Schizophrenia: Symptoms, Causes and How It Is Treated
Schizophrenia is one of the most misunderstood conditions in mental health, partly because its portrayal in film and media bears very little resemblance to the actual experience of the people who live with it. It is not the same as having a split personality, and it does not make someone inherently dangerous. It is a serious, long term mental health condition that affects the way a person thinks, perceives the world, and behaves.
Understanding what schizophrenia actually involves, what its early signs look like and what treatment can offer is important for affected individuals, their families and anyone who works alongside people with mental health conditions. This article covers the core facts without sensationalism.
What is schizophrenia?
Schizophrenia is a chronic mental health disorder characterised by disruptions in thinking, perception, emotional response and social behaviour. It affects roughly 1 percent of the global population and typically first appears in late adolescence or early adulthood, though it can emerge at any age.
The word schizophrenia comes from Greek roots meaning split mind, but this refers to a fragmentation of mental functions, not to multiple distinct personalities, which is a separate and entirely different condition. People with schizophrenia often have periods of relatively stable functioning and periods of acute symptoms, and the course and severity vary considerably from person to person.
The three categories of symptoms
Clinicians usually describe schizophrenia symptoms under three headings: positive symptoms, negative symptoms and cognitive symptoms. Understanding the distinction helps explain why the condition can present so differently between individuals.
Positive symptoms
Positive symptoms are experiences or behaviours that are added to normal experience, things that are present but should not be. They tend to be more visible and are often what people associate with the condition.
• Hallucinations: Perceiving things that are not there, most commonly hearing voices but also seeing, smelling, tasting or feeling things with no external source. Auditory hallucinations are the most common and can range from faint murmuring to clear, commanding or commenting voices.
• Delusions: Fixed false beliefs that are held with certainty despite clear evidence to the contrary. Common types include paranoid delusions, where the person believes they are being watched, followed or harmed, grandiose delusions, where they believe they have special powers or significance, and referential delusions, where ordinary events are believed to have special meaning directed at them.
• Disorganised thinking: Speech that jumps between loosely connected topics, derails mid sentence or becomes difficult to follow. Thought processes become fragmented.
• Disorganised or abnormal motor behaviour: Unpredictable agitation, unusual postures, repetitive movements or in some cases a state of unresponsiveness called catatonia.
Negative symptoms
Negative symptoms reflect the absence or reduction of normal functions. They are often less dramatic than positive symptoms but can be more persistent and more disabling in everyday life.
• Flat affect: A reduced range of emotional expression, with a flattened facial expression and monotone voice that does not reflect internal emotional states.
• Alogia: Reduced speech output, giving brief, empty replies or speaking very little unprompted.
• Avolition: A significant loss of motivation to initiate or sustain purposeful activities, including basic self care.
• Anhedonia: Reduced ability to experience pleasure from activities that would normally be enjoyable.
• Social withdrawal: Pulling away from relationships and social contact, not necessarily from choice but from diminished drive and capacity.
Negative symptoms are often mistaken for laziness, depression or indifference, which can lead to frustration on the part of families and carers who do not understand that these are symptoms of the condition rather than a failure of will.
Cognitive symptoms
• Difficulty sustaining attention and concentrating on tasks
• Working memory problems, particularly holding information in mind while using it
• Slow processing speed
• Difficulty planning, organising and executing sequences of actions
• Problems understanding social cues and others' mental states
Cognitive symptoms are among the features most closely linked to long term difficulties with employment, independent living and relationships, even when positive symptoms are well controlled by medication.
What causes schizophrenia?
The precise causes are not fully understood, but research consistently points to a combination of genetic, neurobiological, developmental and environmental factors. No single cause has been identified.
Genetics
Schizophrenia runs in families. A person with a first degree relative who has the condition has a roughly ten percent risk, compared with about one percent in the general population. Having a genetic vulnerability does not guarantee the condition will develop, and many people with the relevant genetic variants never develop schizophrenia at all. Research suggests hundreds of genetic variants each contribute a small amount to overall risk.
Brain structure and chemistry
Neuroimaging studies have identified differences in brain structure and function in people with schizophrenia, including reduced grey matter in certain regions and differences in the volume of fluid filled spaces in the brain. The dopamine hypothesis, which proposes that excess dopamine activity in some brain pathways underlies positive symptoms, has been influential and helps explain why medications that block dopamine receptors reduce these symptoms. However, it is now understood to be only part of the picture, with glutamate and other neurotransmitter systems also involved.
Prenatal and developmental factors
Complications during pregnancy and birth, maternal infection during pregnancy, extreme stress during foetal development and nutritional deficiencies in the mother have all been associated with increased risk. Being born in winter or spring is also slightly associated, possibly due to seasonal viral exposure. The brain continues developing into the mid twenties, and the late adolescent period when this development is still ongoing appears to be when the condition is most likely to emerge.
