General public definition
- Mental illness refers to emotions, behaviours, and difficulties in thinking that affect a person’s ability to clearly understand the real world and what is happening to them and around them. These emotions, behaviours, and difficulties are generally the signs and symptoms of the mental illness.
- The signs and symptoms of a mental illness can range from mild to severe.
- These signs and symptoms can usually be diagnosed as a particular kind of mental illness, as outlined in the DSM-5-TR or the ICD 11.
- Mental illness is often accompanied by distress and decreased functioning in social, occupational, or other activities of daily life.
Academic definition
- Mental illness refers to mental disorders, diagnosed or as yet undiagnosed.
- Mental illness ranges in severity from mild to severe.
- Mental illness is associated with significant distress in social, occupational, or other activities of daily living.
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