Prevention of schizophrenia is difficult as there are no reliable markers for the later development of the disorder. There is tentative evidence for the effectiveness of early interventions to prevent schizophrenia. While there is some evidence that early intervention in those with a psychotic episode may improve short-term outcomes, there is little benefit from these measures after five years. Attempting to prevent schizophrenia in the prodrome phase is of uncertain benefit and therefore as of 2009 is not recommended. Cognitive behavioral therapy may reduce the risk of psychosis in those at high risk after a year and is recommended in this group, by the National Institute for Health and Care Excellence (NICE). Another preventative measure is to avoid drugs that have been associated with development of the disorder, including cannabis, cocaine, and amphetamines.

Current methods in treating early-onset schizophrenia follow a similar approach to the treatment of adult schizophrenia. Although modes of treatment in this population is largely understudied, the use of antipsychotic medication is commonly the first line of treatment in addressing symptoms. Recent literature has failed to determine if typical or atypical antipsychotics are most effective in reducing symptoms and improving outcomes. When weighing treatment options, it is necessary to consider the adverse effects of various medications used to treat schizophrenia and the potential implications of these effects on development. A 2013 systematic review compared the efficacy of atypical antipsychotics versus typical antipsychotics for adolescents:

Madaan et al. wrote that studies report efficacy of typical neuroleptics such as thioridazine, thiothixene, loxapine and haloperidol, high incidence of side effects such as extrapyramidal symptoms, akathisia, dystonias, sedation, elevated prolactin, tardive dyskinesia.

Paranoid schizophrenia is an illness that typically requires lifelong treatment with neuroleptics to allow someone to have a relatively stable and normal lifestyle. In order to be successfully treated, a person with schizophrenia should seek help from family or primary care doctors, psychiatrists, psychotherapists, pharmacists, family members, case workers, psychiatric nurses, or social workers, provided he or she is not unable to do so, due to many people with schizophrenia having the inability to accept their condition. Non-compliance with neuroleptics may also occur if the patient considers the side effects (such as extrapyramidal symptoms) to be more debilitating than the condition itself. The main options that are offered for the treatment of paranoid schizophrenia are the following: neuroleptics, psychotherapy, hospitalization, electroconvulsive therapy, and vocational skills training.

There are many different types of disorders that have similar symptoms to paranoid schizophrenia. There are tests that psychiatrists perform to achieve a correct diagnosis. They include "psychiatric evaluation, in which the doctor or psychiatrist will ask a series of questions about the patient's symptoms, psychiatric history, and family history of mental health problems; medical history and exam, in which the doctor will ask about one's personal and family health history and will also perform a complete physical examination to check for medical issues that could be causing or contributing to the problem; laboratory tests in which the doctor will order simple blood and urine tests can rule out other medical causes of symptoms".

There are side effects associated with antipsychotic medication. Neuroleptics can cause high blood pressure and high cholesterol. Many people who take them exhibit weight gain and have a higher risk of developing diabetes.

The primary treatment of schizophrenia is antipsychotic medications, often in combination with psychological and social supports. Hospitalization may occur for severe episodes either voluntarily or (if mental health legislation allows it) involuntarily. Long-term hospitalization is uncommon since deinstitutionalization beginning in the 1950s, although it still occurs. Community support services including drop-in centers, visits by members of a community mental health team, supported employment and support groups are common. Some evidence indicates that regular exercise has a positive effect on the physical and mental health of those with schizophrenia.

According to the Mayo Clinic, it is best to start receiving treatment for paranoid schizophrenia as early as possible and to maintain the treatment throughout life. Continuing treatment will help keep the serious symptoms under control and allow the person to lead a more fulfilling life. This illness is typically unpreventable.

It has a strong hereditary component with a first degree parent or sibling. There is some possibility that there are environmental influences including "prenatal exposure to a viral infection, low oxygen levels during birth (from prolonged labor or premature birth), exposure to a virus during infancy, early parental loss or separation, and verbal, physical or sexual abuse in childhood". Eliminating any of these factors could help reduce an individual's future risk of developing paranoid schizophrenia.

Research efforts are focusing on prevention in identifying early signs from relatives with associated disorders similar with schizophrenia and those with prenatal and birth complications. Prevention has been an ongoing challenge because early signs of the disorder are similar to those of other disorders. Also, some of the schizophrenic related symptoms are often found in children without schizophrenia or any other diagnosable disorder.

