Although the exact causes of depression have not yet been identified, certain risk factors can lead to the development of this mood disorder. Understanding why this mental illness occurs can help in more accurate diagnosis and effective treatment.
Causes And Risk Factors Of Depression
Major depressive disorder (MDD), also known as clinical depression or simply as depression, is a mental condition that leads to a chronic state of sadness, irritability, low mood, inactivity and, in extreme cases, suicidality. Most of us are well aware of some of the most common risk factors that may trigger this psychiatric disorder, such as loss of loved one, trauma, breakup or unemployment. However, there are many other factors that may work in tandem resulting in the onset. Hence, it may often be challenging to identify the exact cause.
As a combination of different risk factors can trigger MDD, the symptoms, severity can vary from person to person. While someone can feel depressed due to some negative life experiences, another person may be depressed without any specific reason, mostly triggered by brian chemicals or genetics. Moreover, a person’s mindset, thought process, personality, empathic abilities, family environment and coping skills can also act as contributing factors. Hence, various risk factors play a significant role in the development of this mental condition.
Here are some of the most prominent and research-backed risk factors and causes of depression:
According to Harvard Medical School, several genes affect our mood and play a crucial role in mood disorders. Researchers 1 have found that depression tends to run in families. If a first degree or close relative, like a parent or a sibling, has suffered from any depressive disorders (DDs) in the past, then it is highly likely that you may also develop MDD. One 2000 study 2 explains “Major depression is a familial disorder, and its familiality mostly or entirely results from genetic influences.” However, no particular gene has been identified yet. As it is a complex condition, the risk of the disorder is influenced by different genes which have small effect sizes 3 instead of any particular gene. It should also be noted that having a genetic predisposition doesn’t necessarily mean that someone will be diagnosed with the disorder as personal factors and life experiences also play a vital role.
Research 4 shows that family and twin studies have revealed significant evidence that genetic factors play a contributing role in the development of major depressive disorder. The researchers found that the heritability rate for this mood disorder is about 37%. It was also observed that there is a threefold increase in the risk of development “in first-degree offspring of patients” with the disorder. The research adds “Heritability has also been shown to be especially influential in severe forms of depression. The illness severity depends on whether DDs are inherited maternally or paternally.” One 2010 study 5 suggests that the heritability for MDD is about 40-50% and hence, has a substantial influence on risk of MDD onset. The disorder is also believed to have “complex genetic heterogeneity,” which means different partly overlapping susceptibility genes can make someone vulnerable to such a depressive disorder when interacting with environmental factors. The study also found that the Serotonin Transporter (5HTT/SLC6A4) gene and other “genes involved in the serotonergic system are candidate genes for susceptibility to depression given that many antidepressant medications act on these systems.”
Researchers 6 also believe that recognizing gene and environment interactions (GxE) are also highly important as both factors play an unprecedented role in the etiology of MDD. According to a 2015 study 7 , genes (nature) and environments (nurture) studies help to understand how genetic variants affect the association between this mood disorder and environmental factors. “A deeper understanding of the etiology of depression, including both its genetic and environmental determinants, as well as their interplay (e.g. gene-environment interaction; GxE 8 ) will have implications for preventing depression and informing its clinical treatment,” adds the study. Genetic analysis 9 and identification of risk variants can help us understand how MDD develops and can pave the way to develop better treatment approaches and prevention strategies.
2. Brain Chemistry
Depressed people tend to have certain differences in the brain structure 10 and chemistry compared to people without MDD. A 2007 study 11 states “Major depressive disorder is an illness with significant neurobiological consequences involving structural, functional and molecular alterations in several areas of the brain.” Studies 12 show that patients with major depressive disorder (MDD) have “bilateral and unilateral reductions in hippocampal volume relative to healthy controls.” The hippocampus of the limbic system is a complex structure in our brain’s temporal lobe. It plays a vital role in learning, memory & recollection. This part of the brain tends to be smaller 13 in people with depression and involves limited serotonin receptors 14 . One 2005 study 15 suggests that “diminished activity of serotonin pathways plays a causal role in the pathophysiology of depression.” Serotonin is an important neurotransmitter which stabilizes mood and happiness. Research 16 shows that the age of onset, frequency of depressive episodes, number of recurrent episodes, & length and duration of lifetime MDD are associated with smaller hippocampal volumes.
