Risk factors for depression and how to prevent it
Depression is currently a very common illness. Data collected over the years indicates that this illness has reached pandemic proportions and that by 2030 it will be the leading cause of disability worldwide.
Although, fortunately, healthcare professionals are increasingly proactive in diagnosing depression, there are still many patients who are not properly diagnosed .
Firstly, cases are diagnosed as depression that do not meet the diagnostic criteria for this disorder and that may represent situations of emotional distress or anxiety secondary to various life difficulties. We could speak of subthreshold depression, and in many of these cases, the functional impact that is the main characteristic for a diagnosis of depression is even lacking.
If the symptoms don't significantly impact the person's daily life, it's very likely that we're not dealing with a case of depression in the strict sense. Whether or not this person needs intervention to help them is something we'll discuss throughout this article.
Secondly, cases of depression that are indeed present often go undiagnosed for various reasons: symptoms are not recognized because the patient does not report them, or because the healthcare professional lacks the skills to ask about them. We could elaborate on the reasons for these situations, which are very common in primary care consultations.
We know that some people come to consultations where the feeling of being overwhelmed is significant: a lack of time perceived by both the patient and the professional, a lack of privacy to discuss sensitive topics, a lack of empathy that could facilitate dialogue, etc…
There is still a long way to go in terms of the proper recognition of depression, not to mention the correct therapeutic management.
What we do know is that depression causes significant disability for the person who suffers from it and greatly affects their environment. We will not focus here on the undeniable economic repercussions measured by the functional limitations of people with depression, including associated morbidity and mortality (from the impact on employment to the serious consequences of suicide), but it is important to emphasize that in 70 to 80% of cases, people with depression will suffer from a chronic disorder.
Combating depression, therefore, involves not only diagnosing and treating those affected appropriately, but also, and very importantly, helping those at risk of developing this disorder. It entails a commitment to reducing the incidence of new cases of depression by intervening preventively and on a personalized basis , taking into account individual risk factors.
To achieve this, we will first introduce the concepts of depression risk factors and the depression risk equation.
Risk factors for depression
Due to the high incidence, prevalence, and costs associated with depression, it is vitally important to address the problem of this disease not only through intervention in cases but also through prevention.
Depression prevention is directly aimed at reducing new cases of the illness, that is, at decreasing the incidence of depression and, consequently, the prevalence of the disease. The prioritization of strategies to be developed must be based on a comprehensive understanding of the illness and its risk factors.
The pandemic is causing a surge in cases of depression and anxiety worldwide.
The only way to understand the risk factors for a disease is through longitudinal studies that can establish a temporal relationship (causality). Unfortunately, these studies are scarce, as they require following a cohort of varying size, depending on the disease's incidence, for a sufficient period to allow the disease to develop. This makes them costly, both in terms of money and human resources. Therefore, most of the available information comes from cross-sectional studies.
In the case of depression, multiple biological, psychological, and social factors have been identified as contributing to it. This has led to the traditional argument that depression is a multifactorial illness influenced by various factors, ranging from genetic to environmental. Some of the various factors involved in depression are:
Genetic factors
There is a genetic predisposition to depression, which has been demonstrated in several genetic studies. Most notably, research has identified the 5-HTTLPR genotype as a risk factor for depression. A clear relationship has also been established between genetics (or its expression) and its potential environmental modification. That is, genetics could be altered by environmental factors, with this interaction potentially explaining the presence of depression. Therefore, genetic predisposition alone is not sufficient to diagnose depression.
Biological factors
Biological factors such as age and sex have typically been identified as risk factors for depression. Age is generally considered one of the main risk factors, with some population groups being particularly vulnerable (adolescents and the elderly). Regarding sex, depression has traditionally been diagnosed more frequently in women.
On the other hand, there are hormonal hypotheses that can explain the differences between men and women . In this regard, the protective effect of estrogens on depression and the depressive effect of progestogens have been demonstrated. Hormonal changes linked to the female menstrual cycle and menopause, as well as to treatments with contraceptives or hormone replacement therapy, have also been studied. The frequent cases of postpartum depression should also be noted. The protective effect of androgens in men has also been confirmed.
