schizophrenia

• what is schizophrenia?


  a serious mental disorder characterised by a profound disruption of cognition & emotion.

  affects around 1% of the population
• what are the two types of symptoms of schizophrenia?

  positive & negative
• positive symptoms of schizophrenia

  delusions - bizarre beliefs - make sense to them but seem bizarre to others - 2 types:

  • delusions of persecution (the belief of being watched/followed)

  • delusions of grandeur (belief of being in a prominent position with power over others or have special powers)

  hallucinations - bizarre, unreal perceptions of the environment e.g auditory (hearing voices), visual (seeing things others can’t), olfactory (smelling things), tactile (feeling bugs crawling on you)

  disorganised thinking & speech - problem organising thought processes
• negative symptoms of schizophrenia

  • poverty of speech (alogia) - reduction in the amount & quality of speech

  • avolition - reduction in interests & desires as well as an inability to initiate & persist in goal-directed behaviour
• issues with validity of classification & diagnosis

  • gender bias - diagnostic criteria may be biased toward one gender rather than the other - clinicians may base judgements on stereotypical beliefs

  • symptom overlap - some symptoms of sz found in other disorders e.g both sz & bipolar have delusions - makes diagnosing difficult

  • comorbidity - the extent to which 2 or more conditions co-occur e.g people with sz also have symptoms of depression - makes treatments difficult
• evaluation of issues of validity

  • evidence for gender bias - randomly selected male & female psychiatrists given a case described as ‘male’, 56% gave a diagnosis of sz & when described as ‘female’ only 20% diagnosed - diagnosis subjective

  • evidence for symptom overlap - disorder DID have more symptoms of sz than some people diagnosed with sz - brings into question whether they are different disorders at all or all part of same spectrum
• issues with reliability of classification & diagnosis

  • culture bias - when psychiatrists are influenced by their own cultures values & expectations when diagnosing patients
• evaluation of issues of reliability

  • evidence for cultural bias - british & american psychiatrists given a description of a patient & asked for a diagnosis, 69% of americans diagnosed sz but only 2% of british did

  • major consequence of unreliable diagnosis relates to social stigma - inaccurate diagnosis can have long-lasting negative impact on the lives of those diagnosed
• what are biological explanations of schizophrenia?

  genetic & neural
• genetic explanation


  • sz is passed on from one generation to the next through genetic inheritance

  • the more closely related the family member is to the schizophrenic the greater their chances at developing sz

  • polygenic

  • evidence from family, twin & adoption studies

  • monozygotic twins should have higher concordance rates than dizygotic if it is genetic
• evaluation of genetic explanation

  • supporting evidence from family studies - found 16% of first degree relatives of schizophrenics developed sz compared to only 7% of control group - however could be due to environmental influence

  • support from twin studies - concordance rate of 40% for mz twins compared to 7% for dz twins - however not 100%
• neural explanation


  • mental illness is correlated with abnormalities in brain

  • enlarged ventricles = damage to central brain areas

  • dopamine hypothesis - positive symptoms a result of overactive transmission of the neurotransmitter dopamine - schizophrenics have abnormally high numbers of D2 receptors on receiving neurons so receive more dopamine - disturbances lead to problems with attention, perception & thought

  • revised dopamine hypothesis - positive symptoms caused by dopamine excess in mesolimbic pathway, negative caused by dopamine deficit in mesocortical pathway
• evaluation of dopamine hypothesis

  • practical applications - typical antipsychotics used to treat schizophrenia a block D2 receptors to reduce transmission of dopamine - reduces positive symptoms

  • however new drugs (atypicals) act on serotonin receptors as well as dopamine & shown to be more effective than typical - suggests hypothesis too simplistic

  • neural correlates have issues with cause & effect - brain abnormalities could be the effect rather than cause of sz e.g symptoms could cause changes in brain function

  • determinist

  • more humane
• family dysfunction explanations


  • double bind - children who receive contradictory messages from their parents are more likely to develop sz - regularly feels trapped in situations where they fear doing the wrong thing - reflected in symptoms like paranoid delusions

  • expressed emotion - the level of emotion expressed towards a sz sufferer by their family e.g verbal criticism, hostility, emotional over-involvement - increases likelihood of relapse
• evaluation of family dysfunction

