People with this illness have changes in behavior and other symptoms -such as delusions and hallucinations – that last longer than 6 months. It usually affects them at work or school, as well as their relationships.

Schizophrenia is a chronic brain disorder that affects about one percent of the population. When schizophrenia is active, symptoms can include delusions, hallucinations, trouble with thinking and concentration, and lack of motivation. However, when these symptoms are treated, most people with schizophrenia will greatly improve over time.

While there is no cure for schizophrenia, research is leading to new, safer treatments. Experts also are unraveling the causes of the disease by studying genetics, conducting behavioral research, and by using advanced imaging to look at the brain’s structure and function. These approaches hold the promise of new, more effective therapies.

The complexity of schizophrenia may help explain why there are misconceptions about the disease. Schizophrenia does not mean split personality or multiple-personality. Most people with schizophrenia are not dangerous or violent. They also are not homeless nor do they live in hospitals. Most people with schizophrenia live with family, in group homes or on their own.

Research has shown that schizophrenia affects men and women about equally but may have an earlier onset in males. Rates are similar in all ethnic groups around the world. Schizophrenia is considered a group of disorders where causes and symptoms vary considerable between individuals.


When the disease is active, it can be characterized by episodes in which the patient is unable to distinguish between real and unreal experiences. As with any illness, the severity, duration and frequency of symptoms can vary; however, in persons with schizophrenia, the incidence of severe psychotic symptoms often decreases during a patient’s lifetime. Not taking medications as prescribed, use of alcohol or illicit drugs, and stressful situations tend to increase symptoms. Symptoms fall into several categories:

  • Positive psychotic symptoms: Hallucinations, such as hearing voices, paranoid delusions and exaggerated or distorted perceptions, beliefs and behaviors.
  • Negative symptoms: A loss or a decrease in the ability to initiate plans, speak, express emotion or find pleasure.
  • Disorganization symptoms: Confused and disordered thinking and speech, trouble with logical thinking and sometimes bizarre behavior or abnormal movements.
  • Impaired cognition: Problems with attention, concentration, memory and declining educational performance.

Symptoms usually first appear in early adulthood. Men often experience symptoms in their early 20s and women often first show signs in their late 20s and early 30s. More subtle signs may be present earlier, including troubled relationships, poor school performance and reduced motivation. It is rarely diagnosed in children or adolescents.

Before a diagnosis can be made, however, a psychiatrist should conduct a thorough medical examination to rule out substance misuse or other medical illnesses whose symptoms mimic schizophrenia.


Schizoaffective disorder

People have symptoms of both schizophrenia and a mood disorder, such as depression or bipolar disorder.

Schizoaffective disorder is a mental disorder in which a person experiences a combination of schizophrenia symptoms, such as hallucinations or delusions, and mood disorder symptoms, such as depression or mania. The two types of schizoaffective disorder — both of which include some symptoms of schizophrenia — are:

  • Bipolar type, which includes episodes of mania and sometimes major depression
  • Depressive type, which includes only major depressive episodes

Schizoaffective disorder may run a unique course in each affected person, so it’s not as well-understood or well-defined as other mental health conditions.

Untreated schizoaffective disorder may lead to problems functioning at work, at school and in social situations, causing loneliness and trouble holding down a job or attending school. People with schizoaffective disorder may need assistance and support with daily functioning. Treatment can help manage symptoms and improve quality of life.


Schizophreniform disorder

This includes symptoms of schizophrenia, but the symptoms last for a shorter time: between 1 and 6 months.

The characteristic symptoms of schizophreniform disorder are identical to those of Schizophrenia, but schizophreniform disorder is distinguished by its duration. An episode of the disorder (including prodromal, active, and residual phases) lasts at least one month but less than 6 months.

In some cases, the diagnosis is provisional because it is unclear whether the individual will recover from the disturbance within the 6-month period. If the disturbance persists beyond 6 months, the diagnosis should be changed to schizophrenia. Individuals who recover from schizophreniform disorder are projected to have a better functional prognosis.

Another way schizophreniform disorder differs from schizophrenia is that impaired social and occupational functioning are not required criteria. While such impairments may potentially be present, they are not necessary for a diagnosis of schizophreniform disorder. However, most individuals experience dysfunction in several areas of daily functioning, such as school or work, interpersonal relationships, and self-care.

Diagnostic criteria for schizophreniform disorders requires the following symptoms (with one being either 1, 2, or 3):

  1. Delusions
  2. Hallucinations (see schizophrenia for elaborated description of symptoms)
  3. Disorganized speech (communication is incoherent or seems like a “word salad”; frequent derailment of ideas)
  4. Disorganized or catatonic behavior
  5. Diminished range of emotional [removed]the person appears emotionally withdrawn)


Delusional disorder 

The key symptom is having a delusion (a false, fixed belief) involving real-life situations that could be true but aren’t, such as being followed, being plotted against, or having a disease. These delusions last for at least 1 month.

Delusions are fixed beliefs that do not change, even when a person is presented with conflicting evidence. Delusions are considered “bizarre” if they are clearly implausible and peers within the same culture cannot understand them. An example of a bizarre delusion is when an individual believes that his or her organs have been replaced with someone else’s without leaving any wounds or scars. An example of a nonbizarre delusion is the belief that one is under police surveillance, despite a lack of evidence.

