What is Depression - Types, Causes and Treatment

At a glance:

  • Depression, in its varying degrees, can be a serious condition that sees people experience low emotional states for long periods of time
  • Long term depression impacts people’s lives related to work, school, social or personal relationships
  • Over 264 million people worldwide experience depression every year
  • Around 1 million Australians experience depression any given year
  • 1 in 6 women and 1 in 8 men experience depression
  • Properly diagnosed depression is typically referred to as major depression or clinical depression
  • Although it is called major depression, depression can actually be classified as mild, moderate, severe or as featuring melancholia or psychosis
  • 10% of women experience antenatal depression (depression during pregnancy)
  • 16% of women experience postnatal depression (depression after the birth of a child)
  • There is no known direct cause of depression but a number of factors, including lifestyle and genetics can increase the chance of someone experiencing depression
  • Depression can be managed with therapy and/or in some cases, medication

What is Depression?

We all feel sad or down at different points in our lives, and feeling this way is a natural part of the human condition, particularly if we are facing significant life stressors.  Depression exists in varying degrees and it becomes serious when the sadness or low moods persist for a long time.  Long-term depression is a potentially debilitating condition that can overwhelm both our mental wellbeing and our physical health.

Depression is a common mental health condition worldwide, with the 2017 Global Burden Disease Study estimating that over 264 million people live with some form of depression. In any given year, around 1 million Australians experience depression, with women being slightly more likely to develop the condition. Roughly one in six women and one in eight men will experience depression at some time in their lives.

Depression can be diagnosed as a clinical depression or a major depressive disorder where people experience low emotional states and sadness for long periods of time. Some people living with depression feel intense self-loathing during these depressive periods, while others feel numb or distanced from any feelings of joy. Depression is an individual experience with a range of unique symptoms.  People suffering from depression, regardless of their individual symptoms, are encouraged to seek the help of a caring professional to help explore what might be going on.  

It is important to make the distinction between experiences of grief and loss, and depression.

With grief and loss, we tend to dip in and out of our sadness to varying degrees, experiencing them as waves rather than all-consuming sadness over longer periods.  For example, we may experience intense sadness in one moment, and find something funny in a movie soon afterwards. 

Types of Depression

Depression is classified by severity as well as by type.  

Major Depression (Clinical Depression)
Although properly diagnosed depression is often referred to as Major Depression, this is not an indicator of severity. Major or clinical depression can be mild, moderate, or severe, as well as having additional symptoms such as melancholy or psychosis. 

The symptoms of major depression typically occur most days during a depressive period, and the depression lasts for two weeks or more. 

Melancholia (Depression with Melancholy)
Melancholia is a severe form of depression characterised by physical symptoms, including slowness of movement, and a loss of pleasure in general.

Depression with Psychosis
Severe depression can sometimes lead to a break with reality and result in a psychosis. During a psychotic episode, a person may experience aural or visual hallucinations, delusions (particularly delusions of persecution - the belief that they are being punished for something or alternately that they themselves are the cause of bad things going on around them) and paranoia.  Depression can also be experienced or seen as a spiritual awakening, with associated transpersonal experiences that need to be explored with a sensitive and caring professional.

Antenatal and Postnatal Depression
Due to massive changes in hormones as well as physical and mental stress, pregnant women as well as women who have recently given birth are at risk of depression. Antenatal depression refers to depression experienced during pregnancy, and postnatal depression is depression experienced after the birth of a child. Depression experienced throughout pregnancy and after the birth of a child is sometimes referred to as perinatal depression.

Postnatal depression can affect not only a mother’s mood but her relationship with the baby and the baby’s development as well. Around 10% of women experience antenatal depression, with the number of women experiencing postnatal depression in the first three months after birth rising to around 16%.

Bipolar Disorder
Bipolar disorder (BPD) , formerly known as “manic depression” is a chronic mental health condition characterised by extreme changes in mood that can last for days or weeks at a time. A person with bipolar disorder cycles between periods of feeling very “high” or euphoric (mania) and extremely low periods (depression), often without an identifiable triggering event.

