Depression: Causes, Signs and signs and symptoms and Remedies

MNT Knowledge Center

Sadness, feeling down, having a loss of interest or pleasure in daily activities – these are symptoms of depression familiar to all of us.

Getting these issues regularly, so they affect existence for time, could signal the treatable condition of depression, instead of a passing episode of “feeling lower” – which many of us feel eventually.

In line with the US Centers for Disease Prevention and Control (CDC), 8% of people over the age of 12 years has depression in any two-week period.1

The Earth Health Organization (WHO) puts depression near the top of this list – it’s the most frequent illness worldwide as well as the leading reason behind disability. The company estimations that 350 million people around the globe are affected by depression.2

Depression is a lot more common among women than men.2

Contents of this article:

  1. What is depression?
  2. Causes of depression
  3. Symptoms of depression
  4. Test and diagnosis
  5. Treatments for depression
  6. Are talking therapies or antidepressants most effective?

Additionally, you will see introductions in the finish of some sections to the recent developments which have been included in MNT’s news tales. Also consider links to details about related conditions.

Fast details on depression

Here are a few tips about depression. More detail and supporting information is incorporated in the body want to know ,.

  • Depression is a mood disorder. The low mood involves sadness and loss of interest that persists beyond the temporary feelings we all have occasionally and is severe enough to interfere with daily life.
  • Worldwide, 350 million people are estimated to have depression and the condition is more common among women than men.
  • Life events such as bereavement produce mood changes that can usually be distinguished from the features of depression.
  • Separate diagnoses include bipolar disorder, psychotic depression, postpartum depression and seasonal affective disorder.
  • The causes of depression are not fully understood but are likely to be a complex combination of genetic, biological, environmental and psychosocial factors.
  • In addition to the mental symptoms, such as inappropriate feelings of guilt, physical ones may include problems with sleep and a loss of energy.
  • Diagnosis is usually made by a doctor conducting a structured interview to ask specific questions to rate levels of depression, if present.
  • Treatments include psychological treatments, including cognitive behavioral therapy and interpersonal psychotherapy, and drug therapies, including a range of antidepressant classes.
  • Whether drug or talking therapies, or both, are the most appropriate treatment depends on the individual, and they are similar in efficacy.

What is depression?

Depression is really a mental health disorder, a psychological condition. Particularly, it’s a mood disorder characterised by regularly low mood by which there’s a sense of sadness and lack of interest.3,4

Depression is famous by different medical terms, most of which signify a specific diagnosis:4-6

[depressed woman at breakfast]
Depression can affect appetite.

  • Clinical depression
  • Major depression
  • Major depressive disorder
  • Persistent depressive disorder
  • Dysthymia
  • Dysphoric disorder.

Depression is a persistent problem, not a passing one – the average length of a depressive episode is 6 to 8 months.3

Depression is different from the fluctuations in mood that we all experience as a part of a normal and healthy life. Temporary emotional responses to the challenges of everyday life do not constitute depression.3

Likewise, the sense of grief caused by the dying of somebody close or any other type of loss isn’t itself depression if it doesn’t persist.5 Depression can, however, be associated with death – when depression follows a loss of revenue, psychologists refer to it as a “complicated death.”7

Similarly, frustrated mood that is a result of the disappointment of the existence event like a financial problem, a significant illness, or perhaps participation inside a natural disaster, doesn’t always mean depression.5

Unipolar versus bipolar depression

A separate condition may be diagnosed if it is characterized by both manic and depressive episodes separated by periods of normal mood, in which case the mood disorder is not depression but bipolar disorder, which used to be known as manic depression or manic-depressive illness.2

Unipolar or major depressive disorder is estimated to be 3.5 times more prevalent than bipolar spectrum disorders.8

Unipolar depression may be described as mild, moderate, or severe, and can involve anxiety and other symptoms – but no manic episodes. However, nearly 40% of the time over a 13-year period, individuals with bipolar disorder are depressed, making the two conditions difficult, and important, to distinguish.8

Psychotic depression

[screaming newborn baby]
Depression brought on by the birth of a baby is a separate diagnosis.

