Healthy individuals differ significantly in their overall personality, mood, and behaviour.

Each individual also varies from day to day, depending on the circumstances.

However, a sudden, major change in personality and/or behaviour, particularly one that is not related to an obvious event (such as taking a drug or losing a loved one), often indicates a problem (see Overview of Mental Illness).

Changes in personality and behaviour can be roughly categorised as one of the following:

  • Confusion or delirium;
  • Delusions;
  • Disorganised speech or behaviour;
  • Hallucinations; and
  • Mood extremes (such as depression).

These categories are not disorders. They are just one way medical professionals organise different types of abnormal thought, speech, and behaviour. These changes in personality and behaviour can be caused by physical or mental health problems.

Individuals may have more than one type of change. For example, individuals with confusion due to a drug interaction sometimes have hallucinations, and individuals with mood extremes may have delusions.

General Symptoms

The signs and symptoms of mental illness can vary, depending on the disorder, circumstances, the individual and other factors.

Mental illness symptoms can affect emotions, thoughts and behaviours.

Examples of signs and symptoms include:

  • Feeling sad or down.
  • Confused thinking or reduced ability to concentrate.
  • Excessive fears or worries, or extreme feelings of guilt.
  • Extreme mood changes of highs and lows.
  • Withdrawal from friends and activities.
  • Significant tiredness, low energy or problems sleeping.
  • Detachment from reality (delusions), paranoia or hallucinations.
  • Inability to cope with daily problems or stress.
  • Trouble understanding and relating to situations and to people.
  • Problems with alcohol or drug use.
  • Major changes in eating habits.
  • Sex drive changes.
  • Excessive anger, hostility or violence.
  • Suicidal thinking.

Sometimes symptoms of a mental health disorder appear as physical problems, such as stomach pain, back pain, headaches, or other unexplained aches and pains.

When to Seek Help

If you have any signs or symptoms of a mental illness, see your medical/mental health professional.

Most mental illnesses do not improve on their own and, if untreated, a mental illness may get worse over time and cause serious problems.

If you have Suicidal Thoughts

Suicidal thoughts and behaviour are common with some mental illnesses.

If you think you may hurt yourself or attempt suicide, get help right away.

Helping a Loved One or Friend

If your loved one/friend shows signs of mental illness, have an open and honest discussion with them about your concerns.

You may not be able to force someone to get professional care, but you can offer encouragement and support.

You can also help your loved/friend one find a qualified medical/mental health professional and make an appointment.

You may even be able to go along to the appointment.

If your loved one/friend has done self-harm or is considering doing so, take them to the hospital or call for emergency help.