As depression is the most common first exhibited symptom of bipolar depression, many people with BPD are initially incorrectly diagnosed with clinical depression.

Seasonal Affective Disorder
Seasonal Affective Disorder (SAD) is a kind of depression that is influenced by the seasons. Most people with seasonal affective disorder experience their periods of depression during the colder seasons - Autumn and Winter - whereas only around 10% of people with SAD are triggered by the warmer seasons.

Symptoms differ depending on the seasons that trigger seasonal affective disorder, with those triggered by the cold seasons being more prone to fatigue, sadness, loss of interest and weight gain, and those triggered by spring and summer are more likely to display anxiety, agitation, insomnia and weight loss.  

Dysthymic Disorder
The symptoms of dysthymia are similar to those of clinical depression but are typically less severe but far more long lasting. To be diagnosed with dysthymic disorder, a person must have experienced symptoms of depression for at least two years.

Symptoms of Depression

Depression can make it difficult to function normally in everyday life, impacting our relationships, work, social life and study. 

Symptoms of depression can be broken into a number of categories; feelings, behaviours, thoughts, physical and spiritual.

Many people will experience some of the following symptoms and are encouraged to seek professional help if some of these symptoms persist beyond two weeks.


  • Sadness 
  • Overwhelm by normally routine tasks
  • Miserable, without obvious cause
  • Indecisiveness or inability to make decisions
  • General unhappiness
  • Frustration
  • Irritability
  • Difficulties with concentration
  • General disappointment, either inwardly facing or outward facing
  • Feelings of guilt or worthlessness
  • A lack of confidence or feeling of worthlessness


  • Suicidal ideation - thoughts of suicide and escape through death, or that life just isn’t worth living
  • Thought of being a burden on those around them and the belief that everyone would be better off if they just removed themselves from the picture
  • Belief that they are a failure or can never achieve anything that will bring them happiness
  • Belief that there is nothing good in their life or that nothing good ever happens to them
  • Belief that they have no worth to themselves or anyone else
  • Belief that what they are experiencing is their own fault or that they deserve their bad experiences
  • Belief that their depressed state will never change


  • Social withdrawal - distancing themselves from family and friends
  • Isolation - avoiding going out or leaving a place of safety
  • Self-medication with alcohol, sedatives or other drugs, porn, excessive exercise, gambling or excessive shopping in order to manage or escape
  • Inability to perform at work or study
  • Meaningless - no longer finding fulfilment in activities that once brought joy 

Depressive Physical Symptoms

  • Fatigue or constantly being tired
  • Headaches
  • Muscle pain
  • Nausea
  • Changes in appetite - loss of appetite or overeating
  • Weight change - significant loss or gain of weight
  • Problems with sleep - insomnia, hypersomnia or broken sleep
  • A general feeling of being “sick” 

What Causes Depression?

As is the case with most mental conditions, the exact cause of depression is unknown, but a number of biological, personal and lifestyle factors can increase the chance of a person developing depression during their lifetime.

Much research has been done into the neurochemical causes of depression and as it stands the results are inconclusive. An imbalance in neurotransmitters doesn’t appear to be the cause of depression but it is believed that imbalances in brain chemicals can contribute to the development of the condition. 

These changes in the brain can be due to genetic, lifestyle and personal factors:

  Genetic Factors

  • Heredity - depression runs in families and people with a direct relative with depression are more likely to develop depression than those without. Having more than one relative with depression does not appear to increase chances of developing depression.
  • Genetic Predisposition - Some people appear to have a genetic predisposition to developing a brain chemical imbalance even without any hereditary depression.  
  • Pregnancy - massive changes in hormones during pregnancy, combined with both physical and mental stress can lead to women experiencing antenatal depression. 

