Schizophrenia and Other Psychotic Disorders: Changes in Perception, Thought and Reality Testing

Psychosis changes how a person perceives, interprets and organises reality. Schizophrenia is one possible long term psychotic disorder, but similar symptoms can arise from mood disorders, substances, medicines, delirium and physical illness. Early specialist assessment, collaborative treatment and systematic physical health monitoring improve safety and recovery.

What psychosis means Psychosis describes symptoms that alter perception, belief, thought organisation and reality testing. A person may hear voices, hold beliefs others do not share or find their thinking and speech difficult to organise. Psychosis is a clinical syndrome rather than one diagnosis. Several psychiatric, substance related and physical conditions can produce it. The person's experiences are real to them and should be explored respectfully rather than confronted, mocked or dismissed. What schizophrenia is Schizophrenia is a psychotic disorder involving characteristic positive, negative and cognitive symptoms over time. Diagnosis requires a longitudinal specialist assessment rather than one unusual experience or a single emergency presentation. Symptoms must cause meaningful disturbance or functional decline and cannot be explained better by substances, mood episodes or physical illness. Schizophrenia does not mean split personality, multiple personalities or inevitable lifelong institutional care. Psychotic disorders are not all schizophrenia A brief psychotic disorder can resolve after a relatively short episode. Schizophreniform disorder has a schizophrenia like syndrome lasting longer than brief psychosis but less than the duration required for schizophrenia. Delusional disorder mainly involves persistent delusions without the full characteristic syndrome of schizophrenia. Schizoaffective disorder combines substantial mood episodes with periods of psychosis occurring independently of those mood episodes. Reality testing Reality testing is the ability to compare internal experiences and beliefs with shared evidence and alternative explanations. During psychosis, this ability can become reduced, although insight varies greatly between people and over time. Someone may recognise that a voice could be illness related while still finding it frightening and compelling. Reduced insight is a symptom, not stubbornness, dishonesty or a moral failure. Positive symptoms Positive symptoms are experiences added to ordinary mental functioning. They include hallucinations, delusions and disorganised thought or speech. The word positive does not mean beneficial or desirable. Positive symptoms often attract attention during an acute episode, but they represent only part of the illness burden. Hallucinations A hallucination is a perception occurring without a corresponding external stimulus. Hearing voices is the commonest example in schizophrenia, but hallucinations can involve sight, touch, smell or taste. Voices may comment, converse, criticise, comfort or give instructions. The content, emotional impact, degree of control and any commands matter more for safety than the mere presence of a voice. Hearing voices does not always mean schizophrenia Voice hearing can occur in trauma related disorders, severe mood episodes, neurological illness, substance use and some non clinical experiences. Some people hear voices without distress, impaired functioning or a psychotic disorder. Bereavement related experiences can include briefly hearing or sensing the person who died. Assessment considers context, duration, associated symptoms, insight, distress and cultural meaning. Command hallucinations Command hallucinations instruct a person to perform an action. Commands can be harmless, frightening, self destructive or directed towards another person. Risk depends on the content, the person's belief in the voice, previous compliance, available means and ability to resist. Commands involving harm require urgent direct assessment without assuming that every voice will be obeyed. Delusions A delusion is a strongly held belief that remains fixed despite persuasive evidence and is not accepted within the person's cultural context. Persecutory delusions involve beliefs that others intend harm, surveillance or conspiracy. Grandiose delusions concern exceptional power, status, ability or identity. Other themes can involve bodily change, guilt, reference, control, religion or nihilism. Ideas of reference and passivity experiences An idea or delusion of reference involves believing that neutral events contain a special personal message. A television programme, song or stranger's gesture may seem directed specifically at the person. Passivity experiences involve feeling that thoughts, movements or emotions are controlled by an outside force. Thought insertion, withdrawal or broadcasting are related experiences involving disrupted ownership or privacy of thought. Delusions and understandable mistrust Not every suspicious belief is delusional. Discrimination, abuse, surveillance, exploitation and unsafe environments can create realistic mistrust. Clinicians should examine evidence, context and cultural experience rather than assuming that unfamiliar concerns are psychosis. A diagnosis must not be used to dismiss legitimate complaints or remove credibility automatically. Thought disorder Formal thought disorder describes disruption in