Although it is not exactly clear why the hippocampus appears to be smaller in depressed individuals, cortisol, which is the primary stress hormone, is released excessively in sufferers. Experts believe that cortisol may play a role in the apparent shrinkage of the hippocampus. This happens because stress tends to prevent the production of new nerve cells in our hippocampus. Studies 17 have found that “stress changes neuronal morphology, suppresses neuronal proliferation, and reduces hippocampal volume.” It is also believed that some individuals are born with a smaller sized hippocampus which makes them prone to depressive disorders. However, even though the “highly plastic, stress-sensitive hippocampal region” may be a significant contributing factor in the onset of depressive illness, it is not “solely responsible” for different depressive symptoms, states a 2004 study 18 . Apart from the hippocampus, various other regions and pathways in the brain may also be associated with the development of the condition as no specific brain region is responsible for MDD. These brain regions may include:
- The medial prefrontal cortex (MPFC)
- The medial and caudolateral orbital cortex
- The ventromedial parts of the basal ganglia
- The frontal lobe
- The striatum
- The parietal lobe 19
- The amygdala
- The thalamus
Researchers 20 have observed that chronic depression is associated with increased amygdala volume and decreased volume of the frontal cortex, along with reductions in specific frontal cortex subregions, such as the orbitofrontal cortex. According to a 2008 study 21 , dysfunction in brain structures and circuits “may induce disturbances in emotional behavior and other cognitive aspects of depressive syndromes in humans.” Research 22 also shows that gray and white matter may also play a crucial role in the onset of major depressive disorder. A 2015 study 23 revealed that individuals with major depressive disorder tend to have substantial gray-matter volume (GMV) “increase in the left posterior cingulate gyrus and GMV decrease in the left lingual gyrus.”
One 2017 study 24 focused on brain structural and functional changes in adolescent individuals with severe depressive disorders and found that adolescent patients had “elevated amygdala activity to negative and reduced amygdala activity to positive emotional stimuli.” Adolescents with MDD also had smaller hippocampal volumes when compared to other healthy individuals in the same age. The study found that smaller hippocampal volumes were related to higher degrees of childhood maltreatment, but no such association was observed for amygdala reactivity. “Our results suggest that hippocampal alterations in youth MDD patients may at least partly be traced back to higher occurrence of early-life adverse experiences,” adds the study. Moreover, cortical thinning 25 in distinct and overlapping brain regions were also observed in children and adolescents with depressive disorders.
3. Environmental factors
Apart from genetic and biological factors, environmental factors also play a vital role in the development of depression. In the realm of psychiatric disorders, the term “environment” is used broadly. Experts consider it to involve everything that is not an inherited gene. It may include certain events that can trigger psychosocial stress such as abuse, breakup, grief and other adverse life events. It may also involve environmental threats like pollutants and infectious agents. Hence, it is believed that the environment can also make someone vulnerable to major depressive disorder. Reports 26 suggest that chronic stressful and adverse life events can trigger depressive symptoms. Although not everyone encountering such adverse life experiences may suffer from MDD, some people may develop depressive symptoms, especially those with a genetic predisposition.
Studies have even found environmental factors can also lead to alterations in brain structure. One 2016 study 27 states that “findings indicate that some environmental factors may lead to depression vulnerability through alterations of the neural oscillatory activity of the cerebellum during resting-state.” Some of the most common environmental factors contributing towards the development of this mood disorder may include the following:
A. Family environment
Family environmental factors, such as control, conflict or cohesion, also have a contributing role. Researchers from a 2005 study 28 state “a broad array of parent and family factors is associated with youth risk for depression, ranging from parental pathology to parental cognitive style to family emotional climate.” One 2015 study found that the family environment is a significant source of risk factors for depression. The family’s emotional climate can also contribute to child depression. “Family relationship variables of high discord, low cohesion, and high affectionless control were all important predictors of general child pathology, including depression,” explains a 2005 study 29 .