Personal Factors

  • Personality - certain personalities appear to be more at risk of developing depression than others. People prone to worry, perfectionism, negativity or self-criticism, and those that have low self-esteem or are particularly sensitive to failure or criticism appear to be more likely to experience depression.
  • Medical Conditions or Injury - Serious injury or medical conditions can directly lead to depressive thoughts or feelings, or can contribute to stressors that can lead to depression. Long term conditions that require constant monitoring or management (especially if pain is involved) can be extremely stressful.
  • Stressors - continuing difficulties or negative life events can increase the chance of a person experiencing depression, especially if they have underlying genetic factors that can increase their chances of developing the condition. Stressors such as long-term unemployment, divorce, the birth of a child, the death of a loved one or being diagnosed with a serious illness can lead to the development of or trigger depression.
  • Medication - some medications, such as blood pressure drugs or hormone replacements can trigger depression, as can some drug interactions.
  • History of Trauma - unprocessed developmental trauma and trauma in later life can have a significant impact on a person. 

Lifestyle Factors

  • Drugs and Alcohol - people living with depression may have drug and/or alcohol problems, and heavy use of drugs and alcohol can also contribute to the development of depression.

Treatment options for people with clinical depression include medication and psychological therapy depending on the severity of the condition.

Seeking good psychotherapy or counselling, or Making an appointment with a doctor for a mental health care plan is encouraged.

Psychological Therapies
A number of psychological therapies can help treat people living with depression. Psychological approaches vary due to severity of the condition and other case to case specific.

  • Cognitive Behavioural Therapy (CBT) CBT is a form of therapy designed to modify unhelpful thoughts and behaviours that may contribute to depression and to provide skills to manage depression symptoms. During CBT sessions, people living with clinical depression can learn to identify and challenge their depressive thoughts and behaviours and replace them with more helpful ways of thinking. Relaxation strategies (e.g., relaxation breathing and muscle relaxation techniques) are also commonly used. Acceptance and Commitment Therapy (ACT) and Dialectical Behavioural Therapy (DBT) are the third wave of CBT, and are also popular and effective approaches.
  • Mindfulness-Based Cognitive Therapy (MBCT) Adapted in part from Buddhist meditation, mindfulness based cognitive therapy can be useful in stabilising mood and preventing a relapse of depression. Usually delivered in a group format, MBCT teaches people to be aware of the current moment while not making judgements, especially self-reflexively negative ones.  MBCT, along with ACT and DBT, encourages the awareness and cultivation of self-compassion. 
  • Psychotherapy Psychotherapy works at a deeper level, with a focus and intention on long-term structural changes within.  There is an exploration of interpersonal and intrapsychic dynamics and the therapeutic relationship can journey (but not always) through earlier life experiences.

Medication Antidepressant medications are sometimes prescribed to manage depression and its related symptoms. Medications include:

  • Selective Serotonin Reuptake Inhibitors (SSRI) - SSRIs are the most commonly prescribed antidepressant drug in Australia due to most people on them experiencing few if any side effects. SSRIs are typically non-drowsy.
  • Serotonin and Noradrenaline Reuptake Inhibitors (SNRI) - typically prescribed for severe depression, SNRIs also have relatively few side effects and are difficult to overdose on.

Other medications are prescribed in specific circumstances, such as a person experiencing symptoms of anxiety as well as depression or in the case of bad side effects from other medications. Mood stabilisers and tranquilisers may also be prescribed where needed.

Side Effects
While antidepressants can help with some symptoms, relapse and duration of depression, people may experience side effects while taking them. Common antidepressant side effects include:

A number of common symptoms, such as dry mouth and dizziness are usually short lived and dissolve after a few days or weeks of starting the medication.

If you, or someone you love, is experiencing depression, seeking help from a good professional is encouraged. There are a number of free services offering help and advice, including Beyond Blue , Lifeline , The Black Dog Institute and Reach Out .

If you would like to book a doctor’s appointment for a mental health care plan, or need to find a psychologist , psychotherapist or counsellor to help support your mental health, an easy  accessible way to do this is to book online via MyHealth1st .

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