the organisation and expression of thought. Speech may become difficult to follow because connections between ideas are loose, indirect or rapidly shifting. A person may give answers that move away from the question or use words in unusual ways. The clinician assesses the pattern over time and considers language, education, neurodevelopmental differences and cultural communication styles. Disorganised speech and behaviour Disorganised speech is the observable expression of disturbed thought organisation. Disorganised behaviour can include unpredictable actions, difficulty completing ordinary sequences or behaviour that appears unrelated to the setting. Severe disorganisation can impair eating, dressing, medication use and safe travel. Unusual behaviour alone does not establish psychosis without understanding its purpose and context. Negative symptoms Negative symptoms involve reduction or loss of ordinary emotional, motivational and social functioning. They include avolition, alogia, reduced emotional expression, anhedonia and social withdrawal. These symptoms can be less visible than hallucinations or delusions but often create substantial long term disability. They should not be described as laziness, poor character or deliberate refusal. Avolition Avolition means reduced motivation and difficulty starting or sustaining purposeful activity. The person may struggle with washing, cooking, study, work or keeping appointments. They can still care deeply about outcomes while feeling unable to translate intention into action. Depression, sedation, poverty, cognitive difficulty and physical illness can produce similar functional changes. Alogia Alogia means reduced quantity or spontaneous production of speech. Answers may be brief, and conversation can require considerable effort. This differs from choosing privacy, speaking another language or communicating through an autistic style. Medication effects, depression and anxiety can also reduce speech and require consideration. Reduced emotional expression Reduced emotional expression can affect facial movement, eye contact, gesture, vocal tone and visible responsiveness. The person's internal emotions may be stronger than their outward expression suggests. Relatives can mistakenly believe the person no longer cares or feels affection. Clinicians should not infer emotional absence solely from a flat facial expression. Anhedonia and social withdrawal Anhedonia means reduced pleasure or anticipation of pleasure. Social withdrawal can reflect low motivation, suspiciousness, stigma, depression, sensory overload or previous rejection. Some people want relationships but lack confidence or opportunities to reconnect. Recovery plans should address access, skills and safety rather than demanding social activity as proof of improvement. Primary and secondary negative symptoms Primary negative symptoms arise from the underlying psychotic disorder. Secondary negative symptoms can result from depression, anxiety, medication sedation, extrapyramidal effects, substance use or social deprivation. Persistent positive symptoms can also cause withdrawal through fear and mistrust. Identifying secondary causes matters because they may respond to specific treatment changes. Cognitive symptoms Psychotic disorders can affect attention, working memory, processing speed, planning and social cognition. These changes may interfere with education, work, appointments, budgeting and understanding complex information. Cognitive symptoms are not the same as low intelligence. Written instructions, repetition, practical support and occupational rehabilitation can reduce their functional impact. The course of illness varies Some people experience one psychotic episode and recover fully. Others have episodic relapses with stable periods between them. Some develop persistent symptoms requiring long term treatment and support. Early response, social circumstances, substance use, physical health and access to effective care influence outcomes. First episode psychosis First episode psychosis means the first recognised presentation of sustained psychotic symptoms. The initial diagnosis may remain uncertain while clinicians observe the course and exclude other causes. The person should be referred urgently to an early intervention in psychosis service. NICE quality standards expect adults with first episode psychosis to start EIP treatment within two weeks of referral. Early intervention in psychosis services EIP services provide multidisciplinary assessment and treatment during the early years of psychosis. Care can include medical treatment, CBT for psychosis, family work, physical healthcare, education and employment support. Teams also help with housing, substance use, relapse planning and engagement. The aim is not merely faster prescribing but coordinated recovery focused care. Duration of untreated psychosis Duration of untreated psychosis is the time between the onset of sustained psychotic symptoms and effective treatment. Longer untreated periods are associated with poorer symptom and functional outcomes on average. This association does not mean that delay alone determines an individual's future. Reducing avoidable delay remains important because timely treatment can reduce distress, disruption, relapse and hospital admission. Possible early changes Before clear psychosis, some people develop social withdrawal, reduced functioning, suspiciousness, sleep