Depression is a frequent mood disorder. This article describes its causes, symptoms, diagnosis, and treatment.
Major depression or unipolar depression is a frequent mood disorder that involves a persistent feeling of sadness and/ or a lack of interest in external stimuli. According to the Journal of the American Medical Association, 26% and 12% of women and men in the United States, correspondingly, will have depression at some point in their lives.
Those numbers represent a significant percentage of the population. Picture it this way, heart disease (the most frequent cause of death in the United States) affects 24% of the people in the United States.
Global statistics mirror those in the United States. Over the next 20 years, depression will be the leading cause of disability in first world countries.
Unipolar depression is a significant mental health issue. It contributes to suicide incidence, causes disruption in interpersonal relationships, increases the incidence of substance abuse, and leads to lost work time.
The good news is that, unlike other mental illnesses like bipolar illness, major depression is well understood in the medical community and is often easily treatable.
Unfortunately, many depressed individuals never seek treatment for their condition. When left untreated, depression can have fatal consequences. Ignorance about depression causes the public and even some health providers to label depressed individuals as weak persons that lack personal will. This leads to painful stigmatization of the disease and more suffering.
I am a medical doctor. In this article, I will help you navigate depression, its causes, symptoms, different types, diagnosis, and treatment. Keep reading to learn everything there is to know about depression directly from the hand of an M.D.
What is an affective disorder?
Affective disorders or mood disorders are a group of psychiatric disorders that produce abnormalities in the emotional state. A person with a mood disorder tends to experience the extremes of mood.
Take sadness; for example, it is a common and perfectly normal mood, everyone feels sad from time to time, and there is nothing wrong with that. Depression, on the other hand, is sadness taken to the extreme, a persistent depressed mood is not normal, and requires medical assistance.
Mania is the other end of extreme moods. It is a state of absolute elation and activation with enhanced affective expression. Also, this condition represents a severe change in the way a person normally behaves. It can cause serious disturbances in personal relationships, work, and school.
Some manic episodes even have psychotic symptoms (i.e., hallucinations and break from reality). Hypomania is, simply put, a milder form of mania. Bipolar disorder sufferers are continually switching between both mood extremes.
Here is a list of the most common affective disorders:
- Unipolar depression (major depression)
- Bipolar disorder
- Postpartum depression
- Panic disorder
- Obsessive-compulsive disorder (OCD)
- Post-traumatic stress disorder (PTSD)
- Cyclothymic disorder
- Generalized anxiety disorder
How does unipolar depression differ from bipolar depression?
Major depression is also called unipolar disorder to connote a difference between major depressive disorder and bipolar disorder.
The term bipolar depression refers to an oscillating state between depression and mania. Unipolar depression, on the other hand, only has depressive symptoms.
It is worth noting that a depressive episode in a bipolar patient is tough to distinguish from major depression. However, some authors suggest that there are subtle differences between the two, some of these differences include:
- Higher psychomotor retardation in bipolar disorder
- More difficulty thinking in bipolar disorder
- Increased frequent psychotic symptoms in bipolar disorder
- There is substantial weight loss in unipolar depression
- More initial insomnia in major depression
- More hypersomnia in bipolar depression
Also, several studies suggest that depressive episodes in bipolar disorder are shorter and quicker to onset than those in unipolar depression. Depressive episodes are even more frequent in bipolar disorder than in unipolar depression.
When it comes to gender distribution, both seem to be more common in women than in men. Bipolar disorder tends to have an earlier onset than major depression.
These differences are very subtle. In everyday practice, the only way to differentiate the two is a history of mania or hypomania.
Is there evidence supporting the distinction between unipolar and bipolar disorders?
The medical community is still wondering if a depressive episode within bipolar disorder represents a different disease process than a depressive episode in the context of unipolar depression.
Some authors propose conceptualizing unipolar depression and bipolar depression as part of the same illness. But the fact remains, both diseases respond to different treatments and tend to have a different course.
Also, the diagnosis of bipolar disorder does not necessarily require a depressive episode. Current research suggests the existence of monopolar mania. Around 25% of bipolar disorder patients never report a depressive episode in the course of the disease.
Classically, researchers thought depression is triggered by life circumstances, while bipolar disorder is an endogenous biological process independent from environmental factors. However, recent studies have shown that psychosocial factors also play an essential role in developing bipolar disorder. But this raises the question of how the triggers of bipolar and unipolar depression overlap.
