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Schizophrenia was first identified 
more than a century ago,

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but we still don’t know its exact causes.

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It remains one of the most misunderstood 
and stigmatized illnesses today.

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So, let’s walk through what we do know— 
from symptoms to causes and treatments.

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Schizophrenia is considered a syndrome,

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which means it may encompass 
a number of related disorders

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that have similar symptoms 
but varying causes.

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Every person with schizophrenia 
has slightly different symptoms,

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and the first signs can be easy to miss— 
subtle personality changes, irritability,

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or a gradual encroachment 
of unusual thoughts.

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Patients are usually diagnosed 
after the onset of psychosis,

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which typically occurs in the late teens 
or early twenties for men

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and the late twenties 
or early thirties for women.

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A first psychotic episode can feature 
delusions, hallucinations,

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and disordered speech and behavior.

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These are called positive symptoms,

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meaning they occur 
in people with schizophrenia

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but not in the general population.

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It’s a common misperception 
that people with schizophrenia

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have multiple personalities,

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but these symptoms indicate a disruption 
of thought processes,

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rather than the manifestation 
of another personality.

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Schizophrenia also has negative symptoms,

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these are qualities that are reduced 
in people with schizophrenia,

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such as motivation, 
expression of emotion, or speech.

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There are cognitive symptoms as well, 
like difficulty concentrating,

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remembering information, 
and making decisions.

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So what causes the onset of psychosis?

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There likely isn’t one single cause,
but a combination

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of genetic and environmental 
risk factors that contribute.

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Schizophrenia has some of the strongest 
genetic links of any psychiatric illness.

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Though about 1% of people 
have schizophrenia,

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children or siblings of people 
with schizophrenia are ten times likelier

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to develop the disease,

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and an identical twin 
of someone with schizophrenia

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has a 40% chance of being affected.

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Often, immediate relatives 
of people with schizophrenia

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exhibit milder versions of traits 
associated with the disorder—

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but not to an extent 
that requires treatment.

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Multiple genes almost certainly 
play a role,

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but we don’t know how many, or which ones.

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Environmental factors like exposure 
to certain viruses in early infancy

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might increase the chance 
that someone will develop schizophrenia,

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and use of some drugs, 
including marijuana,

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may trigger the onset of psychosis

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in highly susceptible individuals.

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These factors don’t affect 
everyone the same way.

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For those with very low genetic risk,

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no amount of exposure 
to environmental risk factors

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will lead them to develop schizophrenia;

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for those with very high risk, moderate 
additional risk might tip the balance.

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The antipsychotic drugs used to treat 
schizophrenia have helped researchers

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work backwards to trace signatures 
of the disorder in the brain.

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Traditional antipsychotics 
block dopamine receptors.

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They can be very effective 
in reducing positive symptoms,

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which are linked to an excess of dopamine 
in particular brain pathways.

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But the same drugs 
can make negative symptoms worse,

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and we’ve found that negative symptoms 
of schizophrenia may be tied

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to too little dopamine 
in other brain areas.

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Some people with schizophrenia 
show a loss of neural tissue,

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and it’s unclear whether this atrophy 
is a result of the disease itself

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or drug-induced suppression of signaling.

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Fortunately, newer generations 
of antipsychotics aim to address

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some of these issues by targeting 
multiple neurotransmitters,

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like serotonin in addition to dopamine.

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It’s clear that no one transmitter system 
is responsible for all symptoms,

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and because these drugs affect signaling 
throughout the brain and body,

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they can have other 
side effects like weight gain.

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In spite of these complications, 
antipsychotics can be very effective,

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especially when combined 
with other interventions

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like cognitive-behavioral therapy.

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Electroconvulsive therapy, though 
it provides relatively short-lived relief,

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is also re-emerging 
as an effective treatment,

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especially when other options 
have failed.

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Early intervention 
is also extremely important.

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After months or years 
of untreated psychosis,

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certain psychoses can become embedded 
in someone’s personality.

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And yet, the dehumanizing stigma 
attached to this diagnosis

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can prevent people from seeking help.

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People with schizophrenia 
are often perceived as dangerous,

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but are actually much more likely 
to be the victims of violence

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than the perpetrators.

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And proper treatment may help reduce 
the likelihood of violence

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associated with schizophrenia.

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That’s why education— for patients, 
their families, and their communities—

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helps erode the stigma 
and improves access to treatment.