Schizophrenia

Etiology

 * Is essentially mutifactorial (not one gene responsible)


 * Genetics Concordance rate in monozygotic twins: 30-40%
 * Dopamine hypothesis
 * positive symptoms: due to excess dopamine in the mesolimbic pathway
 * negative symptoms: due to excess serotonin, decreased dopamine in prefrontal cortical pathways


 * Risk factors: cannabis association, living in an urban environment

Classification

 * The DSM-V does not adhere to the old classification of the DSM-IV (which is very similar to the classification of the ICD-10) since the subtypes do not reflect the entire spectrum of schizophrenia presentation
 * Important: It is not just one disease, but many

F20: Schizophrenia

F20.0 Paranoid schizophrenia: the most common form

F20.1 Hebephrenic schizophrenia

F20.2 Catatonic schizophrenia

F20.3 Undifferentiated schizophrenia

F20.4 Postschizophrenic depression

F20.5 Residual schizophrenia

F20.6 Simple schizophrenia

F20.8 Other schizophrenia

F20.9 Schizophrenia, unspecified

Details: https://icd.who.int/browse10/2014/en#!/F20-F29

Clinical criteria according to the DSM-V

 * at least 2 of the following, 1 of first 3 +
 * > 6 months


 * 1) Delusions: grandiosity, persecutions
 * 2) Hallucinations: auditory (think of a movie playing at the background)
 * 3) Disorganization: speech,
 * 4) Disorganization: behavior (e.g. stop leaving the house, stop grooming, wear thin foil hats)
 * 5) Any one negative symptoms: flat affect, poverty of speech, movement, anhedonia, cognitive impairment (psychotic break)

DDX

 * Acute psychosis due to acute intoxication (screen with urine) or a somatic condition (e.g. hepatic encephalopathy)
 * Other subtypes
 * Based on durations
 * Brief psychotic disorders: e.g. Post partum psychosis >1 d - <1 month
 * Schizophreniform disorder: > 1 month but < 6 month
 * Mood disorders and schizophrenia
 * Schizoaffective disorder
 * Psychosis predominates
 * Tx: treat mood first
 * Mood disorder with psychotic features

Links
https://www.youtube.com/watch/PURvJV2SMso (Osmosis, public domain)

https://onlinemeded.org/spa/psychiatry/psychotic-disorders/acquire

https://icd.who.int/browse10/2014/en#!/F20-F29