3.9.9 Schizophrenia and psychosis

Schizophrenia

Schizophrenia is a chronic disorder characterised by psychosis and a deterioration in functionality. It is a complex condition that affects millions of people globally. A diagnosis of schizophrenia requires the presence of two or more symptoms, at least one of which must be a positive symptom.

According to the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), schizophrenia is diagnosed when symptoms cause a decrease in both social and occupational functioning for at least six months.

First-rank symptoms:

The first-rank symptoms of schizophrenia, also known as Schneider’s first-rank symptoms, are a set of symptoms that have been described as being highly specific for the diagnosis of schizophrenia. Here’s a table of Schneider’s first-rank symptoms:

Symptom:	Description:
Auditory hallucinations	Hearing voices or sounds that are not physically present
Thought insertion or withdrawal	The belief that one’s thoughts are being inserted into or removed from one’s mind
Delusions of control	The belief that one’s actions or feelings are being controlled by an outside force
Delusions of reference	The belief that neutral events have a special and personal meaning
Somatic passivity	The belief that one’s body or bodily sensations are being controlled by an outside force

It’s important to note that not all individuals with schizophrenia experience these symptoms and that these symptoms can also be present in other psychiatric disorders. A proper diagnosis should always be made by a qualified mental health professional.

DSM vs ICD:

Here’s a comparison of DSM-5 and ICD-11 diagnostic criteria for Schizophrenia in table format:

Criteria:	DSM-5:	ICD-11:
Two or more of the following symptoms present for at least one month	✓	✓
– Delusions
– Hallucinations
– Disorganized speech (e.g., frequent derailment or incoherence)
– Grossly disorganized or catatonic behaviour
– Negative symptoms (e.g., diminished emotional expression or avolition)
Symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning	✓	✓
Symptoms are not due to a medical condition or substance use	✓	✓
If mood episodes have occurred concurrently with the active-phase symptoms, their total duration has been brief relative to the duration of the active-phase symptoms	✓	–
Schizophrenia has never been absent for more than a month at a time	✓	–

Gross changes:

• A reduction in cerebral hemisphere weight, length and volume.
• Enlargement of the lateral ventricles (especially the temporal horns).
• White matter reductions in the parahippocampal gyrus or hippocampus.
• Basal ganglia volume reduction.
• Planum temporal is a highly lateralized brain structure involved with language. In schizophrenic patients, there is a consistent reversal of the normal left-larger-than-right asymmetry of the planum temporal surface is noted.

(Golan, 2017)

Histological changes:

• Reduced cell number or size in the hippocampus and the dorsolateral prefrontal cortex.
• Increased neuronal density.

Dopamine dysfunction:

Dopamine dysfunction remains the key factor in psychotic symptoms. Presynaptic dopamine dysfunction appears to mediate psychosis in schizophrenia. In patients with schizophrenia, alterations in dopamine function within the striatum cause delusions and psychosis

There are four dopaminergic pathways relevant to the pharmacology of antipsychotics in the treatment of schizophrenia are: – The mesolimbic pathway (positive symptoms) – The mesocortical pathway (negative symptoms) – The nigrostriatal pathway (extrapyramidal symptoms and tardive dyskinesia) – The tuberoinfundibular pathway (hyperprolactinemia) (Stahl, 2008).

(Guzman, Psychopharmacology Institute)

Psychosis

The term “psychosis“ is used to characterise mental disorders in which some sense of reality has been lost. This type of illness is referred to as a psychotic episode. Psychosis is characterized by symptoms such as delusions, hallucinations, disordered thinking, and disordered behaviour. A person’s ideas and perceptions are distorted while they are experiencing psychosis, and they could find it difficult to distinguish between what is genuine and what isn’t.

People from many walks of life are susceptible to psychosis. Psychosis frequently starts in a person’s late teens to mid-twenties. Each year, there are over 100,000 new instances of psychosis in the United States. In the United Kingdom, psychosis is a relatively common condition, with an estimated 1 in 100 people experiencing psychosis at some point in their lifetime.

Before psychosis takes hold, a person’s behaviour will typically shift. The following behaviours are red flags for psychosis: Delusions (false beliefs) and hallucinations are signs of psychosis (seeing or hearing things that others do not see or hear). Other signs include inappropriate behaviour and speech that is illogical or incomprehensible. Additionally, a person going through a psychotic episode may struggle with sadness, anxiety, sleep issues, social disengagement, lack of motivation, and general difficulties in functioning.

Psychosis can have a variety of causes. Psychosis could be a sign of a mental condition like bipolar disorder or schizophrenia. However, a person could go through psychosis without ever being given a schizophrenia or other mental disease diagnosis. Other factors include lack of sleep, general health issues, the overuse of alcohol or other drugs like marijuana, as well as some prescription prescriptions.

References:

(1) Golan, D.E., Armstrong, E.J. and Armstrong, A.W. (2017). Principles of pharmacology: the pathophysiologic basis of drug therapy. Philadelphia: Wolters Kluwer.

(2) psychopharmacologyinstitute.com. (n.d.). Psychopharmacology Institute. [online] Available at: https://psychopharmacologyinstitute.com/publication/the-four-dopamine-pathways-relevant-to-antipsychotics-pharmacology-2096.

(3) Stahl, S.M. (2008). Stahl’s essential psychopharmacology online: neuroscientific basis and practical applications. Cambridge: Cambridge University Press.