psychiatry: psychoses Flashcards
delusions definition
A delusion is a false belief which is firmly sustained and based on incorrect inference about reality. This belief is held despite evidence to the contrary and is not accounted for by the person’s culture or religion.
criteria for delusions
- Certainty - the patient believes the delusion absolutely.
- Incorrigibility - the belief can not be shaken.
- Impossibility - the delusion is without doubt untrue.
hallucination definition
a sensory perception which is experienced despite there being no external stimulus. Hallucinations can occur with any sense and thus be visual, auditory, olfactory, gustatory or tactile.
pseudohallucination definition
the patient is aware of a stimulus which they realise is in their mind, eg hearing a voice. This differentiates them from hallucinations, which can be localised in a three-dimensional space outside the body
psychosis definition
Misperception of thought and perceptions that arise from the patient’s own mind as reality, includes delusions and hallucinations. It is a symptom, not diagnosis.
Psychotic disorders include:
- Schizophrenia
- Schizoaffective disorder
- Delusional disorder
- Brief psychotic episodes
- Psychotic depression
- Bipolar affective disorder
- Drug-induced psychoses
schizophrenia epidemiology
incidence of 15.2 per 100,000 person-years. A systematic review reported a prevalence of 7.2/1,000 persons. Age of onset is usually <35 y for females
aetiology schizophrenia
Multiple factors: genetic, environmental and social. Short-lived illnesses similar to paranoid schizophrenia are associated with cocaine, amfetamines and cannabis. Cannabis especially in both established schizophrenia and in enhancing future risk of schizophrenia in those who have not yet developed psychotic symptoms.
differentials for schizophrenia
Differentials Organic disorders • Drug-induced psychosis - amphetamine, LSD, cannabis • Temporal lobe epilepsy • Encephalitis • Alcoholic hallucinosis • Dementia • Delirium due to infection, metabolic or toxic disturbance, neurological disease, endocrine cause, etc • Cerebral syphilis (still rare, although worldwide incidence of syphilis has been increasing) Psychiatric conditions • Mania • Psychotic depression
first rank or positive symptoms in schizophrenia
(ATPD – Aim To Pass Definitely) Auditory hallucinations, specifically: 1. Third person (two or more voices heard discussing the patient – 3rd person) 2. Running commentary 3. Thought echo
Thought disorder (passivity of thought – under external control)
- Thought withdrawal
- Thought insertion
- Thought broadcasting
Passivity experiences (delusions of control)
- Actions/feelings/impulses under external control
- Bodily sensations due to external influence
Delusional perception (two stage process)
- Normal perception of commonplace object/sight leads to…
- Sudden, intense, self-referential delusion (eg finding a coin on the ground leads to belief of messianic role)
second rank symptoms in schizophrenia
symptoms are common in schizophrenia but also occur in other disorders: catatonic behaviour, second-person auditory hallucinations.
current diagnosis of schizophrenia
At least 1 First rank symptom or persistent delusions + present for at least a month (ICD-10) or 6 months (DSM-IV-TR) + no drug intoxication, withdrawal, overd brain disease or prominent affective symptoms.
types of delusions in schizophrenia
- Persecutory (someone is out to harm the patient)
- Delusions of reference (patient is mentioned on TV or knows that people are taling about him/her)
- Formal thought disorder may occur:
a. Loosening of associations
b. Neologisms
c. Concrete thinking (inability to deal with abstract ideas)
d. Word salad
schizophrenia symptoms can be classified into:
- Positive (hallucinations, delusions)
- Negative (poverty of speech, flat affect, poor motivation, social withdrawal, lack of concern for social convention
- Cognitive (poor attention and memory)
types of schizophrenia
paranoid catatonic hebephrenic residual (chronic) undifferentiated (simple)
1st line treatment for schizophrenia
Atypical antipsychotics – Olanzapine, Risperidone, Quetiapine, Amisulpiride, Aripiprazole, Clozapine.
pharmacology of atypical antipsychotics
side effects
The pharmacology unusual
•Binds only weakly to D1 and D2
•Affinity for D4 ,5HT2, 5HT3
•Effect mediated through glutamatergic pathways?
•Unique side effects profile
•Superior to other antipsychotics
SE: anticholinergic, antiadrenergic, weight gain, sedation, vomiting, Rarely: agranulocytosis, cariomyopathy, pulmonary embolism.
traditional antipsychotics
chlorpromazine, Stelazine, Thioridazine, haloperidol,. Marked extrapyramidal side effects. Produce EPSE at clinically effective doses
hypothesis for schizphrenia positive symtptoms?
Dopamine hypothesis for positive symptoms: correlation between clinical doses of AP’s and potency to block D2 receptors. Psychogenic effects of DA enhanced drugs – amphetamine.
All current antipsychotics act on the post-synaptic site. Challenges to the theory: negative symptoms, treatment resistant schizophrenia (TRS). Maybe related to glumate? TRS associated with combination of relatively normal striatal dopamine synthesis capacity and elevated ACC glutamate levels
how much receptor occupancy is required to achieve clinical effectsi n schizophrenia treatment?
At least 60% D2 receptors occupancy is necessary to achieve clinical response
chlorpromazine pharmacology and side effects
blocks many different receptors: dopamine, alpha-adrenergic, cholinergic, histamine.
Side effects: ●↑QT interval → VT ●Agranulocytosis ●contact dermatitis and purple skin pigmentation ●dystonias ●neuroleptic malignant syndrome ●photosensitivity ●tardive dyskinesia
genreally, adverse effects of antipsychotics are:
- Dopaminergic: dystonia, parkinsonism, akathisia, TD, hyperprolactinaemia, NMS
- Anticholinergic: confusion, dry mouth, constipation, blurred vision, urinary retention, tachycardia rarely glaucoma
- Alpha adrenergic: postural hypotention, impotence, priapism
- Histaminergic: sedation, postural hypotention
- Serotoninergic: weight gain
also EPSEs
EPSEs are
Extrapyramidal Side Effects: dystonic reactions, akathisia, tardive dyskinesia,pseudoparkinsonism
•Cardiac effects
•Diabetes/Dyslipaedimia/Weight gain
•Sexual dysfunction
•Reduced seizure threshold
•Metabolic syndrome: combination of medical disorders that ↑ the risk of developing CVD and diabetes
•Neuroleptic Malignant Syndrome
Neuroleptic Malignant Syndrome (NMS)
Rare but potentially fatal
•A syndrome of sympathetic hyperactivity
•Associated with all antipsychotics
•But even antidepressants, Promethazine, Lithium
•Less than 1 % (FGA)
Symptoms and signs:
•Fever, rigidity, confusion, fluctuating consciousness
•Sympathetic instability
•Increased Creatin Kinase (CK)
•Leucocytosis
•Abnormal LFT’s