In addition to the aspects mentioned, other biological mechanisms implicated in depression include the dysregulation of the adrenergic, serotonergic, and dopaminergic systems, and the disruption of the circadian sleep-wake rhythm influenced by melatonin. In any case, it is unknown whether these neurobiological alterations are more a cause or a consequence of depression.
Finally, it is important to highlight the growing, though not yet fully understood, relationship between biological factors and depression. In this regard, depression is increasingly prevalent in patients with comorbid physical illnesses , such as osteoarthritis or even ischemic heart disease. The biological factors involved in these relationships are unknown, although it has been suggested that inflammatory or autoimmune alterations associated with chronic stressors could play an etiological role. It remains unclear whether any autoimmune factor biologically conditions the presence of depression or whether depression is a consequence of the impact of autoimmune disease. Further longitudinal studies are needed to properly establish causality in all these relationships between depression and biologically based diseases.
Psychological comorbidity and personality
Although anyone can be affected by depression, some personality types are more vulnerable. Neurotic individuals , whose fundamental traits are insecurity and feelings of inferiority, frequently experience major depression, although in many cases they also have dysthymia or subthreshold depression. Obsessive individuals , who tend to be perfectionists and excessively meticulous and orderly, are more vulnerable to major depression. Thus, we could speak of a vulnerability that generally involves low self-esteem, feelings of hopelessness, lack of self-control, and a lack of strategies for overcoming difficulties.
In addition to personality traits, other comorbid psychological problems , such as anxiety disorders, are frequently associated with depression. In this regard, it is important to note that the association between these two health problems is bidirectional; that is, patients with depression are at higher risk of developing anxiety, and patients with anxiety are at higher risk of developing depression. The relationship between these two conditions has also been studied in primary care, as patients very often present with comorbidity between them.
Patients with depression are at higher risk of developing anxiety, and patients with anxiety are at higher risk of developing depression.
Finally, it should be noted that people who exhibit addictive behaviors involving the abuse of toxic substances are affected by a psychological vulnerability to depression.
Stressful life events
Stressful life events must also be considered as a group of factors that confer a risk of affective morbidity. Thus, stressful childhood experiences such as sexual abuse, the absence of a parent, or parental suicide are considered risk factors. Other psychologically traumatic events associated with depression include grief following the loss of a loved one or chronic stress due to unemployment or overwork. Workplace bullying can also represent a risk factor for depression.
The perception of discrimination (for any reason, including racial discrimination) also implies a stressful life burden and represents a risk factor for depression. Regarding other potential stressful life events, studies are inconclusive when considering immigration, for example, as a risk factor for depression. Despite the significant impact of such a major change, the primary stressor does not appear to lie in immigration itself, but rather in the perception of secondary social isolation.
Social conditions
Certain unfavorable social conditions represent risk factors for depression. Depression is more prevalent in populations with low levels of education, low incomes, and economic hardship. Dissatisfaction with paid or unpaid work (such as housework or caring for dependent individuals) also represents a risk factor for depression.
In relation to the situation arising from cohabitation at home, the perception of dissatisfaction with the cohabitation situation also represents a risk factor.
While the perception of social isolation represents a risk factor for depression, conversely, the perception of social support represents a protective factor. This protective effect has been demonstrated even in situations with a high risk of depression due to vulnerability secondary to highly unfavorable social conditions.
Table 1. Risk factors involved in depression grouped by different etiological categories
Category of factors | Factors involved |
|---|---|
Genetic factors |
|
Biological factors |
|
Psychological comorbidity and personality |
|
Stressful life events |
|
Social conditions |
|
Personalized depression risk and depression risk equation
A study published in the United States proposed that, once the risk factors for depression are known, a specific preventive approach should be attempted . This involved implementing something similar to what is practically carried out in healthcare settings for other types of health problems, such as cardiovascular risk (SCORE), bone fractures, or, more recently, cancer. In these cases, a risk prediction algorithm is used, which is very useful for clinical decision-making. The study suggested attempting to delve deeper into each person's individual risk of experiencing a depressive episode, thereby enabling the establishment of the most appropriate preventive activities for each case.
