There are different types of depressive disorders. Symptoms can range from relatively minor (but still disabling) through to very severe, so it's helpful to be aware of the range of conditions and their specific symptoms.
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, as well as other symptoms. 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 starts to move more slowly. They're also more likely to have a depressed mood that is characterised by complete loss of pleasure in everything, or almost everything.
Sometimes people with a depressive disorder can lose touch with reality and experience psychosis. This can involve hallucinations (seeing or hearing things that aren't there) or delusions (false beliefs that aren't shared by others), such as believing they are bad or evil, or that they're 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.
The causes of depression at this time can be complex and are often the result of a combination of factors. In the days immediately following birth, many women experience the 'baby blues' which is a common condition related to hormonal changes and affects up to 80 per cent of women. 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.
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 like 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 quickly, 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).
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. If you're experiencing highs and lows, it's helpful to make this clear to your doctor or treating health professional. Bipolar disorder affects approximately 2 per cent of the population.
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 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.
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, but it's thought to be related to the variation in light exposure in different seasons. 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 SAD depression are more likely to experience a lack of energy, sleep too much, overeat, gain weight and crave for carbohydrates. SAD is very 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.
Remember, depression is treatable and effective treatments are available. The earlier you seek support, the better.