This diagnosis is characterized by depression accompanied by psychosis.6

Psychosis can involve delusions – false beliefs and detachment from reality – or hallucinations – sensing things that do not exist.

Postpartum depression

Women often experience the “baby blues” with a newborn, but postpartum depression – also known as postnatal depression – is more severe and estimated to affect about 1 in 10 women who have given birth.6

Seasonal affective disorder

Often abbreviated to SAD, seasonal affective disorder is related to the reduced daylight of winter – the depression occurs during this season but lifts for the rest of the year and in response to light therapy.6

Countries with long or severe winters seem to be affected more by SAD.5

Causes of depression

The causes of depression are not fully understood and may not be down to a single source. Depression is likely to be caused by a complex combination of factors:3,5,6,9

  • Genetic
  • Biological – with changes in noradrenergic, dopaminergic and serotonergic neurotransmitter levels theorized
  • Environmental
  • Psychological and social/psychosocial.

Some people are at higher risk of depression than others – risk factors, which play into the above causes, include:3,5,6,9

  • Life events – for example, unemployment, divorce, poverty, although these events lead to lasting, severe depression usually only in people predisposed to it
  • Personality. Failure of adaptive mechanisms/coping strategies to stressors
  • Genetic factors. First-degree relatives of depressed patients are themselves at higher risk, and occurrence of depression between identical twins is high. Genetic factors may influence individual responses to events that trigger depression
  • Childhood trauma can cause long-term brain changes affecting responses to fear and stress. Other history also raises the risk, including a suicide attempt, or any form of abuse – sexual, physical or substance
  • Some prescription drugs – including corticosteroids, some beta-blockers, interferon, and reserpine – can lead to depression.
  • Abuse of recreational drugs – including alcohol, amphetamines – can accompany depression or result in it. There is a high level of comorbidity between drug abuse and depression
  • A past head injury
  • Past diagnosis of depression – people who have had an episode of major depression are at higher risk of a subsequent one
  • Chronic pain syndromes in particular, but also other chronic conditions, such as diabetes, chronic obstructive pulmonary disease, cardiovascular disease.

On the next page we look at the symptoms of depression and how it is diagnosed. On the final page we discuss the treatments available to those suffering with depression.


MNT Knowledge Center

(Continued from page 1…)

Symptoms of depression

The criteria used to make a diagnosis of depression are based on the symptoms that are present, so the list of possible symptoms is similar:3,5,10

  • Depressed mood – feeling sad or low
  • Reduced interest or pleasure in activities previously enjoyed, loss of sexual desire
  • Unintentional weight loss (without dieting) or low appetite
  • Insomnia (difficulty sleeping) or hypersomnia (excessive sleeping)
  • Psychomotor agitation (for example, restlessness, pacing up and down), or psychomotor retardation (slowed movements and speech)
  • Fatigue or loss of energy
  • Feelings of worthlessness or guilt
  • Worsened ability to think, concentrate or make decisions
  • Recurrent thoughts of death or suicide, or attempt at suicide.

Signs are the features that may be noticed by the doctor and others – as opposed to the symptoms that patients can describe themselves. Signs of a person with depression include:5

  • Appearing miserable, tearful eyes, furrowed brows, down-turned corners of the mouth
  • Slumped posture, lack of eye contact and facial expression
  • Little body movement, and speech changes (for example, soft voice, use of monosyllabic words)
  • Gloomy, pessimistic, humorless, passive, lethargic, introverted, hypercritical of self and others, complaining.

The YouTube video below is produced by the National Alliance on Mental Illness – it gives a picture of the features of depression.

Tests and diagnosis of depression

Diagnosis of depression starts with a consultation with a general practitioner or mental health specialist (psychologist or psychiatrist).3

It is important to seek the help of a health professional to rule out different causes of depression, ensure an accurate differential diagnosis, and secure safe and effective treatment.

