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Definition of Schizophrenia

  • mental illness which affects how brain work

  • chronic problems with abnormal thoughts, behaviour

  • certain symptoms are experienced for at least a year, e.g hallucinations

  • affects ~0.3%-0.7% of people, more common in men

  • require lifelong care and treatment


1. Family history and genetics

1.1 Family connections

  • greatly affect the risk of having schizophrenia

  • e.g if an identical twins has schizophrenia, the kids will have 50% of chances to having the same illness; if both parents have schizophrenia, you have 40% of chances of developing it

  • affect by genetics but not family environment

  • children have high chances of given up for adoption→ parents can’t take care of them anymore

  • only genes won’t cause schizophrenia

2. Environmental factors

2.1 Viral infections

  • exposure to virus

  • possible traits of a virus: e.g attacking certain brain areas, infecting someone and staying in the body for many years, causing abnormal but minor physical problems, and affects neurotransmitters

2.2 Herpes viruses

  • may be caused by 2 herpes viruses: HSV (herpes simplex virus), CMV (cytomegalovirus)

2.3 Other infectious influences

  • having toxoplasmosis gondii antibodies (protozoan parasite carried by cats)

  • data shows a person who is raised around cats is more likely to develop schizophrenia

2.4 Exposure to toxins

  • being exposed to harmful toxins, even during the early period of schizophrenia’s development

  • toxins show possible influence (alcohol and lead)

2.5 Lead

  • significant influence

  • can be found in gasoline, paint, tap water etc.

3. Societal factors

3.1 Live in a populated area

  • risk of having schizophrenia in urban areas is larger than rural areas

3.2 Prenatal exposure to hunger

  • famine during pregnancy means that children have a high risk of developing schizophrenia

3.3 Family environment

  • increase stress and chances of being abused by parents/people in the family who have schizophrenia

  • may develop schizophrenia themselves

  • people who have schizophrenia may not have trauma from their past - they could have had a loving and caring family

  • therefore people often blame the parents for the children’s illnesses

4. Brain and body risk factors

4.1 Early disruptions

  • complicated process

  • neurogical events

  • abnormalities

  • e.g more common for the children who are born in spring or winter, birth complications and famine increase the risk for the children to have schizophrenia

  • not enough evidence to prove that developmental theories make schizophrenia disorganized

4.2 Neurochemicals

  • involve irregularities in chemicals of the brain

  • neurotransmitters with drugs (amphetamine and PCP)

  • dopamine inbalance

  • abnormalities in the neurotransmitters GABA and glutamate

5 Lifestyle factors

5.1 Stress

  • physiological effects that cause psychiatric disorder, e.g post-traumatic stress disorder

  • cause high-blood pressure, heart disease etc.

  • traumas, e.g wars, natural disasters, imprisonment, sexual abuse

  • psychogical stress

5.2 Life-changing events

  • loss, e.g family member’s death, jobs etc.

  • cause suicide, withdrawal, loss of motivation


Psychosis: abnormal state which high functions of mind are disruptedPositive symptoms: only present in someone who has schizophreniaNegative symptoms: disappearing traits from the person who has schizophreniaCognitive symptoms: the way the person thinkspsychotic disorderHallucinations:

  • false sensory experiences

  • not caused by drugs or alcohol

  • auditory and visual hallucinations are the most common

  • hearing voices, sounds, seeing patterns, objects that are not real, feeling sensations

Flattened affect:

  • emotionless

  • no reactions to situations

  • no facial expressions, hand gestures at all

Difficulty maintaining attention:

  • easily ‘spaces out’ when listening to others

  • unable to focus on someone

emotions and beliefs become disorganized and away from realityDelusions:

  • fixed, false, distorted belief

  • doesn’t make sense

  • strongly believe their own belief, so convinced that no one can change their mind


  • lack of joy

  • nothing can bring them happiness

  • lack of positive emotions

Difficulty planning and structuring activities:

  • caused by reduced executive function

  • disorganized work

  • unable to identify a step in a task

Disorganized speech:

  • impossible to understand to most people

  • not speech error but a bunch of words that is difficult to interpret

Reduced speech:

  • speak less than usual

  • less fluent when speaking

Memory problems:

  • unable to remember things, e.g birth date, address etc.

Disorganized behaviour:

  • unsensible and unreasonable behaviour

  • e.g taking clothes off in public, shouting at random people in the street

Lack of initiative:

  • losing motiviation

  • no plans to do anything

Lack of insight:

  • have specific cognitive blind spot that makes them oblivious to the fact that they have schizophrenia


Researcher: Karina


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