disruption or unusual perceptual experiences. These changes are non specific and occur in many other conditions. They should prompt assessment when persistent or worsening, especially alongside deteriorating functioning. Labelling someone as inevitably developing schizophrenia can itself cause harm and stigma. How schizophrenia is diagnosed Diagnosis is based on characteristic symptoms, duration, functional impact and exclusion of better explanations. DSM framing requires continuous disturbance for at least six months, including at least one month of active symptoms. At least one active symptom must be delusions, hallucinations or disorganised speech. International diagnostic systems differ slightly, so clinicians apply the framework used within their service. Comprehensive assessment Assessment covers positive, negative, cognitive, mood and trauma related symptoms. Clinicians ask about onset, duration, sleep, functioning, substances, medicines and physical health. Risk assessment includes suicide, self neglect, exploitation, command hallucinations and risk to others. Housing, relationships, education, employment, culture, spirituality and safeguarding are also relevant. Mental state examination The clinician observes appearance, behaviour, engagement, speech, mood, thought form, beliefs, perception, cognition and insight. The examination is a structured description rather than a judgement about personality. A calm appearance does not exclude severe delusions, command hallucinations or suicide risk. Communication support and interpreters should be used when needed. Collateral information Information from relatives, friends or professionals can clarify changes from usual functioning. This is particularly useful when insight, memory or thought organisation is impaired. The person's consent should be sought whenever possible. Information can still be received from carers even when confidentiality limits what clinicians can disclose back. Physical and neurological assessment A first psychotic presentation requires physical assessment because medical illness can alter perception, thought and behaviour. Observations can include temperature, pulse, blood pressure, oxygen level and hydration. Neurological examination is guided by symptoms such as seizures, focal weakness, movement change or altered consciousness. Emergency medical features take priority over psychiatric diagnostic classification. Investigations No blood test or brain scan confirms schizophrenia. Targeted investigations can include full blood count, electrolytes, kidney, liver, thyroid, glucose and toxicology testing. Pregnancy testing, infection assessment, autoimmune testing, EEG or imaging may be indicated by the presentation. Routine structural brain imaging is not recommended solely because a first psychotic episode has occurred. Substance induced psychosis Cannabis, cocaine, amphetamines, hallucinogens and other substances can produce psychotic symptoms. Prescribed or non prescribed corticosteroids, stimulants and dopaminergic medicines can also contribute. Diagnosis depends on the timing between exposure, intoxication, withdrawal and symptoms. Substance use can trigger psychosis in a vulnerable person and can coexist with an independent psychotic disorder. Cannabis and psychosis High potency and frequent cannabis use is associated with increased psychosis risk. Cannabis can worsen symptoms, relapse risk and treatment engagement after psychosis begins. This does not mean that every person using cannabis develops schizophrenia. Care should offer non judgemental substance support rather than making treatment conditional on immediate abstinence. Delirium Delirium is an acute disturbance of attention, awareness and cognition caused by physical illness, medicine effects or withdrawal. Symptoms fluctuate over hours or across the day, and consciousness or attention is impaired. Hallucinations and suspiciousness can occur, particularly in severe illness. Delirium is a medical emergency and must not be misdiagnosed as primary schizophrenia. Clues suggesting delirium Sudden onset, fluctuating alertness and inability to sustain attention strongly suggest delirium. Fever, low oxygen, infection, dehydration, metabolic disturbance or a new medicine can provide additional clues. Older adults and people with cognitive impairment are particularly vulnerable. Urgent investigation and treatment of the physical cause are required. Psychosis during mood episodes Severe depression can include mood congruent or mood incongruent psychotic features. Mania can include grandiose, persecutory or other psychotic symptoms. The relationship between mood episodes and psychosis helps distinguish mood disorders from schizophrenia spectrum disorders. These presentations follow the specialist pathways described in the Depression and Bipolar Disorder lessons. Trauma and dissociation Trauma related disorders can include voice hearing, hypervigilance, dissociation and unusual beliefs about danger. These experiences may overlap with psychosis while having different meanings and maintaining factors. Psychosis itself, restraint, admission and stigma can also be traumatic. NICE recommends assessing for trauma related reactions rather than assuming all distress arises from schizophrenia. Cultural and spiritual experiences Beliefs and experiences must be understood within the person's cultural, religious and spiritual context. An experience