Types of Depression in Adults

What is depression?

While we all feel sad, moody or low from time to time, some people experience these feelings intensely, for long periods of time (weeks, months or even years) and sometimes without any apparent reason. Depression is more than just a 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?

What causes depression?

There is increasing consensus that depression is the result of a combination of genetic predispositions (weaknesses in our DNA) interacting with nutrient deficiencies in our modern diet of highly processed foods, foods grown using chemical fertilisers and pesticides, and environmental toxins.   These reduce a person's emotional hardiness, allowing daily hassles chronic stress and adverse life events to precipitate anxiety and/or depression.  Generally, depression does not result from a single event, but from a combination of biological underpinnings interacting with adverse events and other environmental factors.

Adverse life events

Research suggests that stressful ongoing difficulties, long-term unemployment, living in an abusive or uncaring relationship, long-term isolation or loneliness, prolonged exposure to stress at work, are more likely to cause depression than recent life events. However, recent events (such as losing a job) or a combination of negative life events can ‘trigger' depression in people who are already at risk because of reduced emotional hardiness..

Personal factors

  • Family history – Depression can run in families and some people may have an increased genetic risk. However, this doesn't mean that a person will automatically get depressed if depression runs in the family. That person may not inherit the mutated gene associated with depression. Dietary factors, nutrient levels, life circumstances and other factors are still likely to have an important influence on whether that person will be triggered into depression.
  • Personality – Some people may be more at risk of depression because of their personality, particularly if they have a tendency to worry a lot, have low self-esteem, are perfectionists, are sensitive to personal criticism, or are self-critical and negative. This is frequently, but not always, due to frontal brain asymmetry, a problem which can be identified in a Quantitative EEG (QEEG) study, and treated effectively using Neurotherapy.
  • Serious medical illness –A medical illness can bring about depression directly, or can contribute to depression through associated stress and worry, especially if it involves long-term management of the illness 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 problems. Over 500,000 Australians will experience depression and a substance use disorder at the same time, at some point in their lives.

Depression and abnormal brain electrical activity

There has been a lot of research in this complex area, and much has been discovered by Neuroscientists and there is still much more to be discovered. 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 and many of these can be identified in a QEEG, for example: Low brain electrical power in the low frequencies, elevated Alpha waves, frontal Alpha asymmetry, excessive fast waves, globally low power levels.

Types of depression

There are different types of depressive disorders. Symptoms can range from relatively minor, but still disabling for an individual, through to very severe, so it is helpful to be aware of the range of disorders and their specific symptoms.

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. The symptoms are experienced most days and last 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).


This is the term used to describe a severe form of depression where many of the physical symptoms of depression are present. One of the major changes is that the person can be observed to move more slowly. The person is also more likely to have a depressed mood that is characterised by complete loss of pleasure in everything, or almost everything.

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), such as believing they are bad or evil, or that they are being watched or followed. They can also be paranoid, feeling as though everyone is against them or that they are the cause of illness or bad events occurring around them.

Antenatal and 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 the period covered by pregnancy and the first year after the baby's birth.

Recent research points the fact that the baby needs an enormous amount of Omega 3 Essential fatty acids (from oily fish) particularly in the last trimester, and during breastfeeding. Many women have low Omega 3 blood levels as they may be depleted due to they not eating enough deep sea cold water fish. low omega 3 in the brain causes depression in the  days immediately following birth.  The baby's brain requires an enormous amount of Omega 3, and will drag it out of the mother's brain and body if there is not enough in the mother's diet. Nature will always put the baby's needs ahead of the mother's. The 'baby blues', or general stress adjusting to pregnancy and/or a new baby, are common experiences, but are different from depression. Depression is longer lasting and can affect not only the mother, but her relationship with her baby, the child's development, the mother's 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 having a baby. The baby 's brain is still developing and so is the need for Omega 3. If the mother is breastfeeding, the need for Omega 3 for both is still very high.  Much of this is preventable by eating oily fish 2-3 times a week or with an adequate intake of fish oil capsules. In addition certain vitamins and minerals are also needed as co-factors.

Bipolar disorder

Bipolar disorder used to be known as 'manic depression' because the person experiences periods of depression and periods of mania, with periods of normal mood in between. Mania is the opposite of depression and can vary in intensity – symptoms include feeling great, having lots of energy, having racing thoughts and little need for sleep, talking fast, having difficulty focusing on tasks, and feeling frustrated and irritable. This is not just a fleeting experience. Sometimes the person loses touch with reality and has episodes of psychosis. Experiencing psychosis involves hallucinations (seeing or hearing something that is not there) or having 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 episodes for people with this condition and it's not uncommon for bipolar disorder to be misdiagnosed as depression, alcohol or drug abuse, Attention Deficit Hyperactivity Disorder (ADHD) or schizophrenia.

Diagnosis depends on the person having had an episode of mania and, unless observed, this can be hard to pick. It is not uncommon for people to go for years before receiving an accurate diagnosis of bipolar disorder. It can be helpful for the person to make it clear to the doctor or treating health professional that he or she is experiencing highs and lows. Bipolar disorder affects approximately 2 per cent of the population.

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 hypo-mania (a mild to moderate level of mania) and periods of depressive symptoms, with very short periods (no more than two months) of normality between. The duration of the symptoms are shorter, less severe and not as regular, and therefore don't fit the criteria of bipolar disorder or major depression.

Dysthymic disorder

The symptoms of dysthymia are similar to those of major depression but are less severe. However, in the case of dysthymia, symptoms last longer. A person has to have this milder depression for more than two years to be diagnosed with dysthymia.

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 D3 Deficiency. It's 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's usually diagnosed after the person has had the same symptoms during winter for a couple of years. People with Seasonal Affective Disorder depression are more likely to experience lack of energy, sleep too much, overeat, gain weight and crave for carbohydrates. SAD is rare in Australia and 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.

Signs and symptoms of depression

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

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

Behaviours during an episode of depression

  • not going out anymore
  • not getting things done at work/school
  • withdrawing from close family and friends
  • relying on alcohol and sedatives
  • not doing usual enjoyable activities
  • unable to concentrate

Feelings during an episode of depression

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

Thoughts during an episode of 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 an episode of depression

  • tiredness all the time
  • sick and run down
  • headaches and muscle pains
  • churning gut
  • sleep problems
  • loss or change of appetite
  • significant weight loss or gain