However, there are some biological similarities between the two of them, some of them include:
- Decreased blood flow to the cerebral cortex, the prefrontal cortex in particular
- Abnormal phosphorus metabolism in the frontal cortex
- Decreased metabolic activity in the prefrontal cortex
- Increased activity in the amygdala
- Similar dopamine activity in both bipolar depression and unipolar depression
- Similar serotonin activity in both conditions
Researches are still figuring out the real significance of these findings.
What causes depression?
Depression, like all other mental illnesses, is a complex pathology that results from the combination of many different factors. Genetic predisposition, stressful events, impaired mood regulation in the brain, a serotonin deficit, medications, and comorbid conditions are all forces that ultimately lead to depression.
Here is a list of some of the risk factors for depression:
- Family history: Depression does run in families, and individuals with a family history of depression are more likely to suffer from it. However, it is not the only factor involved. Personal circumstances and life events appear to have as much importance in developing the disease as genetic factors.
- Adverse life events: Continuous difficulties like unemployment, death of loved ones, being diagnosed with a chronic illness, uncaring relationships, and isolation increase the risk of depression.
- Drugs and alcohol use: Substance abuse is both a cause and a consequence of depression. In most patients, it is difficult to determine which one came first.
- Childhood trauma or abuse
- Personality: Certain personality traits like low self-esteem, pessimism, and dependency increase the risk of developing depression.
- History of other mental health disorders.
Is there a gene for it?
There are several diseases caused by a single gene. Most of these diseases are rare and infrequent. Some examples include cystic fibrosis, Huntington’s disease, and several types of muscular dystrophy. Depression is not one of these diseases.
Heredity is a complex interplay of many factors, not just individual genes. Having particular variations of a certain item can make it more likely to develop the condition associated with that variant.
However, this is not definite in any way. Many people experience depression without having any family history of the disease. Also, people with a family history never develop depression.
Several times researchers identify a genetic variant in persons with the disease but don’t know if that variant is significant or not. This is called a variant of unknown significance.
There are plenty of genetic variants that appear to be associated with symptoms of depression. These genes have diverse functions in the brain. Some control the synthesis of neurotransmitters, others have transport functions, and others are involved in the growth and maintenance of neurons.
So far, no study has definitely identified a single gene as the cause of depression. Research into the genetics of depression is still in its early stages.
So far, most researchers agree that depression is not the result of a single gene variant. It is more likely that variations in many genes, each one with a small effect, sum up to increase the risk of suffering from depression.
It is more likely that all the different genetic variables and environmental factors make a small contribution to each person’s overall risk.
How many types are from it?
Many types of major depression can affect daily life. These types have different causes, but most of them involve a lack of interest in everyday activities, a depressed mood, and an overall feeling of melancholy. Some of these disorders include:
• Seasonal affective disorder: The defining characteristic of this disorder is that it has a direct link to the time of the year. It is most common in winter months where sunlight is absent. Light absence appears to be the main trigger of the condition. About half of patients can be effectively treated with light therapy alone. However, the other half do require antidepressant medication.
• Postpartum depression: As you might imagine from the name, this disorder refers to the depression that appears right after childbirth. This disorder is mostly due to hormonal imbalance that characterizes the postpartum period. Interestingly enough, parents who adopt can also suffer some of the symptoms of postpartum depression.
• Atypical depression: The term refers to a depressive state in which affected individuals have an improved mood when experiencing pleasurable experiences. Symptoms include hypersomnia, heaviness, and social anxiety. The grief in atypical depression has some similarities with the grief felt after losing a loved one.
• Catatonic depression: This one is a psychotic disorder that involves motor problems and behavioral issues. Patients with catatonic depression can be immobilized and have involuntary movements. It can severely interfere with a healthy life.
• Depressive Psychosis: Some depressed patients go through periods in which they lose touch with reality. During these periods, they might experience hallucinations and delusions.
• Premenstrual dysphoric disorder: This one is a severe form of premenstrual syndrome (PMS), but while in PMS symptoms tend to be more physical than psychological, in PMDD is the other way around.
What are the symptoms of major depression?
The diagnosis of the major depressive disorder requires a depressed mood that lasts for more than two weeks.
Major depression symptoms are severe enough to cause difficulty in getting through everyday tasks such as going to school, attending social engagements, going to work, and maintaining relationships of any kind.
When a mental health professional suspects depression, he might ask some of the following questions:
- Have you been feeling blue, down, depressed, or irritable?