  • evidence to support double bind - schizophrenics reported higher recall of double bind statements from their mothers than non-schizophrenics

  • support for expressed emotion - assessed adopted children whos bio mother had sz compared to control group of adoptees with no genetic risk - when parenting style of adoptive family was highlight critical with low empathy this increased risk of sz

  • practical applications - developed family therapy to increase recovery & decrease relapse - relapse rate in family therapy 26% compared to 50% in control group
• cognitive explanations for schizophrenia

  • symptoms a result of dysfunctional thought processing

  • egocentric bias - causes people to rely too heavily on their own point of view - underestimate how different other peoples views are or ignore them completely - believe external events have personal significance to them or are their fault

  • central control - the ability to suppress or override automatic thoughts, actions & speech in response to stimuli e.g feeling an urge to push a button - sz patients not able to suppress this urge
• evaluation of cognitive explanations

  • practical applications - development of CBTp - more effective than drug therapy in reducing symptom severity

  • reductionist - fail to take into account biological factors - need a more holistic approach

  • less determinist than biological explanations - have some element of control over thoughts & behaviours - however blames patient
• typical antipsychotics


  e.g chlorpromazine

  • dopamine antagonists - bind to dopamine receptors blocking their action - reduces positive symptoms
• atypical antipsychotics


  e.g clozapine

  • treat both positive and negative symptoms

  • temporarily block dopamine receptors

  • impact serotonin

  • have a lower risk of side effects, affect negative symptoms & treat treatment-resistant patients
• evaluation of drug therapies

  • support placebo research - chlorpromazine reduced symptoms & relapse rates compared to control group

  • criticism of typical - side effects - 30% develop tardive dyskinesia

  • revolving door syndrome - 50% patients stop taking medication after a year, 75% after 2 - leads to relapse & being given more drugs & stop taking them on release

  • side effects lower for atypical - rates of tardive dyskinesia much lower at just 5% - more appropriate than typical

  • support for atypical - more effective than typical - effective in 30-50% of treatment-resistant cases
• what are the 2 psychological therapies for schizophrenia

  CBT & family therapy
• CBTp


  • between 5 and 20 sessions

  • activating event leads to a belief that has a consequence

  • dispute the irrational beliefs & help patient to consider more rational ones

  • leads to an effect of feeling less anxious
• evaluation of CBT


  • supporting evidence - CBT far more effective than drugs in reducing symptom severity

  • however may be overstated - most studies conducted with patients also on antipsychotics - difficult to assess the effectiveness of CBT independently
• family therapy 


  • main aim is to reduce risk of relapse

  • educate families about risks of expressed emotion - enable them to reduce expressions of anger & guilt

  • taught about warning signs to help prevent relapse
• evaluation of family therapy

  • support - relapse rate in family therapy condition 26% compared to 50% in control group

  • more idiographic - can be easily adapted to the needs of individual patients/families unlike biological therapies that treat everyone the same way

  • only address symptoms & not cause - argued that sz has a biological cause so therapies like family therapy only addressing the symptoms rather than underlying cause
• token economy 


  • behavioural therapy

  • set target behaviours

  • based on idea of operant conditioning
• evaluation of token economies

  • support - meta-analysis of 13 studies found 11 had reported beneficial effects

  • may only be useful in institutions - may work because the environment is carefully structured so good behaviour can be consistently rewarded - patients may find difficult to transfer what they learned to everyday life

  • ethical concerns - viewed as taking power away from individual therefore has potential for abuse - can be abusive & humiliating
• interactionist approach 


  • diathesis-stress

  • interaction between nature & nurture

  • diathesis - genes play a key role - however 50% of mz twins when one has disorder the other doesn’t - suggests environmental factors

  • stress - stressful life events trigger schizophrenia- e.g childhood trauma 3x as likely - breakdown of a relationship, academic pressure etc

  • treatment - combination of antipsychotics & psychological therapies
• evaluation of diathesis stress

  • support from tienari - assessed adopted children who’s bio mother had sz - parenting style with high criticism aided development of sz but only those with high genetic risk - suggest both genetic vulnerability & stress are important

  • diathesis not exclusively genetic - may also result from brain damage - risk of sz for those who experienced birth complications was 4x greater

  • stress not exclusively environmental - illness & drug use may also trigger - cannabis seen as key stressor & increases risk up to 7x