Schizophrenia was first identified
more than a century ago, but we still don’t know its exact causes. It remains one of the most misunderstood
and stigmatized illnesses today. So, let’s walk through what we do know—
from symptoms to causes and treatments. Schizophrenia is considered a syndrome, which means it may encompass
a number of related disorders that have similar symptoms
but varying causes. Every person with schizophrenia
has slightly different symptoms, and the first signs can be easy to miss—
subtle personality changes, irritability, or a gradual encroachment
of unusual thoughts. Patients are usually diagnosed
after the onset of psychosis, which typically occurs in the late teens
or early twenties for men and the late twenties
or early thirties for women. A first psychotic episode can feature
delusions, hallucinations, and disordered speech and behavior. These are called positive symptoms, meaning they occur
in people with schizophrenia but not in the general population. It’s a common misperception
that people with schizophrenia have multiple personalities, but these symptoms indicate a disruption
of thought processes, rather than the manifestation
of another personality. Schizophrenia also has negative symptoms, these are qualities that are reduced
in people with schizophrenia, such as motivation,
expression of emotion, or speech. There are cognitive symptoms as well,
like difficulty concentrating, remembering information,
and making decisions. So what causes the onset of psychosis? There likely isn’t one single cause,
but a combination of genetic and environmental
risk factors that contribute. Schizophrenia has some of the strongest
genetic links of any psychiatric illness. Though about 1% of people
have schizophrenia, children or siblings of people
with schizophrenia are ten times likelier to develop the disease, and an identical twin
of someone with schizophrenia has a 40% chance of being affected. Often, immediate relatives
of people with schizophrenia exhibit milder versions of traits
associated with the disorder— but not to an extent
that requires treatment. Multiple genes almost certainly
play a role, but we don’t know how many, or which ones. Environmental factors like exposure
to certain viruses in early infancy might increase the chance
that someone will develop schizophrenia, and use of some drugs,
including marijuana, may trigger the onset of psychosis in highly susceptible individuals. These factors don’t affect
everyone the same way. For those with very low genetic risk, no amount of exposure
to environmental risk factors will lead them to develop schizophrenia; for those with very high risk, moderate
additional risk might tip the balance. The antipsychotic drugs used to treat
schizophrenia have helped researchers work backwards to trace signatures
of the disorder in the brain. Traditional antipsychotics
block dopamine receptors. They can be very effective
in reducing positive symptoms, which are linked to an excess of dopamine
in particular brain pathways. But the same drugs
can make negative symptoms worse, and we’ve found that negative symptoms
of schizophrenia may be tied to too little dopamine
in other brain areas. Some people with schizophrenia
show a loss of neural tissue, and it’s unclear whether this atrophy
is a result of the disease itself or drug-induced suppression of signaling. Fortunately, newer generations
of antipsychotics aim to address some of these issues by targeting
multiple neurotransmitters, like serotonin in addition to dopamine. It’s clear that no one transmitter system
is responsible for all symptoms, and because these drugs affect signaling
throughout the brain and body, they can have other
side effects like weight gain. In spite of these complications,
antipsychotics can be very effective, especially when combined
with other interventions like cognitive-behavioral therapy. Electroconvulsive therapy, though
it provides relatively short-lived relief, is also re-emerging
as an effective treatment, especially when other options
have failed. Early intervention
is also extremely important. After months or years
of untreated psychosis, certain psychoses can become embedded
in someone’s personality. And yet, the dehumanizing stigma
attached to this diagnosis can prevent people from seeking help. People with schizophrenia
are often perceived as dangerous, but are actually much more likely
to be the victims of violence than the perpetrators. And proper treatment may help reduce
the likelihood of violence associated with schizophrenia. That’s why education— for patients,
their families, and their communities— helps erode the stigma
and improves access to treatment.