Research suggests that paraphrenics respond well to antipsychotic drug therapy if doctors can successfully achieve sufficient compliance. Herbert found that Stelazine combined with Disipal was an effective treatment. It promoted the discharging of patients and kept discharged patients from being readmitted later. While behavior therapy may help patients reduce their preoccupation with delusions, psychotherapy is not currently of primary value.

Individuals who develop paraphrenia have a life expectancy similar to the normal population. Recovery from the psychotic symptoms seems to be rare, and in most cases paraphrenia results in in-patient status for the remainder of the life of the patient. Patients experience a slow deterioration of cognitive functions and the disorder can lead to dementia in some cases, but this development is no greater than the normal population.

The evidence for the effectiveness of early interventions to prevent psychosis appeared inconclusive. Whilst early intervention in those with a psychotic episode might improve short term outcomes, little benefit was seen from these measures after five years. However, there is evidence that cognitive behavioral therapy (CBT) may reduce the risk of becoming psychotic in those at high risk, and in 2014 the UK National Institute for Health and Care Excellence (NICE) recommended preventive CBT for people at risk of psychosis.

The treatment of psychosis depends on the specific diagnosis (such as schizophrenia, bipolar disorder or substance intoxication). The first-line psychiatric treatment for many psychotic disorders is antipsychotic medication, which can reduce the positive symptoms of psychosis in about 7 to 14 days.

The choice of which antipsychotic to use is based on benefits, risks, and costs. It is debatable whether, as a class, typical or atypical antipsychotics are better. Tentative evidence supports that amisulpride, olanzapine, risperidone and clozapine may be more effective for positive symptoms but result in more side effects. Typical antipsychotics have equal drop-out and symptom relapse rates to atypicals when used at low to moderate dosages. There is a good response in 40–50%, a partial response in 30–40%, and treatment resistance (failure of symptoms to respond satisfactorily after six weeks to two or three different antipsychotics) in 20% of people. Clozapine is an effective treatment for those who respond poorly to other drugs ("treatment-resistant" or "refractory" schizophrenia), but it has the potentially serious side effect of agranulocytosis (lowered white blood cell count) in less than 4% of people.

Most people on antipsychotics get side effects. People on typical antipsychotics tend to have a higher rate of extrapyramidal side effects while some atypicals are associated with considerable weight gain, diabetes and risk of metabolic syndrome; this is most pronounced with olanzapine, while risperidone and quetiapine are also associated with weight gain. Risperidone has a similar rate of extrapyramidal symptoms to haloperidol.

Before beginning treatment for mania, careful differential diagnosis must be performed to rule out secondary causes.

The acute treatment of a manic episode of bipolar disorder involves the utilization of either a mood stabilizer (valproate, lithium, or carbamazepine) or an atypical antipsychotic (olanzapine, quetiapine, risperidone, or aripiprazole). Although hypomanic episodes may respond to a mood stabilizer alone, full-blown episodes are treated with an atypical antipsychotic (often in conjunction with a mood stabilizer, as these tend to produce the most rapid improvement).

When the manic behaviours have gone, long-term treatment then focuses on prophylactic treatment to try to stabilize the patient's mood, typically through a combination of pharmacotherapy and psychotherapy. The likelihood of having a relapse is very high for those who have experienced two or more episodes of mania or depression. While medication for bipolar disorder is important to manage symptoms of mania and depression, studies show relying on medications alone is not the most effective method of treatment. Medication is most effective when used in combination with other bipolar disorder treatments, including psychotherapy, self-help coping strategies, and healthy lifestyle choices.

Lithium is the classic mood stabilizer to prevent further manic and depressive episodes. A systematic review found that long term lithium treatment substantially reduces the risk of bipolar manic relapse, by 42%. Anticonvulsants such as valproate, oxcarbazepine and carbamazepine are also used for prophylaxis. More recent drug solutions include lamotrigine, which is another anticonvulsant. Clonazepam (Klonopin) is also used. Sometimes atypical antipsychotics are used in combination with the previous mentioned medications as well, including olanzapine (Zyprexa) which helps treat hallucinations or delusions, Asenapine (Saphris, Sycrest), aripiprazole (Abilify), risperidone, ziprasidone, and clozapine which is often used for people who do not respond to lithium or anticonvulsants.

