Depression: Types, Causes & Symptoms

Whilst we all feel sad, moody, or low from time to time, people can experience these feelings intensely, for long periods of time (weeks, months or even years) and sometimes for no apparent reason. Depression is more than just low mood, it's a serious illness that has an impact on both physical and mental health. Antidepressants are commonly prescribed, but do they address the underlying causes? There are different types of depression and each is treated differently depending on the cause of depression. Let us understand all this in detail.

Types of Depression

There are types of depressive disorders. Symptoms range from relatively minor, to functionally disabling, to very severe. Is helpful to be aware of the range of depressive disorders and their specific symptoms.

1. Major Depression

Major depression is sometimes called major depressive disorder, clinical depression, unipolar depression or simply depression. It involves low mood and/or loss of interest and pleasure in usual activities. Symptoms are experienced most days for at least two weeks. Symptoms of depression interfere with all areas of a person's life, including work and social relationships. Depression can be described as mild, moderate, or severe; melancholic or psychotic (see below).

2. Melancholia

This is the term used to describe a severe form of depression where a person is physically observed to move more slowly. This person’s depressive state is characterised by a complete loss of pleasure in everything, or almost everything.

3. Psychotic Depression

Sometimes people with a depressive disorder can lose touch with reality and experience psychosis. This can involve hallucinations (seeing or hearing things that are not there) or delusions (false beliefs that are not shared by others) e.g., believing they are bad or evil, or that they are being watched or followed. They may be paranoid, feeling as though everyone is against them, or that they are the cause of illness or bad events occurring around them.

4. Antenatal & Postnatal Depression

Women are at an increased risk of depression during pregnancy (known as the antenatal or prenatal period) and in the year following childbirth (known as the postnatal period). You may also come across the term 'perinatal', which describes both time periods.

Recent research points to the fact that the baby needs an enormous amount of Omega 3 Essential fatty acids (from oily fish) in the last trimester, and during breastfeeding. Many women have low Omega 3 blood levels, due to not eating enough deep-sea cold-water fish. Low omega 3 in the brain causes depression in the mother. The developing child also needs Omega 3 and will absorb it from the mother's brain and body if there is not enough in her diet. Nature will always put the child’s needs ahead of the mother’s. The 'baby blues', or general stress adjusting to pregnancy and/or a new child, are common experiences, but are different from depression. Depression is longer lasting and not only affects the mother, but her relationship with her child and its development. Depression will also affect her relationship with her partner and with other members of the family. Almost 10 per cent of women will experience depression during pregnancy. This increases to 16 per cent in the first three months after childbirth. The child's brain continues to develop and thus still requires Omega 3. If the mother is breastfeeding, the need for Omega 3 is high for both. The risk of depression is reduced by eating oily fish 2-3 times a week or with an adequate intake of fish oil capsules.

Certain vitamins and minerals are also needed as co-factors for Omega 3.

5. Bipolar Depression

Bipolar disorder used to be known as 'manic depression' because the person experiences periods of depression and periods of mania, with baseline mood states in between. Mania symptoms can include feeling great, having lots of energy, racing thoughts, little need for sleep, talking fast, having difficulty focusing, feeling frustrated and irritable. This is not just a fleeting experience. Sometimes the person loses touch with reality and has episodes of psychosis. Psychosis involves hallucinations (seeing or hearing something that is not there) or delusions (e.g. the person believing he or she has superpowers). Studies indicate that Bipolar disorder responds well to fish oil supplements and nutrient co-factors.

Bipolar disorder seems to be most closely linked to family history. Stress and conflict can trigger bipolar episodes for some. Due to the person’s sharp changes in mood, bipolar disorder is often misdiagnosed as depression, alcohol or drug abuse, Attention Deficit Hyperactivity Disorder (ADHD) or schizophrenia.

Diagnosis often depends upon an identifiable episode of mania and, unless observed, this can be hard to detect. It is not uncommon for people to go for years without an accurate diagnosis of bipolar disorder. It is helpful for the person to make it clear to the doctor or treating health professional that he or she is experiencing both intense highs and lows.

Bipolar disorder affects approximately 2 per cent of the population.

6. Cyclothymic Disorder

Cyclothymic disorder is often described as a milder form of bipolar disorder. The person experiences chronic fluctuating moods over at least two years, involving periods of hypomania (a mild to moderate level of mania) and periods of depression, with very short periods (no more than two months) of normality in between. The duration of the symptoms is shorter, less severe, and less regular, and does not meet criteria for bipolar disorder or major depression.

