
Mental illnesses rarely appear out of the blue. Most often family, friends, teachers, or individuals themselves recognise that something is not quite right about the way they are thinking, feeling, or behaving which suggest it is a good idea to see a doctor for an assessment and get help if needed. Getting treatment and support early can lead to an intervention that can help reduce the severity of an illness. It may even be possible to prevent the mental illness from having such a serious impact.
Here are some signs and symptoms often associated with mental illness or psychological distress. It is important to only use these as a guide not a method of diagnosis. This can only be done by a doctor or other suitably-qualified health professional. These checklists provide a basis to have a conversation with the person you are worried about.
Having one or two of these symptoms doesn’t necessarily indicate a mental illness. However, a person experiencing several of these symptoms together, causing serious problems in his or her ability to study, work, or relate to others, should see a mental health professional for an assessment in order to get help.
Behaviour that is considered normal although difficult
People may be:
- rude
- irritable
- over-sensitive
- lazy
- argumentative
- weepy
- over-emotional
- withdrawn
- thoughtless.
These behaviours may also occur as a normal brief reaction to stressful events such as:
- breakup of close relationship
- other family crisis
- exam failure
- moving house
- death of a loved one
- physical illness
- divorce
- other personal crisis.
In these cases, the person probably does not need to see a doctor for assessment. Try not to over-react, and be as supportive as possible while waiting for the bad patch to pass. If the behaviour is disruptive or distressing for other people, or if the difficult behaviour persists, seek help from a counsellor, GP or other health worker.
Behaviours that are concerning
- withdrawing completely from family, friends and others
- sleeping poorly – for example, sleeping during the day and staying awake all night
- becoming very preoccupied with a particular topic – for example, death, politics or religion
- uncharacteristically neglecting responsibilities, personal hygiene or appearance; eating poorly
- deteriorating in performance at school or work
- having difficulty concentrating, following conversation or remembering things
- panicking, becoming anxious, depressed, or talking about suicide
- having extreme changes in mood for no real reason
- hearing voices that no-one else can hear
- believing, without reason, that others are plotting against or spying on them, and feeling fearful or angry about this
- believing they are being harmed, or influenced to do things against their will – for example, by television, the internet, aliens or the devil
- believing they have special powers or influence when this is not so
- believing their thoughts are being interfered with, or that they can influence the thoughts of others.
- spending extravagant and unrealistic sums of money.
These behaviours are much stronger signs that something needs to be checked out by a doctor as soon as possible, particularly if they have been present for some weeks. There may only be a minor disturbance but a mental illness, such as a psychotic disorder, may be developing.
If several of the following are occurring, a serious condition may be developing.
- recent social withdrawal and loss of interest in others
- an unusual drop in functioning, especially at school or work, such as quitting sports, failing in school, or difficulty performing familiar tasks
- problems with concentration, memory, or logical thought and speech that are hard to explain
- heightened sensitivity to sights, sounds, smells or touch; avoidance of over-stimulating situations
- loss of initiative or desire to participate in any activity; apathy
- a vague feeling of being disconnected from oneself or one’s surroundings; a sense of unreality
- unusual or exaggerated beliefs about personal powers to understand meanings or influence events; illogical or ‘magical’ thinking, typical of childhood but not in an adult
- fear or suspiciousness of others or a strong nervous feeling
- uncharacteristic, peculiar behaviour
- dramatic sleep and appetite changes or deterioration in personal hygiene
- rapid or dramatic shifts in feelings or ‘mood swings.’
One or two of these symptoms doesn’t necessarily indicate a mental illness. But a person experiencing several together that are causing serious problems in his or her ability to study, work, or relate to others should be seen by a mental health professional.

What about drugs?
Drugs such as cannabis can also produce psychotic symptoms like those listed in the second checklist above. This may be short-term (a drug-induced psychosis) or can lead to a long-term psychotic illness such as Schizophrenia. If someone’s behaviour worries you – or drug use causes problems at home, school or work – then try to get help for the person. A doctor can make a medical assessment to see if there is a mental illness which needs treatment, or decide if referral to a drug and alcohol agency for treatment would help.
To discuss any of these symptoms you may have noticed in someone you know, the SANE Help Centre can help provide some clarity and options for moving forward.