- Have you lost interest in things?
- Do you get less pleasure from things you used to enjoy?
- Do those periods last over two weeks?
- Did these periods cause significant problems with loved ones, significant others, or family?
- Did you have any problems at work or school during these periods?
The diagnosis requires at least five of the following symptoms:
- Depressed mood: The patient will have a depressed mood for the major part of the day.
- Diminished interest: There is a diminished interest in activities or pleasures the patient used to enjoy.
- Weight problems: It could exist an excessive weight loss or excessive weight gain with changes in appetite
- Sleeping disorders: which could be either difficulty sleeping or too much sleep
- Vague symptoms: Patients usually look wore down or less active than usual, which they manifest as fatigue.
- Excessive guilt: The patient can feel worthlessness or excessive guilt, patients may feel regret or guilt about current or past events and relationships
- A drop in productivity: It affects the work or study environment by having decreased concentration, inability to focus and making decisions
- Suicidal thoughts: Patients could have suicidal thoughts or recurrent thoughts of death.
- Feeling agitated: The feeling of being agitated or slowed down.
Can children have unipolar or bipolar depression?
Unfortunately, children can suffer from both conditions. Statistics suggest that 2% of preschool and school-age children suffer from depression.
In the United States, suicide is the third cause of death among children, adolescents, and young men between the ages of 10 to 20.
Bipolar disorder can occur at any age, as well. Currently, there is no reliable data bout the prevalence and incidence of bipolar disorder in children.
How is a depression in childhood different from depression in adulthood?
As with adults, depression in children doesn’t have a specific cause. It has biological reasons related to a deficiency in serotonin in the brain. Genetics also play an essential role in childhood depression. Teens with a depressed parent are four times as likely to suffer from the condition.
There are psychological contributors, as well. Children with a negative body image, inadequate social skills, and low self-esteem are more likely to suffer from depression.
Depression can also be a consequence of trauma, including sexual abuse, psychological abuse, physical abuse, and bullying. Other important risk factors include poverty, exposure to violence, and parental conflict.
Regardless of age, major depression symptoms include having a persistent depressed mood, difficulty experiencing pleasure, and difficulty getting through everyday activities. Children with depression usually experience classic symptoms but can also exhibit other symptoms, such as:
- Bad performance in school
- Persistent boredom
- Frequent physical complaints, like headaches, stomach aches, etc.
- Risk-taking behavior and lack of concern for personal safety: climbing too high, running carelessly in the street
- Increased sensibly to critics and other negative stimuli.
- Crying often and easily
- Acting younger than their age (regression)
How is bipolar disorder in childhood different from bipolar disorder in adulthood?
As in adults, bipolar disorder in children can cause abrupt mood swings between severe depression, mania, and hypomania.
The diagnosis during childhood and adolescence can be challenging, mostly because of mood swings, hyperactive behavior and irritability are a normal part of being an adolescent.
However, if the child’s symptoms are severe, persistent, and cause important consequences, a mental health issue needs to be taken into consideration. Here is a list with some warning signs of bipolar disorder in children:
- Mania: Mania expressed itself differently in childhood than in adulthood. During childhood, mania can express itself as unusual highs in self-esteem (like the certainty of having special superpowers), an increase in energy with a decreased need for sleep, high risk-taking behavior, rapid thinking, and talking.
- Depressive episodes: See the section above
- Anger and Rage: Children and adolescents generally tend to be more anger prone than adults. However, those with bipolar disorder tend to feel anger at a very intense level. It can manifest into violence, directed towards breaking toys or harming others. Severe rage outbursts can last for hours.
- Severe fluctuations in the mood: In youngsters with bipolar disorder, mood swings tend to be more frequent and abrupt. Many times theses mood swings occur during the same day.
In children, differential diagnosis with other childhood illnesses has to be made. Other conditions that may cause similar symptoms to include the following:
- Attention deficit-hyperactivity disorder (ADHD)
- Anxiety disorder
- Oppositional defiant disorder
- Major depressive disorder
What are the complications of depression?
As with any other disease, depression has some important complications. Even patients that suffer from mild forms of depression can suffer severe complications. Some complications include:
- Worsening of other chronic diseases: Having a chronic disease can lead to depression. At the same time, having depression can further complicate chronic diseases creating a vicious circle. The difficulty of adjusting to the illness’s demands and the impairment of the patient’s mobility and independence are some of the factors that lead to depression in chronically ill patients. Depression, on the other hand, causes more fatigue and demotivation and a lack of interest in getting better and being consistent with treatment.