B. Adverse Childhood Experiences (ACEs)
Early life stress (ELS 30 ), such as physical abuse, sexual abuse, emotional abuse & physical or emotional neglect, are one of the strongest predictors of depression in adults. Research shows that depressive disorders are associated with childhood adversity. “Experiencing any form of childhood maltreatment was linked with increased odds of recurrent and chronic depression,” states a 2017 study 31 . Another 2009 study 32 shows that individuals having a history of childhood adversity, such as traumatic experiences in childhood, also have a higher risk of developing a chronic form of MDD. Reports 33 indicate that around 75.6% of patients with chronic MDD reported experiencing clinically significant childhood trauma, while about 37% of depressed patients claimed to have suffered multiple childhood traumatization.
Research 34 also shows that childhood sexual abuse is one of the most common early stressors leading to adult-onset depression. One 2017 study 35 revealed that experiencing emotional abuse, neglect and attachment anxiety was correlated with the development of depressive disorders. The researchers also observed that “recollections of emotional traumas” can trigger this mental condition more than adult attachment bonds. In fact, recent research 36 shows that childhood maltreatment is closely associated with suicidal behavior and increases the risk of suicide attempts in patients with major depressive disorder (MDD).
4. Personal factors
Certain factors associated with a person’s self-image, identity and personal life can also influence the onset of this mental illness. Some of these factors are:
The personality 37 of an individual may also be considered as a significant risk factor for the development of depressive disorders. Individuals with melancholic, obsessive 38 , neurotic or other such types of personalities are more susceptible to depressive episodes. “Personal vulnerabilities associated with depression include cognitive, interpersonal, and personality factors,” explains a research paper 39 . These personal vulnerabilities can lead to the onset of depression after interacting with biological and genetic factors. One 2006 study 40 found that neuroticism was observed to be specifically associated with and triggered depressive symptoms consistently in late life. Further research 41 shows that major depressive disorder is related to personality characteristics like conscientiousness, positive emotionality, extraversion or introversion, negative emotionality and neuroticism. Personality traits tend to cause the onset of this psychiatric disorder through different pathways.
One 2014 study 42 found that depressed patients have lower scores in cooperativeness, self-directedness and persistence. Another 2015 study 43 revealed that although personality traits are related to depressive symptoms, depressive disorders can, in turn, lead to personality changes, which can be either temporary or long term. Researchers suggest 44 that personality features must be considered for the better understanding & management of MDD.
B. Cognitive distortions
A person’s mindset, thinking style 45 and pattern can also lead to the development of depressive symptoms over time. Individuals who are pessimistic, prone to negative thinking, rumination, unable to let go of mistakes or difficult experiences, tendency to jump to negative conclusions and other errors in thinking are more prone to depression. Studies 46 have found that cognitive distortions 47 and negative biases in thinking can make someone susceptible to depressive disorders. According to a 2012 study 48 , negative cognitive biases, along with attention and memory biases and reduced clarity about a positive past and future, can help in the onset and maintenance of this mental illness. “Individual differences in information processing style can profoundly impact mood or even result in disorders such as depression,” adds the study.
It has been observed that rumination 49 and repetitive thinking riddled with negatively charged content, self-beliefs and emotions can lead to negative moods. When such thought patterns become chronic and are followed over a period of time, it can increase levels of stress, anxiety and depression. “Unconstructive forms of repetitive thinking 50 may represent a cognitive vulnerability factor implicated in the development and maintenance of various emotional disorders such as anxiety disorders and depression,” states a 2009 study 51 .
Read More About Cognitive Biases Here.
