The current treatments for CCAS focus on relieving the symptoms. One treatment is a cognitive-behavioral therapy (CBT) technique that involves making the patient aware of his or hers cognitive problems. For example, many CCAS patients struggle with multitasking. With CBT, the patient would have to be aware of this problem and focus on just one task at a time. This technique is also used to relieve some motor symptoms. In a case study with a patient who had a stroke and developed CCAS, improvements in mental function and attention were achieved through reality orientation therapy and attention process training. Reality orientation therapy consists of continually exposing the patient to stimuli of past events, such as photos. Attention process training consists of visual and auditory tasks that have been shown to improve attention. The patient struggled in applying these skills to “real-life” situations. It was the help of his family at home that significantly helped him regain his ability to perform activities of daily living. The family would motivate the patient to perform basic tasks and made a regular schedule for him to follow.

Transcranial magnetic stimulation (TMS) has also been proposed to be a possible treatment of psychiatric disorders of the cerebellum. One study used TMS on the vermis of patients with schizophrenia. After stimulation, the patients showed increased happiness, alertness and energy, and decreased sadness. Neuropsychological testing post-stimulation showed improvements in working memory, attention, and visual spatial skill. Another possible method of treatment for CCAS is doing exercises that are used to relieve the motor symptoms. These physical exercises have been shown to also help with the cognitive symptoms.

Medications that help relieve deficits in traumatic brain injuries in adults have been proposed as candidates to treat CCAS. Bromocriptine, a direct D2 agonist, has been shown to help with deficits in executive function and spatial learning abilities. Methylphendiate has been shown to help with deficits in attention and inhibition. Neither of these drugs has yet been tested on a CCAS population. It may also be that some of the symptoms of CCAS improve over time without any formal treatment. In the original report of CCAS, four patients with CCAS were re-examined one to nine months after their initial neuropsychological evaluation. Three of the patients showed improvement in deficits without any kind of formal treatment, though executive function was still found to be one standard deviation below average. In one patient, the deficits worsened over time. This patient had cerebellar atrophy and worsened in visual spatial abilities, concept formation, and verbal memory. It should be noted that none of these treatments were tested on a large enough sample to determine if they would help with the general CCAS population. Further research needs to be done on treatments for CCAS.

Once it has been positively identified, pharmacotherapy follows. Antipsychotic drugs are the frontrunners in treatment for Fregoli and other DMSs. In addition to antipsychotics, anticonvulsants and antidepressants are also prescribed in some treatment courses. If a Fregoli patient has other psychological disorders, treatment often results in the use of trifluoperazine.

There is much research that needs to be conducted on CCAS. A necessity for future research is to conduct more longitudinal studies in order to determine the long-term effects of CCAS. One way this can be done is by studying cerebellar hemorrhage that occurs during infancy. This would allow CCAS to be studied over a long period to see how CCAS affects development. It may be of interest to researchers to conduct more research on children with CCAS, as the survival rate of children with tumors in the cerebellum is increasing. Hopefully future research will bring new insights on CCAS and develop better treatments.

Since the underlying cause of the disorder is damage to the brain, at present ideational apraxia is not reversible. However, Occupational or Physical Therapy may be able to slow the progression and help patients regain some functional control, with the treatment approach being the same as that of ideomotor apraxia. Some recovery may occur in younger patients after stroke, because brain plasticity may allow the functions of these damaged regions to be remapped. As patients develop new behaviors to cope with their apraxia, their brain's functioning neurons may take on some of the functions of the dead or damaged regions.

In the context of dementia, apraxia is a major cause of morbidity, and progresses with the underlying disease sometimes to the extent that patients may be unable to feed themselves or use simple utensils. Patients often become highly dependent or require nursing home placement because of their inability to properly use objects.

Brain imaging techniques such as fMRI, EEG, and PET scans may help in understanding the neuroanatomical and computational basis of ideational apraxia. Understanding these mechanisms is likely to be crucial in developing new modes of therapy to help patients cope with their disorder.