Verapamil, a calcium-channel blocker, is useful in the treatment of hypomania and in those cases where lithium and mood stabilizers are contraindicated or ineffective. Verapamil is effective for both short-term and long-term treatment.

Antidepressant monotherapy is not recommended for the treatment of depression in patients with bipolar disorders I or II, and no benefit has been demonstrated by combining antidepressants with mood stabilizers in these patients.

Involutional melancholia is classically treated with antidepressants and mood elevators.

Electroconvulsive therapy may also be used. Mid-century, there was a consensus that the technique indeed 'yields the best results in the long-lasting depressions of the change of life, the so-called "involutional melancholias", which before this form of treatment was introduced often required years of hospitalization'. The 21st century also records 'an excellent and rapid clinical response found in melancholia of recent onset...in older rather than younger patients' with ECT

The use of antipsychotic medication is commonly the first line of treatment; however, the effectiveness after treatment is in question.

L-DOPA is effective against reduced affect display and emotional withdrawal, aloofness from society, apathy.

Initial treatment is aimed at providing symptomatic relief. Benzodiazepines are the first line of treatment, and high doses are often required. A test dose of intramuscular lorazepam will often result in marked improvement within half an hour. In France, zolpidem has also been used in diagnosis, and response may occur within the same time period. Ultimately the underlying cause needs to be treated.

Electroconvulsive therapy (ECT) is an effective treatment for catatonia. Antipsychotics should be used with care as they can worsen catatonia and are the cause of neuroleptic malignant syndrome, a dangerous condition that can mimic catatonia and requires immediate discontinuation of the antipsychotic.

Excessive glutamate activity is believed to be involved in catatonia; when first-line treatment options fail, NMDA antagonists such as amantadine or memantine are used. Amantadine may have an increased incidence of tolerance with prolonged use and can cause psychosis, due to its additional effects on the dopamine system. Memantine has a more targeted pharmacological profile for the glutamate system, reduced incidence of psychosis and may therefore be preferred for individuals who cannot tolerate amantadine. Topiramate is another treatment option for resistant catatonia; it produces its therapeutic effects by producing glutamate antagonism via modulation of AMPA receptors.

Dementia praecox (a "premature dementia" or "precocious madness") is a disused psychiatric diagnosis that originally designated a chronic, deteriorating psychotic disorder characterized by rapid cognitive disintegration, usually beginning in the late teens or early adulthood. Over the years, the term "dementia praecox" was gradually replaced by "schizophrenia", which remains in current diagnostic use.

The term "dementia praecox" was first used in 1891 by Arnold Pick (1851–1924), a professor of psychiatry at Charles University in Prague. His brief clinical report described the case of a person with a psychotic disorder resembling hebephrenia. German psychiatrist Emil Kraepelin (1856–1926) popularised it in his first detailed textbook descriptions of a condition that eventually became a different disease concept and relabeled as schizophrenia. Kraepelin reduced the complex psychiatric taxonomies of the nineteenth century by dividing them into two classes: manic-depressive psychosis and dementia praecox. This division, commonly referred to as the Kraepelinian dichotomy, had a fundamental impact on twentieth-century psychiatry, though it has also been questioned.

The primary disturbance in dementia praecox was seen to be a disruption in cognitive or mental functioning in attention, memory, and goal-directed behaviour. Kraepelin contrasted this with manic-depressive psychosis, now termed bipolar disorder, and also with other forms of mood disorder, including major depressive disorder. He eventually concluded that it was not possible to distinguish his categories on the basis of cross-sectional symptoms.

Kraepelin viewed dementia praecox as a progressively deteriorating disease from which no one recovered. However, by 1913, and more explicitly by 1920, Kraepelin admitted that while there may be a residual cognitive defect in most cases, the prognosis was not as uniformly dire as he had stated in the 1890s. Still, he regarded it as a specific disease concept that implied incurable, inexplicable madness.

Few medications are approved specifically for schizoaffective disorder. In general, medications are chosen to reduce symptoms of psychosis and mood disorder.

