Mental health diagnosis

 Understanding mental illness
 Diagnosing mental illness
 Dual diagnosis
 Classes of mental illness
 Helpful links

Understanding mental illness

Mental illness affects all of us in some way. 1 in 5 people experience a mental health concern each year. Almost half of the world’s population will experience a mental illness - you are not alone.

Mental illness is characterised by a disruption in a person’s thoughts, feelings or moods to a level that interferes with daily functioning and relationships.

Most treatments and supports for mental illness are delivered in the community, often allowing people to remain at home. If hospitalisation is required, it is usually only for a short stay. Community awareness about mental illness is increasing, stigma is declining and help is available.

Diagnosing mental illness can take time, but taking the time and going through a process will help you get an accurate diagnosis and allow appropriate treatment.

It is important remember that your diagnosis does not define you.

Diagnosing mental illness

  • See your General Practitioner (GP) and request a physical examination to rule out physical problems that may be responsible or parctically responsible, for your symptoms. (You should request an extended consultation with your GP when you start this process)
  • Discuss the range of symptoms, thoughts and behaviours you are experiencing; especially those that trouble you or are new and unusual. (It may take multiple visits before you have a diagnosis and a plan of treatment.)
  • Ask your doctor to explain your illness or disorder and discuss what treatments are available.

Dual diagnosis

Dual diagnosis means someone is suffering a mental illness and a substance use problem. People who abuse alcohol, illegal drugs, prescription medication and even tobacco often have a higher rate of having mental health issues.

Comorbidity or Co-Occurrence

Comorbidity or co-occurrence is a term used to describe when there is more than one health condition present.  This can be mental or physical.  For example someone may be diagnosed with bipolar disorder with comorbidity borderline personality, or perhaps schizophrenia with co-occurrence diabetes.

Classes of mental illness

The main classes of mental illness are (These are man of the main disorder, but not a fully conclusive list.)

It is not unusual for an individual to suffer more than one mental health condition.

  • Anxiety disorders. Anxiety is an emotion characterized by the anticipation of future danger or misfortune, accompanied by feeling ill at ease. This class includes generalized anxiety disorder, panic disorder and phobias.
  • Bipolar, bipolar rapid cycling and related disorders. This class includes disorders with alternating episodes of mania (periods of excessive activity, energy and excitement) and depression.  
  • Depressive disorders. These include disorders that affect how you feel emotionally, typically levels of sadness. Examples include major depressive disorder and premenstrual dysphoric disorder, pre and post-natal depression.
  • Dissociative disorders. These are disorders in which your sense of self is disrupted, such as with dissociative otherwise unspecified, dissociative identity disorder and dissociative amnesia.
  • Disruptive, impulse-control and conduct disorders. These disorders include problems with emotional and behavioural self-control.
  • Eating disorders. These disorders include disturbances related to eating, such as anorexia nervosa, bulimia and binge-eating disorder.
  • Elimination disorders. These disorders relate to the inappropriate elimination of urine or stool by accident or on purpose. Bedwetting is an example. (This does not include every young child who has not yet learned to control their elimination system.)
  • Gender dysphoria. This refers to the distress that accompanies a person's desire to be another gender.
  • Neurocognitive disorders. Neurocognitive disorders affect your ability to think and reason. This includes delirium, as well as neurocognitive disorders due to conditions or diseases such as traumatic brain injury or Alzheimer's disease.
  • Neurodevelopmental disorders. Covers a wide range of problems that usually begin in infancy, childhood or the teenage years. Examples include autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD) and learning disorders.
  • Obsessive-compulsive and related disorders. These disorders involve preoccupations and obsessions, including repetitive thoughts and actions. Examples include obsessive-compulsive disorder, excessive counting, avoiding particular things or places, hoarding and hair-pulling disorder (trichotillomania).
  • Paraphilic disorders. Disorders including sexual interest that causes personal distress or impairment or causes potential or actual harm to another person. Examples are sexual sadism, voyeuristic disorder and paedophilic disorder.
  • Personality disorders. A personality disorder involves a lasting pattern of emotional instability and unhealthy behaviour that causes problems in an individual’s life and relationships. Examples include borderline personality disorder, histrionic personality disorder, narcissistic personality disorder and antisocial personality disorder.
  • Post-Traumatic Stress disorder. PTDS is an emotional response to a terrible event like an accident, rape or natural disaster. Immediately after the event, shock and denial are typical. Longer term reactions include unpredictable emotions, flashbacks, strained relationships and even physical symptoms like headaches or nausea. While these feelings are normal, some people have difficulty moving on with their lives. (American Psychological Association
  • Complex Trauma can occur when there is a history multiple traumatic events or abuse and/or when the events occur in the vital stages of childhood development. They can be prolonged, extreme, repeated, inescapable, and often done at the hands of the people that the individual relies for their safety, care and understanding of the world. 
  • Schizophrenia spectrum and other psychotic disorders. Psychotic disorders cause detachment from reality (delusions, paranoia and hallucinations).
  • Sleep-wake disorders. Sleep disorders that are severe enough to require clinical attention, such as insomnia, sleep apnoea and restless legs syndrome.
  • Substance-related and addictive disorders. Disorders associated with addiction to alcohol, caffeine, tobacco, drugs, gambling, sex or others.

Helpful links

Reach Out



Early Psychosis Prevention and Intervention Centre

Mental Health Fellowship
Sane Australia 1800 187 263

Bipolar Caregivers

Beyond Blue
Better Health Channel

Borderline Personality Disorder Community 0409 952 754
Mindhealthconnect 1300 286 463
MIND Victoria
Anxiety Disorders Association of Victoria Inc.  (03) 9853 8089
Mental Health Foundation of Australia VMIAC (03) 9830 3900

National Institute of Mental Health
Post and Antenatal Depression Association PaNDa 1300 726 306

Schizophrenia Fellowship of Australia (03) 9368 0600
Spectrum The Personality Disorder Service for Victoria (03) 8833 3050

Voices Vic (community mental health support and information for people who hear voices others do not hear) (03) 9692 9500