shared and accepted within a cultural community is not automatically a delusion or hallucination. Clinicians assess whether the experience is culturally congruent, involuntary, distressing, impairing or accompanied by disorganisation and reduced reality testing. Transcultural expertise or an appropriate cultural consultation can reduce misdiagnosis. Language and interpretation Language differences can make ordinary speech appear vague, indirect or disorganised. Family members should not routinely replace professional interpreters during sensitive diagnostic assessment. Idioms of distress and spiritual explanations should be explored rather than translated into psychiatric terminology automatically. A respectful assessment asks what the experience means to the person and their community. Schizophrenia is not caused by one factor Schizophrenia develops through interacting genetic, developmental, psychological and social influences. Adversity, trauma, urban stress, discrimination and substance exposure can alter vulnerability. Brain signalling differences are involved, but no single neurotransmitter imbalance explains the whole disorder. The diagnosis should not be used to blame the person or their family. Stigma and the violence stereotype Most people with schizophrenia are not violent. People with psychosis are often more vulnerable to self harm, exploitation, homelessness and becoming victims of violence. Risk can increase during untreated acute illness, severe fear, substance misuse or a history of violence, but it must be assessed individually. Using dangerous person stereotypes creates discrimination and can delay help seeking. Recovery focused care Recovery means building a meaningful and self directed life, whether or not every symptom disappears. Goals can include relationships, education, employment, housing, physical health and cultural or spiritual participation. Treatment should support autonomy and shared decision making. Risk management is necessary when danger is present but should not dominate every interaction. Antipsychotic medicines Antipsychotics reduce psychotic symptoms for many people and are recommended alongside psychological treatment for a first episode. They mainly reduce positive symptoms, while effects on negative and cognitive symptoms are more variable. No antipsychotic is best for every person. Choice considers previous response, adverse effects, physical health, formulation and the person's priorities. Shared decision making The clinician and person discuss expected benefits and side effects before choosing treatment. Relevant risks include weight gain, diabetes, movement disorders, prolactin elevation, sedation and QT prolongation. The person may prioritise avoiding one adverse effect over another. Carers can contribute when the person agrees, while the final plan should preserve the person's voice wherever capacity allows. First generation and second generation medicines Older terminology divides antipsychotics into first generation or typical and second generation or atypical medicines. The categories do not create a simple effectiveness or safety hierarchy. First generation medicines more often cause some movement effects, while several second generation medicines cause greater metabolic effects. Individual drugs differ substantially, making the specific side effect profile more useful than the category label alone. Starting treatment Antipsychotic treatment is an explicit individual therapeutic trial. NICE advises starting near the lower end of the licensed dose range and increasing gradually when needed. The indication, target symptoms, expected benefits and acceptable side effects should be recorded. Routine loading doses and regular antipsychotic combinations are avoided outside limited specialist circumstances. Realistic treatment timelines Sedation, sleep or agitation can change within the first days, but these changes do not prove that psychosis has resolved. Hallucinations, delusions and thought disorder often improve gradually over several weeks. NICE recommends an adequate trial at an optimum tolerated dose for four to six weeks before judging effectiveness. Severe deterioration, toxicity or intolerable effects require earlier review rather than waiting for the trial to finish. Monitoring response Reviews track target symptoms, distress, behaviour, functioning, adverse effects and adherence. Akathisia can resemble anxiety or agitation and may worsen distress if missed. Negative symptoms should be reassessed for depression, sedation and movement effects. Treatment success includes improved safety and participation, not simply reduced scores. Extrapyramidal symptoms Extrapyramidal symptoms are movement effects caused by dopamine blockade. Acute dystonia causes painful muscle spasms, often involving the neck, jaw or eyes. Parkinsonism causes stiffness, tremor and slowed movement, while akathisia causes severe inner restlessness. Tardive dyskinesia causes repetitive involuntary movements and can persist after medicine changes. Prolactin effects Some antipsychotics raise prolactin by blocking dopamine pathways involved in hormonal regulation. Possible effects include menstrual change, sexual dysfunction, breast symptoms, fertility difficulty and reduced bone health over time. Baseline prolactin is recorded before treatment under NICE guidance. Further prolactin testing follows symptoms, medicine specific risk and local