emotional responses during childhood.
  • Constriction of emotions: Adult children of addicts have a tendency to shut down or block out their emotional responses to situations, as a way of dealing with feelings of overwhelming pain. They exhibit a restricted range of affect and lack abilities in the authentic expression of emotions.
  • Distortions with reasoning abilities: Adult children of addicts often make convoluted attempts to explain, understand, and make meaning of difficulties that seem senseless to others.
  • Lack of trust: Individuals of addicted parents often do not know how to trust others, given their history of disrupted and insecure attachment to an addicted caregiver.
  • Hypervigilance: Adult children of addicts often worry excessively about potential danger or catastrophe.
  • Lack of abilities in self regulation: Adult children of addicts often exhibit dysregulated affect and emotion, owing to impairments within the limbic system and prefrontal cortex.
  • Tendency toward addiction: Adult children are more likely to choose to self-medicate with substances, therefore predisposing them to developing problems with addiction.

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