C. Learned helplessness
When we are conditioned to believe and think in a certain way due to stressful or adverse situations and experiences, it can often make us prone to negative thinking and pessimism, leading to major depressive disorder symptoms in the long run. Research 52 has found that this can lead to symptoms of cognitive exhaustion. As learned helplessness 53 makes us falsely believe that there is no solution to our problems, even though there are available opportunities, we tend to become passive and prevent ourselves from putting any effort to improve our life. Such thought and behavior patterns can often make us feel helpless and hopeless. As it is a conditioned thought pattern, we are unable to control our mood and emotions. A study 54 on learned helplessness found that depressed women tend to believe success depends on luck while failure depends on a lack of ability, while women who are not depressed believe success depends on high ability and attribute failure to bad luck. The study also found that “depressed women saw themselves as personally helpless when compared with others for failure outcomes; nondepressed women saw themselves as universally helpless (i.e., everyone would fail the task).”
Read More About Learned Helplessness Here
D. Relationship difficulties
Unhealthy, toxic and abusive relationships can trigger certain psychological conditions like MDD. Studies 55 have found that marital conflict is a crucial risk factor for mental illness among midlife & older adults as it can cause functional impairment through depression. Relationships with codependent or unhealthy attachment patterns, dominated by domestic violence or abuse, can increase and intensify stress, anxiety and depressive symptoms in certain individuals, especially those who are unable to cope with it. Chronic relationship issues can trigger past trauma, early life stress and make someone highly prone to feeling depressed & drained. Repeated relationship abuse, along with control, intimidation and manipulation, by a partner can severely affect someone’s mental health. According to a recent 2020 study 56 , abuse from intimate partners is strongly related to depression in females and anxiety in males.
Apart from abuse, infidelity can also play a vital role in triggering a wide range of individual consequences, such as the development of MDD and suicidality in either or both partners, according to research. This was validated by another 2016 study 57 which established the association between discovering a partner’s affair and experiencing a major depressive episode.
E. Relationship dissolution
The end of a relationship, such as a break, separation or divorce can seriously affect someone’s mental health 58 and life satisfaction. Apart from causing severe emotional turmoil, it can also bring about other unforeseen changes in life, such as moving to a new place or financial changes. In fact research 59 reveals that “The experience of separation or divorce confers risk for poor health outcomes, including a 23% higher mortality rate.” Although one may seem to be able to move on, relationship dissolution can often lead to depressive symptoms and leave one heartbroken. It has been observed 60 that marriage can lead to the onset of internalizing symptoms and marital discord can cause both anxiety and depression. One 2013 study 61 found that there is a possible significant association between major depressive disorder and separation/divorce.
Another 2019 study 62 on romantic relationship breakup and depressive symptoms found that feelings of rejection, betrayal and unexpectedness of the breakup can lead to feelings of grief and “sudden loss.” Moreover, the person may also feel a lack of positive affect 63 or emotions leading to the onset of MDD. “As expected, heartbroken females reported higher depression scores than heartbroken males in our study,” states the study. In fact further studies 64 point out that attachment-related anxiety and post-breakup depressive symptoms can lead to suicidal ideas and behavior in adults. In fact, parental separation or divorce can even adversely affect the mental health of their children, reveal researchers 65 .
F. Financial stress
Financial problems 66 can often be a crucial factor in the development of depressive disorders. As someone’s financial condition worsens over time, so can their mental health. Anxiety and depression can grow slowly and can become severe with growing debt 67 , bills, lack of finances and unemployment. It can also lead to feelings of guilt, shame and unworthiness as well as suicidal thoughts. According to a 2016 study 68 , “greater financial difficulties predicted greater depression and stress cross-sectionally.” It can also lead to increased anxiety and alcohol dependence over time. Financial strain and economic hardship can alter our emotional, cognitive & behavioral responses as we successfully meet our financial responsibilities. As financial stress is not solely dependent on income, researchers 69 found major depressive disorder (MDD) symptoms to be “strongly associated with financial adversity or strain.”
5. Substance use and alcoholism
Mental illness and substance abuse are directly related to each other. While addiction to substances can cause different mental health conditions like major depressive disorder (MDD), such conditions can also influence a person to use substances as a self-medication or coping strategy. In fact, increasing use 70 of substances or alcohol tend to increase the risk of depression. “Alcohol use disorder (AUD) and depressive disorders are among the most prevalent psychiatric disorders and co-occur more often than expected by chance,” explains one 2019 study 71 . Substance abuse along with depression is typically considered as a comorbidity or a co-occurring disorder 72 or a dual diagnosis. Substance abuse and depression feed off from one another and worsen the symptoms. Drugs 73 and alcohol 74 lead to feelings of hopelessness, emptiness, sadness, lethargy and can even increase the frequency of depressive episodes.
