Diagnosis

• Schizophrenia has no defining features. It is a cluster of seemingly unrelated symptoms.
• Schizophrenia is a psychosis, which is a collection of symptoms that affect the mind, where there has been some loss of contact with reality.
• Schizophrenia is more commonly diagnosed in men than women and seems to affect the working class more than the middle class.
• Negative symptoms of schizophrenia are a loss of something from the neurotypical experience.
• Negative symptoms include Avolition where the person begins to struggle with goal directed behaviour. Andreason suggested this involves; poor hygiene, lack of work persistence and lack of energy
• Another negative symptom is Speech poverty, which is a reduction in the amount or quality of speech. This can include missing words.
• A positive symptom of schizophrenia is the addition of something to the neurotypical experience.
• A positive symptom of schizophrenia is hallucinations which refer to unusual sensory experiences that can be picked up from any sense (but is usually auditory such as hearing voices).
• A positive symptom Of schizophrenia is delusions which refer to irrational beliefs and come in a variety of forms (eg paranoia, grandeur, external control).
• A positive symptom of schizophrenia is speech disorganisation in which speech becomes incoherent or the speaker changes topic mid-sentence. This is usually related to thought insertion.
• The DSM-V is the American psychiatric association's diagnostic and statistical manual edition 5. It suggests that one or more postive symptoms must be present to recieve a diagnosis - cannot be caused by drugs.
• THe ICD-10 is the world health organisations internal classification of disease edition 10. This requires two or more negative symptoms to be diagnosedd and also recognises different types of schizophrenia, eg paranoid + catatonic.
• A good diagnostic tool needs to be reliable and valid

  • Reliablity: Consistancy/Repeatable
  • Validity: Legitimacy
• Cultural Differences could effect reliablity and validity of diagnosis as the different values, beliefs and practices that exist between cultures may have an effect.
• Gender Bias - The tendency to describe the behaviour of men and women in psychological theory and research in such a way that may not accurately represent the characteristics of either gender. This could lead to the over of under-diagnosis of schizophrenia for either gender.
• Symptom overlap - Occurs when two or more conditions share symptoms. Where conditions share many symptoms. This calls into question the validity of classifying the two disorders separately.
• Comorbity - Simultaneous presence of two or more diseases or medical conditions in a patient. This makes it difficult for healthcare professionals to diagnose schizophrenia as a distinct mental illness.
• Strength Diagnosis - Good Reliablity

  • More recent research suggests that there is good inter-rater reliability. Osorio et al found that most diagnosis were +0.97 reliable.
• Limitation Diagnosis - Issue of Validity

  • Cheniaux (2009) found that of 100 clients assessed, 68 recieved a diagnosis of schizophrenia using the ICD-10 and 39 using DSM-IV, showing low criterion.
  • Inter-rater reliability was very poor as it is quite subjective.
• Limitation Diagnosis - Symptom Overlap

  • There is considerable overlap between the symptoms of schizophrenia and other conditions. For example, both schizophrenia and bipolar have delusions and avolition, which calls in question the validity of both the classification and diagnosis of schizophrenia.
• Limitation Diagnosis - Comorbidity

  • Around half of patient also have another diagnosis e.g. substance abuse and depression. This calls into question the existance of schizophrenia as a distinct condition.
  • Backley et al found that around half of patients that have schizophrenia have another condition.