monitoring arrangements. Cardiovascular effects and QTc Some antipsychotics prolong the QT interval, which can increase dangerous arrhythmia risk. An ECG is offered when required by the medicine information, cardiovascular history, examination findings or inpatient admission. Electrolyte abnormalities and other QT prolonging medicines can increase risk. Collapse, exertional fainting or sustained palpitations require urgent medical assessment. Baseline physical health monitoring Before starting an antipsychotic, NICE recommends recording weight, waist circumference, pulse and blood pressure. Testing includes fasting glucose or HbA1c, lipids and prolactin. Movement disorders, nutrition, diet and physical activity are also assessed. This baseline allows later changes to be detected rather than assumed. Monitoring after treatment begins Weight is monitored weekly for the first six weeks, then at twelve weeks, one year and annually. Pulse and blood pressure are checked at twelve weeks, one year and annually. Glucose or HbA1c and lipids are checked at twelve weeks, one year and annually. Waist circumference, movement effects, adherence and overall physical health are reviewed systematically. Metabolic syndrome Metabolic syndrome combines central adiposity, abnormal glucose regulation, raised blood pressure and adverse lipid patterns. Schizophrenia itself and several antipsychotics increase cardiometabolic vulnerability. Weight gain can begin rapidly after treatment starts, especially during a first episode. Early dietary, activity and medical intervention is more effective than waiting for established diabetes or cardiovascular disease. Annual physical health assessment Adults with psychosis or schizophrenia should receive a comprehensive physical health check at least annually. This includes cardiometabolic measures and attention to smoking, respiratory health and physical activity. Dental care, sexual health, vaccination and medicine related problems can also require support. Results should be shared between mental health and primary care teams through clear responsibility arrangements. Long acting injectable antipsychotics Long acting injections release medicine gradually over weeks or months. They can suit people who prefer fewer daily decisions or who have repeated relapse linked to missed oral doses. They should not be presented as punishment or proof of unreliability. Choice remains collaborative, with the same side effect monitoring required as for oral treatment. Psychological treatment Medication is not the only treatment for psychosis or schizophrenia. NICE recommends cognitive behavioural therapy for psychosis and family intervention. Social, occupational and educational support are also central to recovery. Psychological treatment should continue after discharge when begun during an acute episode. CBT for psychosis CBT for psychosis helps the person examine links between experiences, beliefs, emotions and behaviour. It does not require arguing that voices or beliefs are simply false. Work can reduce distress, test alternative explanations and develop coping strategies. NICE recommends individual CBT delivered over at least sixteen planned sessions. Family intervention Family intervention provides education, communication support, problem solving and relapse planning. It can reduce family stress and improve coping and relapse outcomes. NICE recommends it particularly when the person has close contact with family or has recently relapsed. Family involvement should not imply that relatives caused the illness. Carer support Carers can experience fear, exhaustion, financial strain and uncertainty. They should receive information, assessment of their own needs and access to carer focused support. Confidentiality does not prevent clinicians listening to information or providing general guidance. Immediate safety concerns may require proportionate information sharing. Occupational and social rehabilitation Supported employment can help people obtain and retain competitive work. Education support, benefits advice, housing assistance and occupational therapy can rebuild functioning. Cognitive difficulties may require reminders, task breakdown and reasonable adjustments. Recovery should not be delayed until every symptom has disappeared. Treatment adherence and shared problem solving Missed medication can arise from adverse effects, stigma, cognitive difficulty, homelessness, cost, beliefs or practical disruption. The response should identify the cause rather than label the person non compliant. Simplifying treatment, changing medicine, using reminders or offering a long acting formulation can help. Abrupt stopping increases relapse risk, especially during the first one to two years after an acute episode. When treatment does not help The team first reviews diagnosis, dose, duration, adherence, substances, interactions and physical illness. Two antipsychotics should be tried sequentially at adequate doses and durations before defining treatment resistance. At least one should be a non clozapine second generation antipsychotic under NICE criteria. Psychological and social interventions should also be reviewed rather than focusing only on tablets. Clozapine Clozapine is offered when schizophrenia has not responded adequately to at least two different antipsychotics. It is the antipsychotic with established efficacy for treatment resistant schizophrenia. Clozapine