According to a 2018 study 75 , significant associations were found between MDD and alcohol use, cannabis use and tobacco use. “The majority of depression, anxiety and substance use cases, oftentimes, emerge during young adulthood,” adds the study. Further research 76 indicates that adolescent depression is related to alcohol and drug abuse. However, depressive episodes can also influence substance use in adolescents. “Depressive symptoms early in life may signal a risk for increasing involvement in substance use among severe emotional disturbed youth,” found a 2008 study 77 . Evidence shows that group cognitive behavioral therapy (CBT) for depressive disorder and substance use can be effective in treating these co-occurring disorders.
Read More About Alcoholism Here.
6. Diseases and medications
Another 2013 study 78 revealed that people suffering from chronic diseases, like cancer or diabetes, are more prone to develop major depression as the severity of the disease increases. The study also found that certain therapeutic drugs and medications used in treatment of physical diseases can also lead to this mental disorder. “Certain drugs may contribute to the etiology of depressive symptoms and depressive disorders,” explains a 1997 study 79 .
7. Bereavement and grief
Complicated grief 80 or prolonged grief disorder 81 , a longer-lasting and severe form of grief, is believed to be associated with grief-related major depression, which can be triggered by the loss of a loved one. Not only can it lead to MDD symptoms, it can also worsen the symptoms if someone already has the mood disorder. When a person has difficulties accepting the loss of a loved one, they can feel emptiness, hopelessness and guilt. They can also have trouble experiencing positive emotions. Research 82 has found that depressive disorders are related to symptoms of “complicated” grief. This connection is widely observed in bereaved spouses and widowed individuals who experience such “intense and prolonged emotional responses that they may be diagnosed with major depression or complicated grief (CG) disorders,” explains a 2011 study 83 . As a group of psychiatric outpatients with chronic major depressive disorder were found to have high degrees of complicated grief, such patients must be regularly screened for grief, suggest researchers 84 .
8. Social isolation and loneliness
Loneliness is influenced by environmental stresses, thought patterns and emotional states. Prolonged or chronic loneliness 85 can lead to dissatisfaction with life and cause depressive symptoms. However, loneliness is not the same as being alone. Loneliness and isolation is characterized by certain factors like, a lack of friends or an intimate partner, not feeling a sense of belonging or familiarity, not having a trusted person to share thoughts and feelings with, not being physically close with someone etc. According to a 2014 study 86 , loneliness is “a painful universal phenomenon” which shares certain symptoms with MDD such as emotional pain and helplessness. “Lonely people suffer from more depressive symptoms, as they have then been reported to be less happy, less satisfied and more pessimistic,” adds the study. It also found that there is positive relation between loneliness and suicide ideation. Another 2017 study 87 reveals that social isolation and loneliness share “a significant and unique association” with depressive symptoms as evident from multiple studies. Recent research 88 shows that young individuals are more prone to experience MDD due to loneliness, It states “Young people have a higher prevalence of loneliness than other age groups, and they are also at risk of depression.” The same effect is also evident in elderly people 89 .
9. Physical factors
A number of different physical factors can also influence the development of MDD in an individual. Some of these factors are mentioned below:
Hormonal imbalances can often cause different forms of depressive disorders. “Excessive or reduced hormonal activity during development or in adulthood may be associated with particular clusters of psychiatric symptoms,” explains a 2010 study 90 . Hormones are primarily chemical messengers which can affect our well-being and mental health. When our hormone levels are disbalanced, it can negatively affect our mood, cognition 91 , mindset and energy levels. Among the different types of hormones in our body, it is believed that thyroid, testosterone, estrogen 92 and progesterone 93 can be associated with depression. Thyroid and estrogen dysfunction can affect the release of important neurotransmitters like serotonin, dopamine and GABA, which regulate our mood. Low levels of testosterone can cause cognitive impairment, fatigue, lack of motivation and focus. Low progesterone levels can result in anxiety, brain fog, irritability and sleep disturbances.
