Genes for Depression Can Shape Life Circumstances

The fundamental symptoms of depression, including alterations in energy, activity, cognition, and mood, have been documented for over 10,000 years, whereas the term “depression” itself has been in use for approximately 350 years.

Despite its extensive history, there’s no consensus among experts regarding the definition or causes of depression. However, many agree that depression isn’t a singular entity but rather a diverse range of illnesses with varied causes and mechanisms. Consequently, determining the most suitable treatment for each individual can be challenging.

Reactive depression versus endogenous depression

One approach involves identifying subtypes of depression to determine if tailored treatments might be more effective. For instance, reactive depression, linked to external stressors like trauma or loss, contrasts with endogenous depression, attributed to internal factors such as genetics or brain chemistry.

While this classification is widely accepted in mental health practice, we believe it oversimplifies the complex relationship between genetic predisposition and environmental stressors in depression onset. Research suggests that both genes and life events interact to heighten depression risk, with genetic factors influencing individual responses to the environment, including stressful situations.

What we did and what we found

Our study aimed to assess whether categorizing depression as reactive or endogenous was justified by examining the role of genes and stressors. In the Australian Genetics of Depression Study, individuals with depression completed surveys detailing their exposure to stressful life events, while we analyzed their DNA samples to determine their genetic predisposition for various mental disorders.

Our inquiry was straightforward: does genetic susceptibility to depression, bipolar disorder, schizophrenia, ADHD, anxiety, and neuroticism influence individuals’ reported exposure to stressful life events? We chose to assess genetic risk for a range of mental disorders beyond depression due to overlapping genetic variants and the diverse genetic makeup of individuals with depression.

Contrary to expectations, our analysis of over 14,000 individuals with depression revealed an unexpected finding. Those with a higher genetic risk for depression, anxiety, ADHD, or schizophrenia reported experiencing more stressors. Incidents such as assault, sexual assault, accidents, legal and financial issues, and childhood trauma were more prevalent among individuals with elevated genetic susceptibility to these mental disorders.

These associations persisted irrespective of factors like age, gender, or family dynamics. However, our study did not explore potential influences such as socioeconomic status, and we relied on participants’ recollection of past events, which may introduce inaccuracies.

What is the influence of genes?

How do genetic predispositions for mental disorders influence individuals’ responses to environmental factors?

Consider two individuals facing job loss: one with a high genetic risk for depression and another with a low risk. The genetically vulnerable person may perceive the loss as a blow to their self-esteem and social standing, leading to feelings of shame and despair.

Consequently, they may struggle to seek new employment due to fear of facing a similar outcome. Conversely, the other individual may view the job loss as less personal and more attributed to the company’s circumstances. These varying perspectives illustrate how genetic predispositions shape individuals’ interpretations and memories of events.

Furthermore, genetic risk for mental disorders can influence the likelihood of individuals encountering adverse environments. For instance, a heightened genetic risk for depression may impact self-worth, increasing the probability of engaging in dysfunctional relationships that subsequently lead to negative outcomes.

What are the implications of our study for understanding depression?

Our findings highlight the complex relationship between genes and environments, emphasizing how genes shape both our surroundings and our responses to them.

Moreover, our research challenges the clear-cut categories of reactive and endogenous depression, suggesting instead that depression arises from a blend of genetic factors, biological elements, and environmental pressures.

Furthermore, those with a stronger genetic predisposition to depression often report facing more significant stressors over their lifetimes.

Clinically, individuals with a heightened genetic vulnerability to depression might find benefit in learning targeted stress management techniques. These approaches could potentially reduce the risk of depression onset and help manage ongoing exposure to stressors for those already dealing with depression.

Read the original article on: Science Alert

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