As for most visits to the doctor, there may be a physical examination to check for physical causes and coexisting conditions. Questions will also be asked – “taking a history” – to establish the symptoms, their time course, and so on.

For depression, a number of structured interviews have been designed to ask questions that are sensitive toward making the diagnosis. These range from one questionnaire that involves just two questions to test for the two “core” symptoms of depression:3


  • Over the past month, have you often been bothered by feeling down, depressed or hopeless?
  • Do you have little interest or pleasure in doing things?


Doctors may also follow the criteria set out by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).4

Here, depression is diagnosed if five or more criteria are met, from a list of nine, and represent a change from normal and have been present for the past two weeks.11

At least one of the symptoms must be one of the two above – that is, either depressed mood or loss of interest or pleasure. The full list of criteria are:3,11

[depressed man]
Low mood for most of the day every day is one of the flags for depression.

  • Depressed mood most of the day, nearly every day
  • Noticeably reduced interest or pleasure in all, or almost all, activities most of the day, nearly every day
  • Significant unintentional weight loss or low appetite nearly every day
  • Insomnia or hypersomnia nearly every day
  • Psychomotor agitation (for example, restlessness, pacing up and down), or psychomotor retardation (depressed body movements, speech, reaction times) nearly every day
  • Fatigue or loss of energy nearly every day
  • Feelings of worthlessness or guilt nearly every day
  • Worsened ability to think or concentrate, or indecisiveness, nearly every day
  • Recurrent thoughts of death or suicide, or attempt at suicide.

The five or more symptoms must be severe enough to affect daily activities or social interactions, or cause significant distress. It must not be possible to explain them by another medical condition, substance use or other causes.3,11

For example, dementia may present as depression, and vice versa. However, memory testing can distinguish the two, so people being investigated for depression may be asked to answer questions that test their cognitive abilities.3

Other underlying causes of depression that should be diagnosed and treated include:3,5

  • Carbon monoxide poisoning
  • Substance misuse (alcohol, anabolic steroids, cannabis, cocaine, narcotics)
  • Prescription drug side-effects
  • Hypothyroidism
  • Brain tumor
  • Parkinson’s disease
  • Vitamin deficiency.

[Depression questions during therapy]
Questionnaires help to diagnose depression and its severity.

Some questionnaires help doctors to assess the severity of depression. The Hamilton depression rating scale, for example, has 21 questions, with resulting scores picking up normal (a score of 7 or below) and mild or moderate depression, to severe or very severe.8

The Hamilton scale is the most widely used assessment instrument in the world for clinicians rating depression.8

A similar questionnaire is available online for patients to rate their own depression and severity as an indication of whether they should see a doctor or therapist – it does not provide a definitive diagnosis but can be used to “start a conversation” with a doctor.12

The depression screening tool provided by Mental Health America is interactive and returns an indication once all the questions are answered. Submitting other demographic details is optional, purely for the non-profit’s research purposes.

Depression or grief? Differential diagnosis

Major depression and grief over the death of a loved one share common symptoms but it is possible to distinguish a grief reaction from depression.

For example, suicidal thoughts or profound and inappropriate guilt are rare with normal bereavement, and self-esteem tends to be maintained.3,10

Other distinguishing features may be that grief comes in waves, whereas depression is constant and unremitting. Or the person suffering a bereavement is able to look forward to the future, whereas a depressed person has no positive feelings for the future.3

Recent developments on treating depression from MNT news

Online CBT unlikely to benefit patients with depression, study finds

For people with depression, cognitive behavioral therapy is deemed an effective treatment option. When it comes to the computerized form of the therapy, however, a new study suggests it offers little or no benefits for individuals with the condition.

Study provides new insight to antidepressant’s effect on immune system

New research published in the Journal of Psychiatric Research investigates a potentially neuroprotective role of escitalopram, a common antidepressant drug.

