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Symptoms of mental illness

2-minute read

Each type of mental illness has a different set of symptoms. For example, extreme dieting may be a sign that someone has an eating disorder. Hearing voices could be a sign of psychosis. An ongoing feeling of hopelessness after childbirth could be a sign of postnatal depression.

Drastic changes in a person’s thoughts, moods or behaviour can be a sign they have a mental illness. Changes can be sudden or come on gradually over a long period. A person who usually copes well with life may start to have trouble functioning at work or in normal activities due to a mental illness.

Here are some examples of the symptoms of mental illness:

  • anxiety: excessive worry or fears
  • depression: persistent sad or low mood
  • unusual or illogical thoughts
  • unreasonable anger or irritability
  • poor concentration and memory, not being able to follow a conversation
  • hearing voices which no one else can perceive
  • increased or decreased sleep
  • increased or low appetite
  • lack of motivation
  • withdrawing from people
  • drug use
  • feelings that life is not worth living or more seriously suicidal thoughts
  • becoming obsessed with a topic, like death or religion
  • not looking after personal hygiene or other responsibilities
  • not performing as well at school or work

The symptoms of mental illness can come and go throughout a person’s life. Refer to the specific topics on this site for more detailed information.

Not sure what to do next?

If you or someone you know are finding it difficult to manage mental health issues, try healthdirect’s Symptom Checker and get advice on when to seek professional help.

The Symptom Checker guides you to the next appropriate healthcare steps, whether it’s self-care, talking to a health professional, going to a hospital or calling triple zero (000).

Last reviewed: November 2018

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