Overview Of Schizophrenia

Overview of schizophrenia Classification and diagnosis Nature of schizophrenia Profound disruption of cognition and emotion- affects language, perception, affect and sense of self. Association with violence is largely a media invention. Around 8% of patients diagnosed with schizophrenia commit a serious act of violence but this figure than for other mental disorders.

Diagnostic criteria Positive symptoms- excess or distortion of normal symptoms e.g. delusions (bizarre beliefs), experiences of control (e.g. by alien force), hallucinations (unreal perceptions), disordered thinking (e.g. thought insertion). Negative symptoms- diminution or loss of normal functions, e.g. affective flattening (reduction in emotional expression), alogia (poverty of speech), avolition (lack of goal- directed behaviour). Diagnosis of schizophrenia- (a) two or more characteristic symptoms, (b) social/occupation dysfunction, (c) duration (at least six months), (d) exclusion of mood disorders, (e) exclusion of organic cause.

Reliability Extent to which psyhiatrists can agree on the same diagnosis. DSM III and later versions claim increased reliability of diagnosis. Whaley (2001)- inter-rater reliability as low as .11. Klosterkotter et al. (1994)- positive symptoms more useful for diagnosis than negative symptoms. Mojtabi and Nicholson (1995)- low inter-rater reliability of `bizarre` versus `non-bizarre` symptoms. Problem highlighted in Rosenhan`s study `On being sane in insane places`.

Validity Concerns questions about what schizophrenia really is. First-rank symptoms distinguish schizophrenia from other disorders, but some of these are also found in other disorders such as DID. Little evidence of shared prognosis in schizophrenia, therefore low predictive validity.

Therapies for schizophrenia Biological therapies Antipsychotic medication Conventional antipsychotics reduce effects of dopamine and so reduce symptoms of schizophrenia. Bind to D2 dopamine receptors but do not stimulate them. Atypical antipsychotics only temporarily occupy D2 receptors then dissociate to allow normal dopamine transmission. Leads to lower levels of side effects such as tardive dyskinesia.

Commentary Davies et al. (1980)- higher relapse rate in patients whose drug replaced with placebo that those who remained on drugs. Antipsyhotic medication more effective for those living with hostility and criticism. Conventional antipsychotics- 30% develop tardive dyskinsia. Being prescribed medication creates motivational deficits which prevents positive action against illness. Meta-analysis (Leucht et al., 1999)- superiority of atypical over conventional antipsychotics only moderate. Atypical antipsychotics- only marginal support for effectiveness with negative symptoms. Lower rate of tardive dyskinesia with a typical antipsychotics supported by Jeste et al. 1999). Patients more likely to continue with medication if fewer side effects.

ECT First studies of ECT as treatment for schizophrenia were disappointing (Karagulla, 1950), with recovery lower than control group. Tharyan and Adams (2005)- review of 26 studies found `real` ECT more effective than `sham` ECT. Combination of medication and ECT effective for rapid reduction symptoms. Commentary Effectiveness of ECT is inconsistent. APA study found no difference between effects of ECT and antipsychotic medication. Sarita et al. (1998)- no difference in symptom reduction between ECT and simulated ECT. Because of risk of ECT (e.g. memory dysfunction, brain damage) use has declined.

Synoptic links Ross and Read (2004)- placebo studies not a fair test because proportion of relapses explained by withdrawal effects. Ethical issues- human right issues associated with use of antipsychotic medication (e.g. tardive dyskinesia).

Psychological therapies CBT Patients: 1) trace origins of symptoms to understand how they might have developed and 2) evaluate content of delusions/hallucinations. Patients allowed to develop own alternatives to maladaptive beliefs. Outcome studies show that patients receiving CBT experience fewer hallucinations and delusions than those receiving antipsychotic medication alone. Lower patient drop-out rates and greater patient satisfaction with CBT than antipsychotic medication. Commentary Effectiveness- meta-analysis found significant decrease in positive symptoms after CBT treatment. Most CBT studies involve antipsychotic medication, therefore difficult to assess effects of CBT alone. CBT works by generating less distressing explanations for psychotic experiences rather than trying to eliminate them. Psychiatrists believe that older patients are less likely to benefit from CBT.