Ketamine and depression: too much too soon?

Major depressive disorder affects around 14.8 million people in the US, making it the leading cause of disability for people aged 15-44. Could ketamine offer some welcome respite?

CBT and antidepressants ‘equally effective’ for major depression

Cognitive behavioral therapy and second-generation antidepressants are equally effective as treatments for major depression, according to new, evidence-based clinical guidelines published in the Annals of Internal Medicine.


On the next page we look at the symptoms of depression and how it is diagnosed. On the final page we discuss the treatments available to those suffering with depression.


MNT Knowledge Center

(Continued from page 2…)

Treatments for depression

Depression is a treatable mental illness that can usually be managed in primary care by a general practitioner, but may be the subject of care by a specialist – a psychiatrist for, example. There are three components to the management of depression:3,5

  • Support – ranging from discussing practical solutions to contributing stresses, to educating family members
  • Psychotherapy – also known as talking therapies, such as cognitive behavioral therapy (CBT)
  • Drug treatment – antidepressants.


Psychological or talking therapies for depression include cognitive-behavioral therapy (CBT), interpersonal psychotherapy and problem-solving treatment.2

In mild cases of depression psychotherapies are the first-line option for treatment; in moderate and severe cases they may be an adjunctive therapy with other treatment.2,5,6

CBT and interpersonal therapy are the two main types of psychotherapy used in depression. Both talking therapies are present-focused and encourage the regaining of control over mood and functioning:6,7

  • CBT helps to correct negative thought patterns
  • Interpersonal therapy looks at the effect of relationships.

CBT may be delivered in individual sessions with a therapist, face-to-face or over the telephone, but it can also be completed via a computer or in groups. Computerized cognitive behavioral therapy is promising in reducing depression symptoms in young people.13 Sessions typically last one or two hours each week for two to four months.3

We have a special page with more detailed information about cognitive behavioral therapy. Also see below for information about how cognitive therapy compares with antidepressant treatment.

Interpersonal therapy helps patients to identify emotional problems that affect relationships and communication, and how these in turn affect mood and can be changed.14

Interpersonal therapy sessions – conducted over a limited number of weeks – will involve the therapist gaining trust before asking about symptoms and relationships, both through asking questions and providing questionnaires.15

Antidepressant medications

Antidepressants are drugs available on prescription from a doctor, whether one providing primary care treatment, or a psychiatrist.

In mild cases of depression, antidepressants are not generally the first-line option for treatment – in which case, psychological therapy may be recommended first.2

Drugs come into use for moderate to severe depression, but are not recommended for children, and will be prescribed only with caution for adolescents.2

A choice of antidepressant medications is available – the individual selection is a matter of personal preference, previous success or failure, adverse side-effects, whether overdose is likely and could be a danger, and interaction with any other treatments being used.3,5

A number of classes of medication are available in the treatment of depression:16

  • Selective serotonin reuptake inhibitors (SSRIs) – citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), paroxetine (Paxil, Pexeva), sertraline (Zoloft)
  • Monoamine oxidase inhibitors (MAOIs) – isocarboxzaid (Marplan), phenelzine (Nardil), selegiline (Emsam skin patch), tranylcypromine (Parnate), tranylcypromine (Phenelzine)
  • Tricyclic antidepressants – amitriptyline (Elavil), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil), trimipramine (Surmontil)
  • Atypical Antidepressants – bupropion (Wellbutrin), maprotiline, mirtazapine (Remeron), nefazodone, trazodone
  • Selective serotonin and norepinephrine reuptake inhibitors (SNRI) – desvenlafaxine (Pristiq), duloxetine (Cymbalta) venlafaxine (Effexor).