According to a 2008 study 94 , women tend to experience depressive episodes related to reproductive events, such as premenstrual 95 , postpartum 96 and/or menopausal transition, due to increased sensitivity towards severe hormonal fluctuations. The study adds “fluctuations in sex hormones marking female reproductive events could influence neurochemical pathways linked to depression.” Moreover, childbirth 97 can also make women vulnerable to depressive disorder during pregnancy or after delivery. Another 2014 study 98 revealed that lower levels of testosterone is associated with dementia, poor cognitive performance, poorer mental health and “presence of depressive symptoms” in middle-aged and older men.
Increasing number of researchers 99 are now observing that depression and inflammatory processes are related. It has been observed that inflammatory pathways 100 and neurocircuits in our brain cause certain behavioural responses, such as alertness, alarm and avoidance, that may have served as an evolutionary advantage for early humans as they encountered predators and pathogens. But researchers believe that this connection between our brain and inflammation can lead to the development of depressive symptoms. According to a recent 2020 study 101 , “Depression is confirmed as a pro-inflammatory state.” Depressive symptoms tend to cause inflammation, while inflammatory reactions cause the development or worsens depressive symptoms. Studies 102 have found “elevated peripheral and central inflammatory cytokines and acute phase proteins in depression.”
Evidence 103 shows that inflammation plays a crucial contributing role in the etiology of depressive disorders. Research 104 consistently shows that people suffering from major depressive disorder (MDD) tend to have higher levels of different peripheral inflammatory biomarkers. One 2019 study 105 found that “increased inflammatory activation of the immune system,” which influences the periphery and the central nervous system (CNS), contribute to the onset of fatigue and MDD. It also found that this immuno-psychiatric link is also observed in depression treatment as antidepressants can help to reduce inflammation. In fact, anti-inflammatory intervention can possibly help in developing a better, more customized treatment for depressed patients.
C. Chronic illness
“Individuals presenting chronic conditions are more likely to experience depressive symptoms,” states one 2018 study 106 . Individuals struggling with chronic, long-term and fatal medical diseases 107 , such as cancer, cardiovascular disease or stroke, are more likely to develop depression. Moreover, serious head injuries can also cause emotional regulation issues and mood swings. One 2006 study 108 indicates that depressive disorders can occur with other psychiatric & physical conditions. The study adds “Physical illness increases the risk of developing severe depressive illness.” Physical illness can result in chronic psychological or cognitive impairment making the individual vulnerable to depressive episodes. Moreover, certain physical disorders can be directly linked to depression.
However, other researchers have observed that there is a bidirectional relationship between chronic medical disorders and depressive disorders. “The adverse health risk behaviors and psychobiological changes associated with depression increase the risk for chronic medical disorders, and biological changes and complications associated with chronic medical disorders may precipitate depressive episodes,” explain the researchers 109 .
Excessive and chronic smartphone 110 , internet and social media use may also play a part in the causation of depression. One 2018 study 111 found a positive correlation between depressive disorders and smartphone addiction among school educated adult and younger age users. “Numerous psychiatric problems related to excessive smartphone use have been identified, including depressive symptoms, anxiety, and low self-esteem,” explains a 2019 study 112 . Research 113 also shows that “excessive use of smartphone paired with negative attitude” can not only cause anxiety and MDD, it may also lead to suicidal behavior. Moreover, internet addiction can also adversely influence mental health and academic performance of children, adolescents and young adults as there is a significant association between the two, according to research 114 .
One 2019 study 115 found that among urban adolescents, about 71.4% of them used the Internet for social networking which increases their risk of developing stress, anxiety and depressive symptoms. Researchers from a 2016 study 116 revealed that social media use 117 , including platforms like Facebook, Instagram, Snapchat, Reddit and others, is closely associated with increased degree of depressive symptoms among young adults in the U.S. According to one 2017 study 118 , increasing screen time and time spent on social media may also increase the risk of suicide among adolescents. However, another 2016 study 119 has also observed that the usage of social networking sites (SNSs) is associated with both psychological disorders and mental well-being. But whether social media use will result in detrimental or beneficial effects will depend “at least partly on the quality of social factors in the SNS environment,” states the study.
