Signs of mental illness

The World Health Organisation describes good mental health as: 'a state of wellbeing in which the individual realises his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution  to his or her community'.

What is mental illness?

Mental illness is a general term that refers to a group of illnesses affecting the mind, in the same way that physical illness affects the body.

A mental illness is a clinically diagnosable illness that affects a person's thinking, emotional state or social abilities. It may disrupt their ability to work, carry out daily activities or have satisfying personal relationships.

Just as all people are different, so too are the types of mental illness and their impact. Some people may require support for a short amount of time whereas others may need life-long support.

Often people experience mental illness for a long time before finding help.

About 1 in 5 Australians will experience a mental illness in any given year, and almost half will experience a mental health problem at some point in their lives.

What causes mental illness?

There are a number of factors that can contribute to a mental illness, such as:

  • a chemical imbalance in the brain
  • stressful life events
  • drug use.

Common mental illnesses and disorders


It is important to understand the difference between the normal feelings of unhappiness or sadness which all of us experience at various stages of life and the symptoms of clinical depression.

  • Clinical depression is a state of extreme distress where the sufferer feels empty or numb rather than just sad.
  • A depressed person is unable to enjoy life normally or break out of the depressed state.
  • A persistent depressed mood may be considered a disorder when it is present all or most of the time, for at least 2 weeks.
  • In a major depressive episode, someone might also experience:
    • diminished appetite with weight loss
    • increased appetite with weight gain
    • insomnia or increased sleep
    • agitation or slowed movements
    • loss of all pleasure and enjoyment
    • tiredness and fatigue
    • feelings of guilt and worthlessness
    • poor concentration
    • thoughts of death, including suicidal thoughts and plans.
  • Suicidal thoughts are never normal, and indicate a need for urgent help.
  • For more information about depression, visit:

Postnatal depression (PND)

  • It is common for women to experience increased emotions or feelings of being overwhelmed during the weeks after giving birth.
  • When emotional distress is constant and disabling it can reach the level of clinical depression. Postnatal depression (PND) is the name given to depression that develops between 1 month and up to 1 year after the birth of a baby.
  • PND can be a devastating and debilitating illness that affects not just a new mother but everyone around her, and in particular her relationship (or attachment) with her new baby.
  • PND can be mild, moderate or severe and symptoms can begin suddenly after birth or appear gradually in the weeks or months during the first year after birth.
  • Postnatal depression affects almost 16% of women giving birth in Australia.
  • For more information about PND, visit beyondblue

Anxiety and anxiety disorder

  • Anxiety is a term which describes the feeling you experience when faced with threat, danger or stress.
  • When you become anxious, you typically feel upset, uncomfortable and tense.
  • It can be caused by life experiences, such as job loss, relationship breakdown, serious illness, a major accident or the death of someone close.
  • Feeling anxious is normal in these situations but usually only lasts for a limited time. These feelings are not regarded as clinical anxiety, but are a part of everyday life.
  • For some people these feelings are ongoing, happen for no apparent reason, or continue after the stressful event has passed.
  • An anxiety disorder can occur in a person when their level of anxiety and feelings of panic are so extreme that it significantly interferes with their daily life.
  • For more information about anxiety disorders visit:

Bipolar disorder

  • Signs of bipolar disorder are episodes of unusual highs or irritable mood (mania or hypomania) possibly mixed with depressive episodes.
  • It is also known as bipolar mood disorder, bipolar affective disorder and previously as manic-depression.
  • People with bipolar disorder may experience psychotic symptoms such as hearing voices or delusions, which are typically in keeping with their current mood state, for example:
    • in a depressive episode, the sufferer may believe they have significant physical health problems, reasons to be guilty, or that they are poverty-stricken.
    • in a manic episode, they might think they have great wealth, special powers or a special mission.
  • Some people with bipolar disorder do not experience depressive episodes, only the episodes of elation and excitement.
  • For more information about bipolar disorder, visit:


  • Schizophrenia affects the normal brain function, interfering with a person’s ability to think, feel and act, and is characterised by psychotic symptoms.
  • It usually presents itself for the first time during adolescence or early adulthood. It can develop in older people, but this is not as common.
  • Some people may experience only 1 or more brief episodes in their lives. For others, it may remain a recurrent or life-long condition.
  • Schizophrenia can be diagnosed when at least 2 different types of psychotic symptoms persist for a month, and some degree of symptoms continue for at least 6 months.
  • Symptoms may include:
    • delusions—a false belief held by a person which is not held by others of the same cultural background
    • hallucinations—a person sees, hears, feels, smells or tastes something that is not actually there
    • disorganised thought, speech or behaviour
    • diminished emotional expression
    • decreased motivation.
  • For more information about schizophrenia, visit Sane Australia


  • Psychosis is a group of symptoms seen in a number of different illnesses including:
    • schizophrenia
    • schizoaffective disorder
    • delusional disorder
    • brief reactive psychosis
    • bipolar disorder
    • psychotic depression
  • It can also be as a result of the effects of illicit substances or some physical illnesses.
  • Symptoms can include:
    • delusions—false beliefs that are utterly true to the person who is experiencing the psychosis, but not understandable to others.
    • hallucinations—sensory experiences which seem entirely real to the person experiencing them, but are unable to be shared by others (e.g. hearing 'voices').
    • disorganised thought, speech or behaviour.
  • These symptoms may lead to social withdrawal and reduced performance at school, university or work.
  • Most people are able to recover from an episode of psychosis.
  • For more information about psychosis, visit Sane Australia

Where to get help

Find community support for mental illness—help line numbers, counselling and support groups for you or someone you know.