Each class of antidepressant acts on a different neurotransmitter – SSRIs, for example, increase the production of serotonin in the brain, while MAOIs block an enzyme that breaks down neurotransmitters. The exact way in which antidepressant medications work is not fully understood.16

SSRIs are usually tried first, and one in the class can be switched for another that has not proven helpful. Other classes can also be switched in to find effect.3,5

Antidepressant drugs need to be taken for some time before there is effect – typically 2 to 3 weeks – and continued for 6 to 12 months.5,16 The drugs should be continued as prescribed by the doctor, even after symptoms have improved, to prevent relapse.6

A warning from the US Food and Drug Administration (FDA) says that “antidepressant medications may increase suicidal thoughts or actions in some children, teenagers, and young adults within the first few months of treatment.”17

Any concerns should always be raised with a doctor – including any intention to stop taking antidepressants.

Less severe adverse side-effects commonly experienced by people taking antidepressant medication include:16

  • Headache
  • Night sweats
  • Nausea
  • Agitation
  • Sexual problems
  • Dry mouth
  • Constipation.

St. John’s wort, exercise and other therapies

St. John’s wort is a herbal treatment (Hypericum perforatum) that may be effective for mild drepression although the evidence is mixed, and it should be noted that it can interact with other drugs, including antidepressants.5,6

Aerobic exercise may help against mild depression since it raises endorphin levels and stimulates the neurotransmitter norepinephrine, related to mood.9

Brain stimulation therapies – including electroconvulsive therapy detailed below – are also used in depression. Repetitive transcranial magnetic stimulation – that sends magnetic pulses to the brain – is one that may be effective in major depressive disorder.5,6

Mind-body therapies recommended by complementary and alternative practitioners include:4

  • Acupuncture
  • Relaxation techniques such as yoga or tai chi
  • Meditation
  • Guided imagery
  • Massage therapy
  • Music or art therapy
  • Spirituality.

Electroconvulsive therapy

Severe cases of depression that have not responded to drug treatment may benefit from electroconvulsive therapy (ECT), which is particularly effective for psychotic depression.5 MNT has produced detailed information about the treatment on the page about electroconvulsive therapy.

Are talking therapies or antidepressants most effective for depression?

All medical treatments are prescribed against the individual suitability of the treatment for the person, and the same is true in depression.

For some patients it may be a simple matter of choice – perhaps antidepressants are more convenient for some than talking therapies. Another person, meanwhile, may prefer to avoid drug treatment.

If there is a question of choosing one or other option based on effectiveness alone, one study tested whether cognitive therapy had an enduring effect and compared this against continued antidepressant medication.18

The conclusion of the 2005 report, published in the journal JAMA Psychiatry, was:

“Cognitive therapy has an enduring effect that extends beyond the end of treatment. It seems to be as effective as keeping patients on medication.”

The study also cited evidence that CBT is associated with less relapse to depression after treatment than medication.

Another comparison looked at mindfulness-based cognitive therapy and found that it offered a level of protection similar to antidepressant drugs against relapses of depression.19

The trial results were published in The Lancet in April 2015, as reported by MNT. The conclusion was:

“Both treatments were associated with enduring positive outcomes in terms of relapse or recurrence, residual depressive symptoms, and quality of life.”

Recent developments on depression from MNT news

Study identifies symptoms of suicide risk for people with depression

A new study finds behavior patterns such as risky behavior, psychomotor agitation and impulsivity occur before 50% of suicide attempts.

Sleep apnea ‘could be misdiagnosed as depression’

More than 70% of people with sleep apnea experience symptoms of depression, according to a new study published in the Journal of Clinical Sleep Medicine. Researchers say their findings indicate a possibility that the sleep condition could be misdiagnosed as depression.

Lack of face-to-face contact almost doubles depression risk for older adults

Older adults who have little face-to-face contact with family and friends are at almost twice the risk of developing depression, according to a new study published in the Journal of the American Geriatrics Society.

Depression may pass from mothers to daughters

Depression appears to be passed down from mothers to daughters, say researchers who have been looking at similarities in brain structures between generations. The research is published in the Journal of Neuroscience.