7. Dysthymic Disorder

The symptoms of dysthymia are like those of major depression but are less severe. However, in the case of dysthymia, symptoms last longer. A person will have experienced some depression for more than two years to be diagnosed with dysthymia.

8. Seasonal Affective Disorder (SAD)

SAD is a mood disorder that has a seasonal pattern. The cause of the disorder is unclear however, it is thought to be related to reduced sunlight exposure in winter, causing vitamin deficiency. It is characterised by mood disturbances (either periods of depression or mania) that begin and end in a particular season. Depression which starts in winter and subsides when the season ends is the most common. It is usually diagnosed after the person has had the same symptoms during winter for a couple of years. People with Seasonal Affective Disorder are more likely to experience lack of energy, sleep too much, overeat leading to weight gain, and crave carbohydrates. SAD is rare in Australia, since it is more likely to be found in countries with shorter days and longer periods of darkness, such as in the cold climate areas of the northern hemisphere. However, avoidance of sunshine and use of sunscreens seem to have increased its incidence in Australia. Aggressive Vit D3 supplementation is used to treat SAD, with blood levels around 180-220 nMols/L recommended as optimum by Vitamin D experts.

Causes of Depression

There is increasing consensus that depression is the result of a genetic predisposition, combined with nutrient deficiencies caused by our modern diet. The modern diet contains highly processed foods, foods grown using chemical fertilisers and pesticides, and environmental toxins. These aspects of poor diet reduce a person's emotional capacity to deal with daily stressors and adverse life events – symptoms which precipitate the development of anxiety and/or depression. Generally, depression is not the result of a single event, but is due to a combination of social, biological, and environmental factors, as well as trauma.

1. Adverse Life Events

Research suggests that ongoing stressors, such as long-term unemployment, being in an abusive or uncaring relationship, loneliness and work dissatisfaction are more likely to cause depression than recent life events. However, recent events (such as losing a job) or a combination of negative experiences can ‘trigger' depression in people who are already predisposed.

2. Personal Factors

  • Family history – Depression often runs in families and some people are at increased genetic risk. However, this does not mean that a person is destined to become depressed if a family member is. Some will not inherit the mutated gene associated with depression. Poor diet and adverse life events are more likely to contribute to depression than genetics alone.
  • Personality – Certain personality differences mean that some people are more at risk of developing depression than others, particularly if they worry a lot, have low self-esteem, perfectionistic tendencies, are self-critical, or sensitive to personal criticism. This is frequently, but not always, due to frontal brain asymmetry, which can be identified in a Quantitative EEG (QEEG) study, and treated effectively with Neurotherapy.
  • Serious medical illness – A medical illness can bring about depression directly or can contribute to depression through associated stress and worry, especially if the illness involves long-term management and/or chronic pain.
  • Drug and alcohol use –Drug and alcohol use can both lead to, and result from, depression. Many people with depression also have drug and alcohol use disorders. Over 500,000 Australians will experience comorbid depression and substance use disorders at some point in their lives.

3. Abnormal Brain Activity

Neuroscientists have conducted research in this complex area, but there is still more to learn. Contrary to popular belief, depression is not simply the result of a ‘chemical imbalance’ between brain messenger chemical (neurotransmitters). There are, in fact, many different brain-based causes of depression which can be identified in a QEEG e.g. low brain power in the low frequencies, elevated Alpha waves, frontal Alpha asymmetry, excessive fast waves, and globally low power levels.

Signs And Symptoms of Depression

A person may be depressed if, for more than two weeks, they have felt sad, down, or miserable most of the time. They may also have lost interest or pleasure in their usual activities, or experienced several of the signs and symptoms below (across at least three categories):

It is important to note that everyone experiences some of these symptoms from time to time and it may not necessarily mean that they are depressed. Equally, not every person who is experiencing depression will have all these symptoms.

Behaviours During Depression

  • not going out anymore
  • not getting tasks done at work/school
  • withdrawing from close family and friends
  • having an alcohol or drug dependence
  • not partaking in activities that they usually find enjoyable
  • unable to concentrate

Feelings During An Episode of Depression

  • overwhelmed
  • guilty
  • irritable
  • frustrated
  • lacking in confidence
  • unhappy
  • indecisive
  • disappointed
  • miserable
  • sad

Thoughts During Depression

  • 'I’m a failure.'
  • 'It’s my fault.'
  • 'Nothing good ever happens to me.'
  • 'I’m worthless.'
  • 'Life’s not worth living.'
  • 'People would be better off without me.'

Physical Symptoms During Depression

  • chronically tired
  • sick and run down
  • headaches and muscle pains
  • churning gut
  • sleep problems
  • loss or change of appetite
  • significant weight loss or gain