Depression is more than feeling low. It’s a serious illness that affects your mental and physical health.

Depression affects how you think, feel and behave causing feelings of sadness and loss of interest in every-day activities, and lasts for two weeks or more.

The signs of depression can range from lowered self-esteem to changes in appetite or weight, changes to sex drive, poor concentration and memory, lower energy levels and a lack of motivation, while you are also less likely to experience feelings of happiness.

At any one time in Australia, it's estimated three million people are living with depression or anxiety.

Dr Jan Orman, GP services consultant at Australian not-for-profit organisation the Black Dog Institute, says while most people will experience depression at some stage in their lives, some people are more vulnerable to depression than others.

“Some of that is because of genetic predisposition to mood disorders and some of it is because of personality predisposition to depression - people like perfectionists and anxious worriers are much more prone to getting depressed, even if they don’t have the genes for depression, than somebody who is a much more relaxed personality.”

People are also more at risk of developing depression if they are have a medical illness or have experienced significant life stress or trauma.

Types of depression

The Diagnostic and Statistical Manual of Mental Disorders - the DSM-5, refers to depression as Major Depressive Disorder (MDD).

While depression is traditionally viewed as a single entity, where the condition is determined by its severity level and length of presence, the Black Dog Institute has developed an alternative hierarchical model designed to identify the particular types of depression and their causes - whether the causes are biological, psychological or other.

The organisation suggests treatments are then tailored to the specific type of depression and its causes.

The Black Dog Institute’s model outlines four types of depression:

Melancholic depression. This is a more severe depression which is also defined by psychomotor disturbance, such as low energy, poor concentration or slow movements. This biological depression affects less than 10 per cent of people with a depression diagnosis. The organisation says it responds best to physical treatments, such as antidepressant medication, and only minimally responds to other treatments such as counselling or psychotherapy.

Psychotic depression. This is the least common type of depression. It is characterised by an even more severely depressed mood, a more severe psychomotor disturbance compounded by psychotic symptoms, such as delusions or hallucinations. It only responds to physical treatments.

Non-melancholic depression. Estimated to account for up to 90 per cent of depression, this type of depression is characterised by a depressed mood and social impairment, such as difficulty in dealing with relationships or work. This type of depression is often linked to stressful life events or in conjunction with the person’s personality style, and responds well to different sorts of psychological treatments, while antidepressant medications can also be used.

Atypical depression. This type of depression has characteristics that contrast with some of the usual characteristics of depression. People are able to experience happiness through some events, have significant weight gain or increase in appetite, experience excessive sleeping and typically also feature a personality style where they are quick to believe others are rejecting them.

Dr Orman says people will get better from depression over time, regardless of the type of depression they experience.

“But sometimes that time can be many years and in the meantime they’ll have done awful things to their lives and their relationships - it will have interfered with their academic progress for example in teenagers, or in adults it will interfere with their careers.”

Looking for depression

Dr Orman says nurses, midwives and allied health professionals should continually be on the lookout for patients experiencing depression.

While some patients will present with visible signs of depression, such as being physically slow or having difficulty answering questions, others will present with signs that are often easily missed.

“Personality styles drive the way someone with depression’s non-melancholic depression will appear when they present, so the anxious worrier will present anxious and worried but more anxious and worried than usual because their depression is driving the increase in anxiety,” she says.

“The perfectionists will present with an inability to complete tasks because they can’t get anything right. Depression provides an amplification of certain aspects of personalities, particularly anxious worrying and irritability.

“Don’t leave depression out of your assessment of a patient, even when you’re assessing them for physical illness because people with physical illnesses are more likely to get depressed.”

Dr Orman says there a range of screening tests health practitioners can use that may indicate a risk of depression, including the self-report K10 and the Depression, Anxiety, Stress Scales (DASS) questionnaire, as well as the Edinburgh Postnatal Depression Scale (EPDS).

She says nurses, midwives and allied health professionals should refer to GPs for a proper medical assessment, as some illnesses can present similar to depression, such as thyroid problems. The GP will then decide whether to refer to a psychologist.

Discuss suicidality

When health practitioners find depression, they should ask about both depression and suicide, Dr Orman says.

“Suicidality is a separate issue and can occur in the absence of depression and when depression is really only mild on clinical assessment.”

While it’s a difficult conversation to have, Dr Orman advises practitioners to discuss suicide. One way, is using the third party questioning technique.

“As an example, you can say… ‘As you know, I think you are suffering from depression. A lot of people in this situation when they are feeling depressed and sometimes when they just feel low, think that life isn’t worth living and begin to have suicidal thoughts. Have you experienced that during this time when you’ve been feeling low?’

Dr Orman says this technique externalises depression and normalises suicidality as something that people with depression may be considering.

“That initial question, which makes it a normal part of being depressed, actually opens the door to the rest of the suicide assessment questions,” she says.

“There’s plenty of evidence that asking about suicide does not increase the likelihood that someone will suicide. In fact, most people who have been close to suicide say that someone opening the door and allowing them to talk about it was a great relief to them - it actually defused the situation for them.”

Resources on depression

There are a range of online resources for nurses, midwives and allied health professionals on depression, and resources and information for patients and their families.

Check out:

• The Black Dog Institute - Resources including the Psychological Toolkit, Medical Observer articles, academic publications and research tools. The site also features education workshops, an online training program, webinars and the Being Well blog for health professionals.
• Kids Help Line - For kids aged 5-25 years. Information and access to phone chat, web chat and email chat. Phone - 1800 55 1800.
• Headspace - Information, services and link to e-headspace. It also has information for health professionals.
• e-headspace - For 16-25 year olds. Phone and online chats, online discussion groups with live information sessions.
• Reach Out - For 16-25 year olds. Information and a peer moderated forum.
• Bite Back - For 12-25 year olds. Information and interaction sessions based on positive psychology.
• The Butterfly Foundation - Information for people on eating disorders and body image issues, access to phone counselling.
• CanTeen - Support for 12-24 year olds struggling with a cancer diagnosis. Information, peer support groups and access to counselling.
• MoodGYM - Cognitive Behaviour Therapy-based (CBT) program for building resilience in people aged 16 and over.
• MyCompass - The Black Dog Institute site features psychological treatment-based modules for mild to moderate mental health conditions in young people aged 16 and over.
• MindSpot Clinic Mood Mechanic Program - The online wellbeing course is for 18-25 year olds and features virtual clinical structure as well as regular contact with counsellor by phone or email.
• BRAVE - Two separate CBT-based anxiety treatment programs for 8-12 year olds and 12-17 year olds.
• OCD! Not me - OCD treatment program for 12-18 year olds, with parent and family support.
• Smiling Mind App - Smart phone-based mindfulness training exercises for those aged seven years and above.
• This Way Up - Online courses for people with anxiety and depression. Developed by St Vincent’s Hospital, Sydney, it also features free CBT training courses for clinicians.
• Lifeline Australia - Crisis support and suicide prevention. Phone 13 11 14.
• Beyondblue - Information, support and advice, as well as clinical practice guidelines. Phone 1300 22 4636.
• Suicide Call Back Service - Free phone, video and online counselling. Phone 1300 659 467.