Psychodynamic therapies Psychoanalysis based on assumption that individuals unaware of influence of unconscious conflicts on their current psychological state. Therapist creates an alliance with patient by offering help with what patient perceives as problem. All psychodynamic therapies build trust with patient by replacing harsh parental conscience with one that is more supportive. As patient gets healthier they take a more active role. Commentary Meta-analysis (Gottdiener, 2000)- 66% of those receiving psychotherapy improved after treatment, while 35% didn`t. Some forms of psychodynamic therapy can even be harmful in treatment of schizophrenia. Research on effectiveness of psychodynamic therapy shows contradictory findings. `Supportive` psychotherapies appropriate when combined with antipsychotic medication. Psychodynamic therapy long and expensive but may have benefits in that it might make patients more able to seek employment.

Synoptic links Methodological limitations of psychodynamic outcome studies include lack of random allocation to therapy conditions. Ethical issues arise in placebo condition where patients are denied effective treatment.

Explanations of schizophrenia Biological explanations Genetic factors Schizophrenia more common among biological relatives of person with schizophrenia (Gottesman, 1991). Twin studies- Joseph (2000) pooled data shows concordance rate of MZ twins and DZ twins at 7%. Use of `blind` diagnoses produces lower concordance rate for MZ twins, but still much higher than DZ. Adoption study by Tienari et al (2000)- if biological mother schizophrenic, 6.7% of adoptees also schizophrenic (2% of controls). Commentary Environments of MZ twins may be more similar than for DZ twins. Differences in concordance rates may reflect environmental similarity rather than role of genetic factors. Adopted children from schizophrenic backgrounds may be adopted by particular type of adoptive parent, making conclusions difficult to draw.

Dopamine hypothesis Neurons that transmit dopamine fire too easily or too often, leading to symptoms of schizophrenia. Schizophrenics- abnormally higher levels of D2 receptors. Evidence from large doses of amphetamines (dopamine agonist) causes hallucinations and delusions. Antipsychotic drugs- block dopamine and eliminate symptoms. Parkinson`s disease- treatment with L-dopa raises dopamine levels and can therefore also trigger schizophrenic symptoms. Commentary Drugs can increase schizophrenia symptoms as neurons try to compensate. Haracz (1982) found elevated dopamine levels in post-mortems of schizophrenics who had taken medication. Neuroimaging studies failed to provide convincing evidence for altered dopamine activity in schizophrenics.

Enlarged ventricles Ventricles of person with schizophrenia 15% bigger than non-schizophrenic. Display negative rather than positive symptoms. May be result of poor brain development or tissue damage.

Commentary Meta-analysis found substantial overlap in ventricle size among schizophrenic and control populations. Enlarged ventricles may be due to effects of antipsychotic medication.

Synoptic links Many studies have to include `schizophrenia spectrum disorders` to show genetic influences. Evolutionary perspective- schizophrenia may have adaptive advantages (e.g. group splitting hypothesis).

Psychological explanations Psychological theories Psychodynamic view of schizophrenia- result of regression to pre-ego stage and attempts to re-establish ego control. Some schizophrenic symptoms reflect infantile state, other symptoms are an attempt to re-establish control. Further features of disorder appear as individuals attempt to understand their experiences. They may reject feedback from others and develop delusional beliefs. Commentary Very little to support psychodynamic view of schizophrenia. Behaviour of parents assumed to be key influence in development of schizophrenia but may be consequence rather than cause. Cognitive explanations supported by neurophysiological evidence (Meyer-Lindenburg et al., 2002).

Socio-cultural factors Prior to schizophrenic episode, patients report twice as many stressful life events. Link demonstrated in both retrospective (Brown and Birley, 1968) and prospective (Hirsh et al,. 1996) studies. Double- bind theory- contradictory messages from parents prevent coherent construction of reality, leads to schizophrenic symptoms. Expressed emotion- family communication style involving criticism, hostility and emotional over-involvement. Leads to stress beyond impaired coping mechanisms and so schizophrenia. Labelling theory- symptoms of schizophrenia seen as deviant from rules ascribed to normal experience. Diagnostic label leads to self-fulfilling prophecy. Commentary Some evidence challenges link between life events and schizophrenia. Evidence for link is only correlational, not causal. Importance of family relationships in development of schizophrenia shown in adoption study by Tienari et al (1994). Double-bind theory supported by Berger (1965)- schizophrenics recalled more double-bind statements from mothers. Expressed emotion- has led to effective therapy for relatives. Scheff (1974)- 13 of 18 studies consistent with studies of labelling theory. Synoptic links - Expressed emotion effects much less common in non-individualist cultures.