Following this line of reasoning, the PredictD-Europe study was launched with the aim of developing a predictive algorithm for major depression. This study, which began in 2003, included 7,220 primary care patients from six European countries (Slovenia, Spain, Estonia, the Netherlands, England, and Portugal) and 2,825 patients from Chile, where the algorithm's external validity was established. The study used 39 major factors associated with depression, compiled from previous scientific literature, to construct a model. The study concluded that the risk of developing depression after one year can be determined using an equation (the PredictD-Europe equation).
Following the European study, the PredictD-Spain study was conducted, adapting the risk equation obtained in the European study to the Spanish population. Furthermore, genetic factors were included, and the characteristics of the healthcare system (professionals and services) were taken into account. The follow-up period was also extended to three years to facilitate longer-term prediction.
The PredictD-Spain study included more than 5,000 primary care patients from seven Spanish provinces. Table 2 presents the risk factors according to the European or Spanish equation.
Table 2. Risk factors used in the depression risk equation in the PredictD-Europe and PredictD-Spain studies.
PredictD - Europe | PredictD - Spain | |
|---|---|---|
Non-modifiable risk factors | Age | Age |
Sex | Sex | |
| _______________ | Age-sex interaction | |
Educational level | Educational level | |
History of depression | History of depression | |
| ________________ | Home mortgage | |
Psychological problems in a first-degree relative | Child abuse | |
| Country | Province | |
Modifiable risk factors | Dissatisfaction with paid and unpaid work | Dissatisfaction with unpaid work |
Worse physical health | Worse physical health | |
Worse mental health | Worse mental health | |
Perception of discrimination | Dissatisfaction with living together at home | |
| _______________ | Serious problems in people close to you | |
| ________________ | Taking anxiolytics or antidepressants |
Any Spanish person can currently find out their individual risk of suffering from depression, based on the equation of the PredictD-Spain study, by accessing the website http://www.predictplusprevent.com/Calculadora.php and filling in the requested data.
Having tools to determine the level and risk profile of depression can be useful for implementing personalized preventative interventions. To this end, we first provide an update on the main concepts related to prevention.
Types of prevention
According to the prevention strategy: primary, secondary, tertiary and quaternary
In relation to health, prevention refers to the measures taken to avoid the onset of a disease (primary prevention) or to prevent a negative impact of the disease on health (secondary and tertiary prevention). From a health perspective, primary prevention represents the first step in prevention and, therefore, the most desirable, since it prevents the occurrence of new cases of disease (reducing the incidence and prevalence of the disease). Secondary prevention is also important to avoid undesirable disease progression. Thus, for example, an appropriate secondary prevention measure to avoid chronic depression is the appropriate treatment with antidepressants in a patient experiencing a first episode of depression or an early diagnosis of the illness.
Tertiary prevention focuses on the rehabilitation of patients with a high degree of functional impairment. In the case of depression, its effectiveness has been demonstrated in specific patient profiles, such as the elderly.
Finally, we speak of quaternary prevention when we refer to the prevention of the consequences of overtreatment that some patients may experience, especially today, where there is a significant amount of pharmacological prescription for different comorbid chronic health problems.
According to the scope of prevention: universal, selective and indicated prevention
Universal prevention applies to the entire population regardless of their risk of developing a disease. Selective prevention applies to individuals at risk of developing the disease, while indicated prevention applies only to those who may have symptoms of the disease but do not yet meet diagnostic criteria. In the case of depression, universal prevention would involve the entire population, selective prevention would involve individuals with specific risk profiles for depression (for example, people with cardiovascular disorders or pregnant women), and indicated prevention would involve individuals at high risk or with depressive symptoms who do not meet diagnostic criteria for the disease.
Primary prevention of depression: general aspects
The scientific literature reveals several studies on the primary prevention of depression. These studies differ in terms of the population studied and the context in which they are conducted.