Delusional disorder refers to a condition in which an individual displays one or more delusions for one month or longer. Delusional disorder is distinct from schizophrenia and cannot be diagnosed if a person meets the criteria for schizophrenia. If a person has delusional disorder, functioning is generally not impaired and behavior is not obviously odd, with the exception of the delusion. Delusions may seem believable at face value, and patients may appear normal as long as an outsider does not touch upon their delusional themes. Also, these delusions are not due to a medical condition or substance abuse.

There are several different types of delusional disorders, and each type captures a particular theme within a person’s delusions.

  • Erotomanic: An individual believes that a person, usually of higher social standing, is in love with him or her.
  • Grandiose: An individual believes that he or she has some great but unrecognized talent or insight, a special identity, knowledge, power, self-worth, or relationship with someone famous or with God.
  • Jealous: An individual believes that his or her partner has been unfaithful.
  • Persecutory: An individual believes that he or she is being cheated, spied on, drugged, followed, slandered, or somehow mistreated.
  • Somatic:  An individual believes that he or she is experiencing physical sensations or bodily dysfunctions, such as foul odors or insects crawling on or under the skin, or is suffering from a general medical condition or defect.
  • Mixed: An individual exhibits delusions that are characterized by more than one of the above types, but no one theme dominates.
  • Unspecified: An individual’s delusions do not fall into the described categories or cannot be clearly determined.

Additionally, delusional disorder can be specified as having bizarre content.

The most frequent type of delusional disorder is persecutory. Even so, this condition is rare, with an estimated 0.2 percent of people experiencing it at some point in their lifetime. Delusional disorder is equally likely to occur in males and females. Onset can vary from adolescence to late adulthood but tends to appear later in life.

Shared psychotic disorder (also called folie à deux)

This illness happens when one person in a relationship has a delusion and the other person in the relationship adopts it, too.

Shared psychotic disorder takes two people to happen, which is why it’s also called “folie a deux” or “the folly of two.” The first person – or the primary case – suffers from a mental health disorder, and the second person – or the secondary case, the one struggling with shared psychotic disorder – develops symptoms of the primary’s mental health disorder that are only present when in ongoing contact with that person. Otherwise healthy, the person diagnosed with shared psychotic disorder stops experiencing the mental health problems when they are no longer in contact with the person living with the primary disorder.

Substance-induced psychotic disorder

This condition is caused by the use of or withdrawal from drugs, such as hallucinogens and crack cocaine that cause hallucinations, delusions, or confused speech.

Prominent psychotic symptoms (i.e., hallucinations and/or delusions ) determined to be caused by the effects of a psychoactive substance is the primary feature of a substance-induced psychotic disorder. A substance may induce psychotic symptoms during intoxication (while the individual is under the influence of the drug) or during withdrawal (after an individual stops using the drug).


A substance-induced psychotic disorder is subtyped or categorized based on whether the prominent feature is delusions or hallucinations. Delusions are fixed, false beliefs. Hallucinations are seeing, hearing, feeling, tasting, or smelling things that are not there. In addition, the disorder is subtyped based on whether it began during intoxication on a substance or during withdrawal from a substance. A substance-induced psychotic disorder that begins during substance use can last as long as the drug is used. A substance-induced psychotic disorder that begins during withdrawal may first manifest up to four weeks after an individual stops using the substance.
Psychotic disorder due to another medical condition

Hallucinations, delusions, or other symptoms may happen because of another illness that affects brain function, such as a head injury or brain tumor.

This diagnosis is made when a patient’s medical history, physical examination, or laboratory test results suggest that one or more medical conditions have caused brain changes that might create psychotic symptoms, and those psychotic symptoms (e.g., hallucinations, delusions) are in fact present since the medical condition has occurred. A surprisingly large number of different medical conditions are capable of creating psychosis. Neurological conditions that may cause psychosis include brain tumors, cerebrovascular disease, Huntington’s disease, multiple sclerosis, epilepsy, auditory or visual nerve injury or impairment, deafness, migraine, and infections of the central nervous system. Endocrine disturbances include increases or decreases in the activity of the thyroid, parathyroid, or adrenocortical system. A decrease in blood gases such as oxygen or carbon dioxide or imbalances in blood sugar or electrolytes are some metabolic causes of psychosis. Finally, autoimmune disorders with central nervous system involvement such as systemic lupus erythematosus have also been known to cause psychosis.

Psychosis caused by a medical condition may be a single isolated incident or may be recurrent, cycling with the status of the underlying medical condition. Although treating the medical condition often results in the remission of the psychosis, this is not always the case. Psychotic symptoms may persist long after the medical conditions that have caused them are cured.

Paraphrenia: This condition has symptoms similar to schizophrenia. It starts late in life, when people are elderly.

Paraphrenia is not listed in the DSM as a diagnosis, but is still regarded by some practitioners as a separate diagnosis from related illnesses such as schizoaffective disorder and delusional disorder. For this reason, diagnosis with paraphrenia is fairly uncommon and people with symptoms of paraphrenia are more likely to be diagnosed with other disorders.

The disorder is similar to schizophrenia and other psychotic disorders. People with the disorder may experience delusions, strange or unusual thoughts or eccentric behavior. However, unlike schizophrenia, their personality is not usually fundamentally disturbed and they typically have normal affect. Paraphrenia tends to occur later in life – usually in the 40s or later – while schizophrenia and other psychotic disorders typically have their onset much earlier, in the teens and 20s. Paraphrenia is distinct from schizophrenia that persists or worsens late in life.

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