According to research 120 , unhealthy lifestyle is strongly related to anxiety and depressive disorder in both men and women. Studies 121 have found that following unhealthy lifestyle patterns, such as a sedentary life, poor diet, smoking and heavy drinking regularly can lead to or worsen symptoms of depression. Here are some lifestyle factors to consider:
A. Poor diet
It has been observed that eating unhealthy foods 122 may lead to depressive symptoms while being in a depressed state can influence us to eat more junk food. It is also believed having a healthy and nutritious diet is associated with better mental health. Diets 123 high in sugar, fat, processed meat, high-fat dairy products, fried foods and refined food items, can adversely affect our mental health. However, a diet rich in fish protein, vegetables, fruits, fibre and other nutrients can help in coping with depression.
According to a recent 2020 study 124 , “different diets have been associated with increased or decreased risk of depression.” It was found that vegans show about 28.4% prevalence of depressive symptoms, while for omnivores prevalence is around 16.2%. Moreover, the risk for developing MDD tends to increase with the number of foods excluded from your diet. It was observed that women who consume fish at least twice a week tend to have 25% lower risk of major depressive disorder compared to women who eat fish less than twice a week. Moreover, certain foods can regulate inflammation in your body and influence MDD symptoms. “High adherence to dietary recommendations, anti-inflammatory diet, fish consumption, exclusion of processed foods, and adequate intake of folic acid, magnesium different fatty acids, were associated with a reduced risk of mental illness,” adds the study.
B. Sleep deprivation
Interestingly, sleep difficulties 125 are both a symptom and a risk factor for this mental illness. Sleep deprivation and other sleep disorders like insomnia can also influence this mood disorder. On the other hand, depressive disorders can also influence sleeping patterns 126 in the sufferer. “The majority of individuals with depression experience sleep disturbances. Depression is also over-represented among populations with a variety of sleep disorders,” explains a 2008 study . According to research 127 , subjective sleep impairments are a characteristic trait present in most depressive disorders. Moreover, sleep regulation is closely associated with the same processes involved in the pathophysiology of MDD. “Many longitudinal studies have identified insomnia as an independent risk factor for the development of emerging or recurrent depression among young, middle‐aged and older adults,” adds a 2019 study 128 .
C. Lack of exercise
Being idle and a lack of physical exercise, such as sitting for extended periods, can increase the risk of depressive disorders. According to a 2013 study, sitting time is directly associated with mental health. It found that the longer we sit, the more we will experience depressive symptoms. Research 129 shows that having sedentary lifestyle and behaviors leads to adverse mental health and sitting for long periods 130 is closely related to higher risk of MDD. It was also found that less sitting time and regular exercise can improve physical and mental health. A 2004 study 131 explains “Exercise is a behavioral intervention that has shown great promise in alleviating symptoms of depression.” Further studies 132 have found that physical exercise, such as weightlifting, aerobic exercises, running, swimming, martial arts and even brisk walking, can be “a viable tool” in effective treatment of depressed individuals. “Exercise appears to be an effective treatment for depression, improving depressive symptoms to a comparable extent as pharmacotherapy and psychotherapy,” states a 2012 study 133 .
Apart from the factors mentioned above, there may be some other factors that can contribute to the development of MDD in someone over a period of time:
- Prolonged unemployment
- Emotional neglect
- Long-term work stress
- Lack of hobbies and recreational activities
- Other recent life stresses
Understanding The Causes And Effects
By gaining a clear understanding of the different causes of depressive disorders and how they can affect our mindset, emotions, behaviors and mood, we will be better able to seek help and feel more encouraged to consult a mental health professional. Understanding the causes can enable the doctors to conduct accurate diagnosis and devise a more customized and effective treatment plan for a faster recovery.
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