There is no cure for individuals with DES, but there are therapies to help them cope with their symptoms. DES can affect a number of functions in the brain and vary from person to person. Because of this variance, it is suggested that the most successful therapy would include multiple methods. Researchers suggest that a number of factors in the executive functioning need to be improved, including self-awareness, goal setting, planning, self-initiation, self-monitoring, self-inhibition, flexibility, and strategic behaviour.

One method for individuals to improve in these areas is to help them plan and carry out actions and intentions through a series of goals and sub-goals. To accomplish this, therapists teach patients a three-step model called the General Planning Approach. The first step is Information and Awareness, in which the patients are taught about their own problems and shown how this affects their lives. The patients are then taught to monitor their executive functions and begin to evaluate them. The second stage, Goal Setting and Planning, consists of patients making specific goals, as well as devising a plan to accomplish them. For example, patients may decide they will have lunch with a friend (their goal). They are taught to write down which friend it may be, where they are going for lunch, what time they are going, how they will get there, etc. (sub-goals). They are also taught to make sure the steps go in the correct order. The final stage, named Initiation, Execution, and Regulation, requires patients to implement their goals in their everyday lives. Initiation can be taught through normal routines. The first step can cue the patient to go to the next step in their plan. Execution and regulation are put into action with reminders of how to proceed if something goes wrong in the behavioural script. This treatment method has resulted in improved daily executive functioning, however no improvements were seen on formal executive functioning tests.

Since planning is needed in many activities, different techniques have been used to improve this deficit in patients with DES. Autobiographical memories can be used to help direct future behaviour. You can draw on past experiences to know what to do in the future. For example, when you want to take a bus, you know from past experience that you have to walk to the bus stop, have the exact amount of change, put the change in the slot, and then you can go find a seat. Patients with DES seem to not be able to use this autobiographical memory as well as a normal person. Training for DES patients asks them to think of a specific time when they did an activity previously. They are then instructed to think about how they accomplished this activity. An example includes "how would you plan a holiday". Patients are taught to think of specific times they went on a holiday and then to think how they may have planned these holidays. By drawing on past experiences patients were better able to make good decisions and plans.

Cognitive Analytic Therapy (CAT) has also been used to help those with DES. Because individuals with this syndrome have trouble integrating information into their actions it is often suggested that they have programmed reminders delivered to a cell phone or pager. This helps them remember how they should behave and discontinue inappropriate actions. Another method of reminding is to have patients write a letter to themselves. They can then read the letter whenever they need to. To help patients remember how to behave, they may also create a diagram. The diagram helps organize their thoughts and shows the patient how they can change their behaviour in everyday situations.

The use of auditory stimuli has been examined in the treatment of DES. The presentation of auditory stimuli causes an interruption in current activity, which appears to aid in preventing "goal neglect" by increasing the patients' ability to monitor time and focus on goals. Given such stimuli, subjects no longer performed below their age group average IQ.

Cognitive-behavioural therapy (CBT) is a frequently suggested treatment for executive dysfunction, but has shown limited effectiveness. However, a study of CBT in a group rehabilitation setting showed a significant increase in positive treatment outcome compared with individual therapy. Patients' self-reported symptoms on 16 different ADHD/executive-related items were reduced following the treatment period.

Palinopsia from cerebrovascular accidents generally resolves spontaneously, and treatment should be focused on the vasculopathic risk factors. Palinopsia from neoplasms, AVMs, or abscesses require treatment of the underlying condition, which usually also resolves the palinopsia. Palinopsia due to seizures generally resolves after correcting the primary disturbance and/or treating the seizures. In persistent hallucinatory palinopsia, a trial of an anti-epileptic drug can be attempted. Anti-epileptics reduce cortical excitability and could potentially treat palinopsia caused by cortical deafferentation or cortical irritation. Patients with idiopathic hallucinatory palinopsia should have close follow-up.

