Schizophrenia is a complex psychiatric disorder usually characterised by thoughts disconnected from reality, perceptual disturbances, emotional dysregulation, and abnormal behaviour. It is a serious brain disorder that disrupts a person's thinking, emotions, and behaviour. Schizophrenia can significantly affect functioning and usually emerges in young adulthood or early adulthood.

Core symptoms of schizophrenia may include:

Delusions: False, irrational thoughts or beliefs. These may be paranoid (suspicious), grandiose (belief in special powers), or persecutory (belief that hostile forces are trying to control the person).
Hallucinations: Sensory experiences that are not real, usually auditory or visual. For example, the person may hear voices, see images, or experience tactile sensations.
Disorganised thinking: The person's thought process deviates from normal, with illogical connections, disordered language use, and disrupted thought patterns.
Emotional dysregulation: The person's emotions may be flatter or more intense than normal. Disruption in emotional expression and emotional coldness may also be seen.
Loss of functioning: Schizophrenia often seriously affects daily functioning. Problems may arise at work, school, and in social relationships.
Catatonic behaviour: Uncontrolled physical behaviour such as immobility or excessive movement.

Other disorders associated with schizophrenia and psychosis:

Schizoaffective Disorder: Involves both schizophrenic symptoms and mood disorder symptoms (bipolar type or major depressive type).
Schizotypal Personality Disorder: A personality disorder with schizoid features but without full schizophrenia-level symptoms.
Schizophreniform Disorder: Similar to schizophrenia but with a duration that does not meet full diagnostic criteria — usually at least one month and less than six months.
Psychotic Depression: Major depressive disorder accompanied by psychotic symptoms such as hallucinations or delusions.
Psychotic Bipolar Disorder: Bipolar disorder in which psychotic symptoms may occur during manic or depressive episodes.
Bipolar Disorder: A condition involving manic and depressive periods. During mania, symptoms such as excessive energy, increased speech rate, and accelerated thinking may appear, sometimes with psychotic features.

These disorders represent conditions that may be associated with schizophrenia or psychosis. Symptoms, duration, and impact differ for each disorder. It is important to consult a mental health professional for diagnosis and treatment.

Schizophrenia may arise from a complex interaction of genetic, biological, environmental, and neurological factors. Treatment should generally be maintained with antipsychotic medication and supportive psychotherapy. The treatment plan is usually personalised and long-term. Support services are also important for individuals living with schizophrenia and their families. Early diagnosis and appropriate treatment can help manage symptoms and improve quality of life.