Environmental triggers
Cannabis use, particularly heavy use of high potency cannabis in adolescence, significantly increases the risk of psychosis in people who are genetically vulnerable. This association is one of the strongest preventable environmental risk factors that research has identified. Childhood trauma, social isolation, migration and living in urban environments are also associated with elevated risk, though the mechanisms are not fully established.
Risk factors
Family history in a first degree relative | Approximately 10x general population risk |
Identical twin with schizophrenia | Approximately 40 to 50 percent concordance |
Heavy cannabis use in adolescence | Significantly elevated risk, especially high potency varieties |
Prenatal complications or infection | Modest but consistent association |
Childhood trauma or adversity | Associated with increased psychosis risk |
Being male | Earlier onset and often more severe course in men |
How schizophrenia is diagnosed
There is no single test for schizophrenia. Diagnosis is made by a psychiatrist through a detailed clinical interview covering symptoms, their duration and their impact on functioning, together with a thorough history and a medical evaluation to rule out physical causes.
Symptoms must be present for at least six months and must include an active phase of at least one month to meet diagnostic criteria. Other possible causes, including substance use, thyroid conditions, neurological disorders and other psychiatric conditions such as bipolar disorder with psychotic features, must be excluded before the diagnosis is confirmed. Early psychosis services in many countries aim to assess and begin treatment as quickly as possible after symptoms appear, because earlier intervention generally leads to better outcomes.
Treatment
Schizophrenia is a long term condition but it is treatable, and many people live independent, fulfilling lives with the right support. Treatment is usually a combination of medication, psychological therapy and social and community support.
Antipsychotic medication
Antipsychotic medications are the cornerstone of treatment, particularly for managing positive symptoms. They work primarily by modulating dopamine activity. First generation antipsychotics were effective but often caused significant side effects, particularly movement related effects. Second generation antipsychotics introduced from the 1990s onward generally have a better side effect profile for many people, though they carry their own risks including weight gain and metabolic effects. Finding the right medication at the right dose often takes time and close collaboration between the person, their family and their psychiatric team. Stopping medication abruptly is a major cause of relapse.
Psychological therapies
Cognitive behavioural therapy adapted for psychosis has good evidence behind it for helping people manage distressing symptoms, identify triggers and develop coping strategies. Family therapy, which involves working with the whole family unit, reduces relapse rates and improves quality of life for both the person with schizophrenia and their family members. Supported employment programmes and social skills training help with the everyday functional difficulties that medication alone does not address.
Community and social support
Stable housing, supported daily structure, peer support, crisis planning and case management all contribute meaningfully to longer term outcomes. Social isolation worsens the course of the condition, so maintaining meaningful connection, even at a level lower than before the illness, is an important goal of rehabilitation.
Supporting someone with schizophrenia
• Learn what the condition involves so that symptoms are not interpreted as personal behaviour
• Stay calm during acute episodes, as heightened emotion can worsen distress
• Help with practical tasks such as appointments, medication management and paperwork, which become harder during episodes
• Encourage engagement with the clinical team without making it a condition of your support
• Look after your own wellbeing through carer support services and peer groups, because caring for someone with schizophrenia is genuinely demanding
• Take any mention of self harm or suicide seriously and contact the clinical team or emergency services immediately if there is immediate risk
Frequently Asked Questions
Q. Is schizophrenia the same as split personality?
A. No. Split personality, now more accurately called dissociative identity disorder, is a completely different condition. Schizophrenia involves disruptions in thinking, perception and motivation, not multiple distinct personalities. The confusion comes from a historical mistranslation of the condition's name.
Q. Can schizophrenia be cured?
A. There is currently no cure, but it is a manageable condition. With appropriate treatment, many people experience significant reduction in symptoms and lead fulfilling lives. A minority achieve sustained remission. Long term treatment and support are usually required.
Q. Are people with schizophrenia dangerous?
A. The vast majority of people with schizophrenia are not violent and are far more likely to be victims of crime than perpetrators. The association between schizophrenia and violence in media coverage is significantly exaggerated and reflects stigma rather than evidence.
Q. At what age does schizophrenia usually begin?
A. The most common age of onset is late teens to early thirties. Men tend to develop the condition earlier, typically late teens to mid twenties, while women more commonly develop it in their mid twenties to early thirties. Onset in childhood or after age 45 is much less common.
Q. Does cannabis cause schizophrenia?
A. Cannabis use, particularly heavy and regular use of high potency cannabis in adolescence, significantly increases the risk of developing psychosis in people who are genetically vulnerable. It does not cause schizophrenia in everyone who uses it, but for those with a predisposition it is one of the most significant modifiable risk factors.
Disclaimer
This article is for general information only and is not a substitute for professional medical or psychiatric advice, diagnosis or treatment. If you or someone you know is experiencing symptoms, please seek assessment from a qualified mental health professional. In a crisis, contact emergency services or a local crisis line immediately.