Antipsychotic medication is usually required both for acute treatment and the prevention of relapse. There is no single antipsychotic of choice in treating schizoaffective disorder, but atypical antipsychotics should be considered because they have mood-stabilizing activity. Paliperidone is an antipsychotic with FDA approval for the treatment of schizoaffective disorder. Antipsychotics should be used at the minimum dose necessary to control symptoms. Potential side effects include extrapyramidal symptoms, including tremor, muscle stiffness, and restlessness or akathisia. Atypical antipsychotics carry a risk of metabolic syndrome, including weight gain, increased blood sugar, and increased blood cholesterol, so regular monitoring of weight and bloodwork should be carried out. Some atypical antipsychotics, such as ziprasidone and aripiprazole, are associated with less risk than others, such as olanzapine. Medication choice is based on how effectively it reduces symptoms, how few side effects it causes, and cost.

In people with treatment-refractory psychosis, a clozapine trial should be considered. Clozapine is an atypical antipsychotic that is recognized as being particularly effective when other antipsychotic agents have failed. Clozapine should also be considered in people with chronic and persistent suicidal thinking and behaviour, as it has been shown to reduce the risk of suicide in patients with schizoaffective disorder and a history of suicidality. Between 0.5 and 2% of patients taking clozapine may develop a life-threatening complication called agranulocytosis, which is a significant drop in a type of white blood cell. Because of this risk, people taking clozapine must have regular monitoring of blood cell counts.

The management of the bipolar type of schizoaffective disorder is similar to the treatment of bipolar disorder, with the goal of preventing mood episodes and cycling. Lithium or anticonvulsant mood stabilizers such as valproic acid, carbamazepine, and lamotrigine are prescribed in combination with an antipsychotic.

For depression, if an antidepressant is prescribed, "extra attentiveness must be given" by the prescribing clinician due its risk for long-term mood cycle acceleration (that is, inducing more frequent episodes of depression per unit of time) and medication-induced psychosis or mania. For individuals who show emerging psychosis, mania, mixed episode symptoms, or mood cycle acceleration, switching to an antipsychotic plus lithium or lamotrigine is preferable to antidepressants.

For individuals who experience anxiety, anti-anxiety medications can be used, usually on a short-term basis. Benzodiazepines, including lorazepam, clonazepam and diazepam, are types of anti-anxiety medications. Care must be taken when prescribing benzodiazepines due to the risk of the patient developing tolerance and dependence.

A number of medications are used to treat bipolar disorder. The medication with the best evidence is lithium, which is an effective treatment for acute manic episodes, preventing relapses, and bipolar depression. Lithium reduces the risk of suicide, self-harm, and death in people with bipolar disorder. It is unclear if ketamine is useful in bipolar as of 2015.

The article "Cotard's syndrome: A Review" (2010) reports successful pharmacological treatments (mono-therapeutic and multi-therapeutic) using antidepressant, antipsychotic, and mood stabilizing drugs; likewise, with the depressed patient, electroconvulsive therapy (ECT) is more effective than pharmacotherapy. Cotard syndrome resulting from an adverse drug reaction to valacyclovir is attributed to elevated serum concentration of one of valacyclovir's metabolites, 9-carboxymethoxymethylguanine (CMMG). Successful treatment warrants cessation of the drug, valacyclovir. Hemodialysis was associated with timely clearance of CMMG and resolution of symptoms.

The WHO first listed the condition in the 6th revision of the International Classification of Diseases ICD-6 (1949) and it stayed in the manual until the present version ICD-10.

Psychotherapy is aimed at alleviating core symptoms, recognizing episode triggers, reducing negative expressed emotion in relationships, recognizing prodromal symptoms before full-blown recurrence, and, practicing the factors that lead to maintenance of remission. Cognitive behavioral therapy, family-focused therapy, and psychoeducation have the most evidence for efficacy in regard to relapse prevention, while interpersonal and social rhythm therapy and cognitive-behavioral therapy appear the most effective in regard to residual depressive symptoms. Most studies have been based only on bipolar I, however, and treatment during the acute phase can be a particular challenge. Some clinicians emphasize the need to talk with individuals experiencing mania, to develop a therapeutic alliance in support of recovery.