- Excess weight gain and obesity: This can lead to heart disease, diabetes, and joint disease.
- Alcohol and drug abuse: Depressed individuals are more susceptible than the general population to suffer from drug or alcohol addiction.
- Family conflicts, work issues that may even lead to unemployment, and relationship issues may even cause separation or divorce.
- Social isolation.
- Sexual issues: Both depression and depression medications can cause sexual problems. Depression decreases sex drive, some antidepressant drugs can also decrease libido and sexual functioning.
- Pain: Major depression can manifest itself with physical symptoms like pain. Remember that the mind controls the body, and a person’s emotions can have effects on the body’s major functions. Depression can cause headaches, neck pain, and abdominal pain. This pain is extremely hard to treat.
Can depression turn into bipolar disorder?
No, depression cannot “turn” into bipolar disorder. What happens is that a person previously misdiagnosed with major depressive disorder actually has a type of bipolar depression. Having an accurate diagnosis is vital to provide effective treatment.
Although there are some intrinsic and unique characteristics of each condition, many symptoms of bipolar depression and bipolar disorder overlap.
Bipolar II disorder, in particular, may be hard to differentiate from major depression. These patients experience hypomanic episodes instead of manic episodes, hypomania, in some cases, maybe mild enough for no one in that person’s environment to suspect a mental health issue. Although the manic part of bipolar disorder type 2 is not as severe, depressive episodes tend to be quite frequent and severe, thus causing misdiagnosis.
Substance abuse can also complicate the diagnosis. A depressed person who uses drugs like cocaine and amphetamines can exhibit bipolar disorder without actually having it. Research suggests that misdiagnosis can occur when the clinician is aware of the patient’s history of substance use.
It is also possible for a person who actually has a bipolar disorder not to be diagnosed because symptoms are attributed to a history of drug abuse instead of an underlying mental illness. Because drug abuse is a frequent complication and trigger of psychiatric disorder, misdiagnosis due to drug abuse is very frequent.
Misdiagnosis leads to inadequate treatment. Antidepressants (the treatment of choice for major depression), are not effective in bipolar disorder. In bipolar disorder, antidepressants can actually make symptoms worse, increasing the frequency of manic episodes.
Furthermore, if the patients haven’t had a manic episode so far, antidepressants can trigger it. Bipolar disorder requires a mood stabilizer like lamotrigine or lithium.
How is unipolar depression diagnosed?
Psychiatric disorders like bipolar depression, schizophrenia, and major depression are based on signs and symptoms that meet the diagnostic criteria, not in laboratory or imaging studies. DSM-5 is a manual for assessment and diagnostic of psychiatric conditions by the American Psychiatric Association.
It provides the diagnostic criteria for all the major psychiatric disorders, including depression. DSM is periodically revised and reviewed since 1952. The current version was the result of a decade long process of research evaluation. The team included 160 of the top clinicians and researchers around the world.
Screening tests are not in the DSM-5 and are not diagnostic of depression. However, they are a useful tool to screen for depression in the general population and refer to a mental health professional when needed. The U.S Preventive Services Task Force recommends screening for depression in older adults, pregnant and postpartum women. The two basic questions of a screening test are:
- During the past month, have you been bothered by feeling down, depressed, or hopeless?
- During the past month, have you been bothered by little interest or pleasure in doing things?
These two questions have a sensitivity of 97% and a specificity of 67%. This means that only 3% of the depressed patients that take the tests are not detected and that 33% of patients detected as the test as possibly depressed are not really depressed.
There are many instruments for depression screening. Currently, there is no evidence to claim one instrument is superior. The instrument of choice in each case is the one that is more readily available and more practical at the moment.
Are laboratory studies totally useless in depression?
Although the diagnosis of depression is mostly clinical, laboratory tests are useful to rule out organic or physical causes of depression and medical illnesses that can present themselves as a major depressive disorder. The differential diagnosis for unipolar depression includes many different medical conditions, including:
- Central nervous system diseases: Dementia (i.e., Alzheimer’s disease or vascular dementia), multiple sclerosis, Parkinson’s disease, brain tumor.
- Endocrine disorders: Hypothyroidism and Hyperthyroidism, Cushing syndrome, Hyperparathyroidism, and hypopituitarism.
- Drug abuse: alcohol, cocaine, amphetamines, and cannabinoids.