Prevention of depression in children and adolescents
Most studies on primary depression prevention focus on children and adolescents. In many cases, these are educational intervention programs implemented in schools or educational settings with the aim of preventing the onset of depression at an early age. Despite this evidence, published meta-analyses have questioned the long-term effectiveness of these interventions and have concluded that, currently, there is insufficient evidence to recommend widespread prevention programs for children and adolescents. In any case, it is important to bear in mind that depression at these ages increases the risk of developing depression in adulthood.
Prevention of depression in adults
In the case of primary prevention of depression in the adult population, most studies have focused on preventive interventions in specific populations traditionally considered more vulnerable to depression (selective prevention). These studies have included pregnant women, women in disadvantaged socioeconomic conditions, stroke patients, patients with subthreshold depression (indicated prevention), and institutionalized patients. Published interventions in these populations have generally demonstrated positive effects in reducing cases of depression.
Most of these have been carried out on specific populations, by mental health specialists, with specific psychotherapeutic interventions and in care settings other than primary care.
Depression prevention in primary care: a reality
Primary care represents the gateway to healthcare in much of the Western world. Its specific characteristics, such as accessibility, continuity of care, and comprehensive care for the population, provide a unique and optimal framework for health promotion and disease prevention activities. In the case of depression, the family physician's longitudinal knowledge of the population served offers an excellent opportunity to implement activities that can effectively impact the mental health of the population.
It is within this healthcare context that primary prevention activities for depression can be promoted more efficiently, which can help reduce the prevalence of the disease and prevent complications associated with it.
Primary care provides a unique and optimal framework for carrying out health promotion and disease prevention activities
Until a few years ago, however, the reviewed scientific literature had not shown evidence of any clinical trial of primary prevention of depression in the population served in primary care carried out by the professionals themselves.
The PredictD-CCRT clinical trial was conducted in primary care settings in seven Spanish cities (Barcelona, Bilbao, Granada, Jaén, Málaga, Valladolid, and Zaragoza) from 2010 to 2013. This clinical trial, involving 3,226 patients and 140 family physicians, implemented a primary prevention intervention for depression based on the risk level and profile of patients seeking primary care. The intervention was administered to a randomized selection of at-risk adult patients and was carried out by their family physicians in the intervention group, while patients in the control group received standard care. The risk profile was calculated using the depression risk equation developed in the PredictD-Spain study . The professional informed the people in the intervention group about their risk of depression and, according to the risk profile, adapted a minimal psychoeducational intervention based mainly on lifestyle elements (diet, physical exercise, sleep hygiene, social care), carried out through a motivational style interview.
The main objective of this study was to evaluate whether this psychoeducational intervention could decrease the incidence of major depression after one year.
Dr. Juan Ángel Bellón Saameño
The PredictD-CCRT intervention achieved a 31% reduction in the incidence of depression in the intervention group compared to the control group (OR 0.69 (95% CI 0.50-0.96)), after adjusting for the probability of developing depression at 12 months. A reduction of more than 30% in the incidence of a potentially chronic and debilitating illness like depression, with a number needed to treat (NNT) of 35, suggests that the PredictD-CCRT intervention opens the possibility of establishing specific psychoeducational prevention strategies for implementation in primary care. These strategies should be based on each patient's individual risk profile and an intensity appropriate to their risk level. This type of individualized preventive intervention, tailored to each person's risk profile, is currently known as personalized prevention.
The PredictD-CCRT study demonstrated not only the effectiveness of the intervention but also its efficiency and positive cost-effectiveness profile. It is important to note that this was a minimal intervention performed by family physicians on their patients in the usual clinic setting, without requiring additional resources.
An example of what this intervention could entail was informing the person that, despite any personal, family, or social problems they might be experiencing, they did not have depression and that their individual risk could be improved by engaging in preventative activities such as physical exercise or participating in enjoyable social activities. Sometimes, it was simply a matter of reinforcing activities the person was already doing, which, perhaps without them even realizing it, were helping to prevent depression.
This attitude of preventive vision of depression on the part of the primary care professional can have a great impact on the emotional health of the population served and, therefore, on the lives of their patients.