can also reduce suicidal behaviour in selected people but has important blood, cardiac, metabolic and gastrointestinal risks. Treatment requires registration, specialist prescribing and structured monitoring. Agranulocytosis and blood monitoring Clozapine can cause severe neutropenia or agranulocytosis, reducing the body's ability to fight infection. Mandatory full blood count and neutrophil monitoring is required under the current UK monitoring system. The medicine is supplied only when results meet the monitoring service's safety requirements. Clozapine blood level testing for toxicity does not replace the required haematological tests. Infection warning signs with clozapine Fever, sore throat, mouth ulcers or other infection symptoms require immediate contact with the clozapine service. An urgent blood count may be needed before further doses are supplied or taken. Pneumonia and serious infection can also raise clozapine concentrations and cause toxicity. The specialist team should advise whether treatment is paused and when it can restart. Other serious clozapine risks Clozapine can cause severe constipation, bowel obstruction, myocarditis, seizures, sedation and metabolic complications. Chest pain, breathlessness, persistent rapid pulse or flu like illness soon after starting requires urgent assessment for myocarditis. No bowel movement with abdominal pain, vomiting or distension requires emergency assessment. Smoking cessation can increase clozapine concentrations because tobacco smoke affects metabolism. Neuroleptic malignant syndrome Neuroleptic malignant syndrome is a rare but potentially fatal reaction to antipsychotic treatment. The classic pattern includes high temperature, severe muscle rigidity, confusion and autonomic instability. Autonomic changes include sweating, rapid pulse and unstable blood pressure. NMS is a medical emergency requiring immediate antipsychotic cessation and urgent hospital treatment. Differentiating NMS from ordinary side effects Mild stiffness or tremor can occur without NMS. The combination of fever, worsening rigidity, altered mental state and autonomic disturbance is particularly concerning. Blood tests can show raised creatine kinase, kidney injury and other systemic abnormalities. Treatment should not wait for every classic feature or laboratory result when clinical suspicion is high. Acute dystonia and akathisia Acute dystonia can cause eye deviation, jaw spasm, neck twisting or breathing difficulty. Airway involvement requires emergency treatment. Akathisia causes unbearable inner restlessness and can increase agitation or suicidal distress. Both require prompt medicine review rather than being mistaken for worsening psychosis. Suicide and self harm Psychotic disorders carry increased suicide risk, particularly early in illness and during depression or relapse. Voices commanding self harm, hopelessness, recent discharge and substance use increase concern. Clinicians ask directly about thoughts, plans, intent and access to means. Active intent or inability to remain safe requires same day crisis assessment. Risk to other people Risk assessment is individual and based on current symptoms, history, substances, access to weapons and specific threats. Persecutory fear or command hallucinations can occasionally increase acute risk. Most people with schizophrenia never act violently. Safety assessment should be thorough without treating the diagnosis itself as proof of dangerousness. Safeguarding and vulnerability Psychosis can increase vulnerability to exploitation, trafficking, financial abuse and unsafe relationships. Reduced self care can also affect children or dependent adults. Safeguarding action should be proportionate and explained wherever possible. Supporting autonomy and protecting from harm are not mutually exclusive goals. Relapse warning signs Personal warning signs can include reduced sleep, withdrawal, suspiciousness, missed appointments or increasing voice distress. Relapse plans identify preferred contacts, effective treatments and practical support. Family or carers can help notice change when the person agrees. Medication reduction should be gradual, with monitoring continuing for at least two years after withdrawal. Pregnancy and the postnatal period Pregnancy planning requires review of relapse history, medicine risks and available support. Stopping antipsychotics abruptly can cause relapse and should not occur without specialist advice. Postpartum psychosis can present with rapid mood change, confusion, hallucinations or delusions after childbirth. It is a psychiatric emergency requiring immediate specialist assessment. The central safety message Psychosis is a syndrome with several possible causes and does not automatically mean schizophrenia. First episode psychosis requires urgent EIP assessment because shorter untreated duration is linked with better outcomes. Treatment combines shared antipsychotic decisions, CBT for psychosis, family work and systematic physical health care. Command hallucinations, severe safety risk, delirium and neuroleptic malignant syndrome require urgent or emergency assessment.

Psychosis changes perception, belief, thought organisation and reality testing, but it has several possible causes. Early specialist assessment, collaborative antipsychotic and psychological treatment, physical health monitoring and stigma free support can reduce harm and improve long term recovery.