- Infectious diseases: Mononucleosis
- Sleep disorders: Obstructive sleep apnea in particular
- Drug-related changes: Some antihypertensive medications (reserpine, methyldopa, and beta-blockers), steroids, heartburn medication (ranitidine and cimetidine), chemotherapy agents, sedatives, sex hormones and medications that affect sex hormones (estrogen, testosterone, progesterone), sedatives, muscle relaxants.
Your physician might order some of the following tests to discard any underlying medical condition:
- Complete blood cell count
- Thyroid stimulation hormone (TSH)
- Electrolytes: calcium, phosphate, and magnesium levels.
- Blood urea nitrogen and creatinine
- Blood alcohol tests and blood and urine toxicology screen.
Given their elevated cost and questionable diagnostic values, neuroimaging studies are not the standard of care in depression.
Which therapies help treat unipolar depression?
Medication and psychotherapy are the two cornerstones of depression treatment. Medication or psychotherapy by themselves are not effective, they need to be together for treatment to work.
Combination therapy leads to higher and quicker rates of improvement in depressive symptoms, increase quality of life, and better treatment compliance.
Depression treatment takes around 4- 12 weeks to produce evident changes. Treatment failure is often the consequence of medication noncompliance, inadequate duration of therapy, or inadequate dosing.
What medications are used in depression?
Antidepressant medication is the standard of care for major depression. Treatment usually starts with a low dose that is gradually improved until the patients begin showing improvement.
Your physician will monitor the side effects and measure improvement. The most common antidepressants include:
- Selective serotonin reuptake inhibitors (SSRI): Currently, SSRIs are the most common antidepressant drugs, mainly because they have few and infrequent side effects compared to other alternatives. SSRIs block the reuptake of serotonin in the brain synapsis, thus increasing the availability of serotonin. The most common adverse effects include insomnia, sexual dysfunction, and weight gain. Some examples include fluoxetine, citalopram, paroxetine, and sertraline.
- Tricyclic antidepressants (TCAs): Tricyclic antidepressants work similarly as SSRIs, but with more side effects. Therefore TCAs are only prescribed when other medications at maximal doses fail. TCAs are also used to treat chronic pain. Common side effects include drowsiness, blurred vision, constipation, and drop in blood pressure when moving from sitting to standing, which causes lightheadedness, urine retention, and weight gain due to increased appetite. Some examples include amitriptyline and nortriptyline.
- Atypical antipsychotics: Patients with treatment-resistant depression or very severe depressive disorder can benefit from atypical antipsychotics, which are normally used in schizophrenia and bipolar disorder. In depression, these drugs can help improve mood, sleep, appetite, and energy level. Some examples include quetiapine and olanzapine. Adverse effects include dizziness, extrapyramidal effects, fatigue, drowsiness, increased cholesterol, and triglycerides.
What forms of psychotherapy are used in depression?
Three kinds of therapy have proven to improve depressive symptoms. These include:
- Cognitive-behavioral therapy: Cognitive behavioral therapy (CBT) focuses on identifying and restructuring negative thought and behavioral patterns. It is the most common and more effective form of therapy for depression and anxiety disorder. Contrary to psychoanalysis, which focuses on understanding motivations and reactions, CBT focuses on proactively changing negative ways of thinking. The idea of CBT is teaching patients skills that will last long beyond the end of treatment. Depression usually comes and goes several times over a lifetime. CBT teaches how to cope with stressful life events that can lead to flare-ups. CBT is limited to a certain number of visits, usually ranging from 8 to 16 sessions.
- Psychodynamic therapy: This type of therapy works on the theory that bad patterns and feelings are originated in past experiences. The therapist works with the patient to tap the unconscious processes that have led to current problems. Psychodynamic therapy focuses on the interpretation of mental and emotional processes rather than focusing on behavior as CBT does.
- Interpersonal therapy: This one is a time-limited approach to treat mood disorders. The main goal is to improve the quality of the patient’s interpersonal relationships and social functioning. It can also help manage unresolved grief and help with difficult life transitions such as retirement, separation, or divorce. Despite that, the approach was initially designed to treat the depressive disorder. It is also useful in alcohol addiction, bipolar disorder, dysthymia, and perinatal depression.
Are you having symptoms of it?
This tool is a depression symptoms checker. It gathers the most important signs, symptoms, and risk factors for developing the condition. Therefore, it would tell anybody who uses it the likelihood of having depression. The most important feature of this tool is that it is free and would only take you a few minutes.