Involutional melancholy's 'course was chronic, with agitation, depersonalization and delusions of bodily change and guilt' featuring strongly, but 'without manic features'. Symptoms of fear are also considered to occur, as well as despondency and hypochondriacal delusions. The late onset of the disorder was matched with a prolonged course with poor prognosis and/or deterioration, in the absence of treatment.

A challenge in the treatment of delusional disorders is that most patients have limited insight, and do not acknowledge that there is a problem. Most patients are treated as out-patients, although hospitalization may be required in some cases if there is a risk of harm to self or others. Individual psychotherapy is recommended rather than group psychotherapy, as patients are often quite suspicious and sensitive. Antipsychotics are not well tested in delusional disorder, but they do not seem to work very well, and often have no effect on the core delusional belief. Antipsychotics may be more useful in managing agitation that can accompany delusional disorder. Until further evidence is found, it seems reasonable to offer treatments which have efficacy in other psychotic disorders.

Psychotherapy for patients with delusional disorder can include cognitive therapy which is conducted with the use of empathy. During the process, the therapist can ask hypothetical questions in a form of therapeutic Socratic questioning. This therapy has been mostly studied in patients with the persecutory type. The combination of pharmacotherapy with cognitive therapy integrates treating the possible underlying biological problems and decreasing the symptoms with psychotherapy as well. Psychotherapy has been said to be the most useful form of treatment because of the trust formed in a patient and therapist relationship.

Supportive therapy has also been shown to be helpful. Its goal is to facilitate treatment adherence and provide education about the illness and its treatment.

Furthermore, providing social skills training has helped many persons. It can promote interpersonal competence as well as confidence and comfort when interacting with those individuals perceived as a threat.

Insight-oriented therapy is rarely indicated or contraindicated; yet there are reports of successful treatment. Its goals are to develop therapeutic alliance, containment of projected feelings of hatred, impotence, and badness; measured interpretation as well as the development of a sense of creative doubt in the internal perception of the world. The latter requires empathy with the patient's defensive position.

Electroconvulsive therapy, or ECT, may be considered for patients with schizoaffective disorder experiencing severe depression or severe psychotic symptoms that have not responded to treatment with antipsychotics.

Catatonia is a state of psycho-motor immobility and behavioral abnormality manifested by stupor. It was first described in 1874 by Karl Ludwig Kahlbaum, in ("Catatonia or Tension Insanity").

Though catatonia has historically been related to schizophrenia (catatonic schizophrenia), it is now known that catatonic symptoms are nonspecific and may be observed in other mental disorders and neurological conditions. In the fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM), catatonia is not recognized as a separate disorder, but is associated with psychiatric conditions such as schizophrenia (catatonic type), bipolar disorder, post-traumatic stress disorder, depression and other mental disorders, narcolepsy, as well as drug abuse or overdose (or both). It may also be seen in many medical disorders including infections (such as encephalitis), autoimmune disorders, focal neurologic lesions (including strokes), metabolic disturbances, alcohol withdrawal and abrupt or overly rapid benzodiazepine withdrawal. In the fifth edition of the DSM, it is written that a variety of medical conditions may cause catatonia, especially neurological conditions: encephalitis, cerebrovascular disease, neoplasms, head injury. Moreover, metabolic conditions: homocystinuria, diabetic ketoacidosis, hepatic encephalopathy, hypercalcaemia.

It can be an adverse reaction to prescribed medication. It bears similarity to conditions such as encephalitis lethargica and neuroleptic malignant syndrome. There are a variety of treatments available; benzodiazepines are a first-line treatment strategy. Electroconvulsive therapy is also sometimes used. There is growing evidence for the effectiveness of NMDA receptor antagonists for benzodiazepine-resistant catatonia. Antipsychotics are sometimes employed but require caution as they can worsen symptoms and have serious adverse effects.

Although cardiovascular risk factors, such as hypercholesterolaemia, hypertension, diabetes, and smoking, are associated with a higher risk of onset and course of AD, statins, which are cholesterol lowering drugs, have not been effective in preventing or improving the course of the disease.

Long-term usage of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced likelihood of developing AD. Evidence also supports the notion that NSAIDs can reduce inflammation related to amyloid plaques. No prevention trial has been completed. They do not appear to be useful as a treatment. Hormone replacement therapy in menopause, although previously used, may increase the risk of dementia.