Types, Causes and  Symptoms of Depression:

It’s normal to feel sad or down from time to time. Sometimes, though, these feelings can be more intense or last longer than usual. When this happens, it may be a sign of depression, which can affect both physical and mental wellbeing. Depression can take different forms, and the approach to management may vary.

This webpage is intended to provide general information about depression, including research on possible contributing factors such as lifestyle and nutrition. Psychologists at this clinic focus on psychological support as part of a broader, evidence-based approach to mental health. They do not provide specific advice on diet or nutrition, but may suggest seeing a dietitian or nutritionist if this could be helpful for you.

Depression isn’t just one thing. It comes in different forms, and the symptoms can range from mild to very disabling. Knowing the various types can help you understand what you or someone close to you might be experiencing.

Major Depression
This type involves a low mood that sticks around for at least two weeks and makes it hard to do everyday things. People may lose interest in activities, have trouble with sleep or appetite, feel tired, or experience thoughts of worthlessness.

Melancholic Depression
A more severe form of depression, melancholia includes a complete loss of pleasure in almost everything and noticeable slowing down of thoughts and movements.

Psychotic Depression
Sometimes, depression can come with symptoms like seeing or hearing things that aren’t there or holding beliefs that aren’t true. These experiences can make depression harder to treat and usually need a combination of supports.  Psychotic depression requires assessment and treatment by a psychiatrist.

Antenatal & Postnatal Depression
Depression can occur during pregnancy (antenatal) or after having a baby (postnatal). There’s some evidence that nutrition, including omega-3 levels, might play a role.

Bipolar Depression
Bipolar disorder involves episodes of both depression and mania (periods of high energy and mood). It’s important to look for signs of both, as this helps with an accurate diagnosis.

Cyclothymic Disorder
This is a milder, long-lasting version of bipolar disorder, with mood swings that aren’t as extreme.

Dysthymia
Also called persistent depressive disorder, dysthymia features milder symptoms that last two years or more.

Seasonal Affective Disorder (SAD)
SAD is depression that’s linked to changes in seasons, most often starting in winter. Reduced sunlight can be a factor, and light therapy is sometimes used to help.

Causes of Depression

Depression can have many causes. It often happens when stress builds up beyond a person’s ability to cope, leading to feelings of hopelessness. Both ongoing life stress (like job loss or relationship difficulties) and sudden events can play a part, especially if someone has a family history or certain personality traits. Poor diet and environmental factors may also influence risk.

Signs and Symptoms

A diagnosis of depression generally requires ongoing low mood and loss of interest in things, plus other symptoms like sleep or appetite changes, low energy, trouble concentrating, or thoughts of worthlessness or suicide, lasting for at least two weeks.

Common Behaviours

• Withdrawing from friends and family
• Losing interest in usual activities
• Struggling to complete tasks at home, work, or school
• Using alcohol or drugs more than usual
• Difficulty concentrating

Common Feelings

• Overwhelmed
• Guilty
• Irritable or frustrated
• Lacking confidence
• Unhappy or sad
• Indecisive or disappointed

Common Thoughts

• “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

• Feeling tired all the time
• Headaches or muscle aches
• Upset stomach
• Trouble sleeping
• Changes in appetite or weight

If you or someone you know is struggling, support from a qualified health professional can help.

These services are confidential, free, and available to anyone in Melbourne or across Victoria. If you’re ever unsure, calling Triple Zero (000) is the fastest way to get urgent help.

Updated on:   21/02/2026 by: Dr. Jacques Duff – BA Psych; Grad Dip Psych; PhD; MAPS; MECNS; MAAAPB; MISNR; FANSA
Reviewed on: 24/02/2026 by: Bernard Ferriere - BA; Grad Dip App Psych; Dip Clinical Hypnosis; FCCP; MAPS; MASH; Clinical Psychologist