There is limited data on treating the visual disturbances associated with HPPD, persistent visual aura, or post-head trauma visual disturbances, and pharmaceutical treatment is empirically-based. It is not clear if the etiology or type of illusory symptom influences treatment efficacy. Since the symptoms are usually benign, treatment is based on the patient’s zeal and willingness to try many different drugs. There are cases which report successful treatment with clonidine, clonazepam, lamotrigine, nimodipine, topiramate, verapamil, divalproex sodium, gabapentin, furosemide, and acetazolamide, as these drugs have mechanisms that decrease neuronal excitability. However, other patients report treatment failure from the same drugs. Based on the available evidence and side-effect profile, clonidine might be an attractive treatment option. Many patients report improvement from sunglasses. FL-41 tinted lenses may provide additional relief, as they have shown some efficacy in providing relief to visually-sensitive migraineurs.

Treatment consists of high-dose lorazepam or in some cases ECT. The response to the treatment is usually good, especially if detected early

Since 1997 there has been experimental and clinical practice of psychosocial treatment for adults with executive dysfunction, and particularly attention-deficit/hyperactivity disorder (ADHD). Psychosocial treatment addresses the many facets of executive difficulties, and as the name suggests, covers academic, occupational and social deficits. Fifty percent of medication-based treatments for adults with ADHD are ineffective, so psychosocial treatment—although complicated and difficult to apply—is a promising alternative. Psychosocial treatment facilitates marked improvements in major symptoms of executive dysfunction such as time management, organization and self-esteem.

Perseveration according to psychology, psychiatry, and speech-language pathology, is the repetition of a particular response (such as a word, phrase, or gesture) regardless of the absence or cessation of a stimulus. It is usually caused by a brain injury or other organic disorder. Symptoms include "lacking ability to transition or switch ideas appropriately with the social context, as evidenced by the repetition of words or gestures after they have ceased to be socially relevant or appropriate", or the "act or task of doing so", and are not better described as stereotypy (a highly repetitive idiosyncratic behaviour).

In a broader sense, it is used for a wide range of functionless behaviours that arise from a failure of the brain to either inhibit prepotent responses or to allow its usual progress to a different behavior, and includes impairment in set shifting and task switching in social and other contexts.

The primary definition of perseveration in biology and clinical psychiatry involves some form of response repetition or the inability to undertake set shifting (changing of goals, tasks or activities) as required, and is usually evidenced by behaviours such as words and gestures continuing to be repeated despite absence or cessation of a stimulus.

More broadly in clinical psychology, it describes mental or physical behaviours which are not excessive in terms of quantity but are apparently both functionless and involve a narrow range of behaviours, and are not better described as stereotypy (a highly repetitive idiosyncratic behaviour).

In general English, perseveration (vb: "to perseverate") refers to insistent or redundant repetition, not necessarily in a clinical context.

No medications have been shown to prevent or cure dementia. Medications may be used to treat the behavioural and cognitive symptoms but have no effect on the underlying disease process.

Acetylcholinesterase inhibitors, such as donepezil, may be useful for Alzheimer disease and dementia in Parkinson's, DLB, or vascular dementia. The quality of the evidence however is poor and the benefit is small. No difference has been shown between the agents in this family. In a minority of people side effects include a slow heart rate and fainting.

As assessment for an underlying cause of the behavior is a needed before prescribing antipsychotic medication for symptoms of dementia. Antipsychotic drugs should be used to treat dementia only if non-drug therapies have not worked, and the person's actions threaten themselves or others. Aggressive behavior changes are sometimes the result of other solvable problems, that could make treatment with antipsychotics unnecessary. Because people with dementia can be aggressive, resistant to their treatment, and otherwise disruptive, sometimes antipsychotic drugs are considered as a therapy in response. These drugs have risky adverse effects, including increasing the patient's chance of stroke and death. Generally, stopping antipsychotics for people with dementia does not cause problems, even in those who have been on them a long time.

N-methyl-D-aspartate (NMDA) receptor blockers such as memantine may be of benefit but the evidence is less conclusive than for AChEIs. Due to their differing mechanisms of action memantine and acetylcholinesterase inhibitors can be used in combination however the benefit is slight.

While depression is frequently associated with dementia, selective serotonin reuptake inhibitors (SSRIs) do not appear to affect outcomes.

The use of medications to alleviate sleep disturbances that people with dementia often experience has not been well researched, even for medications that are commonly prescribed. In 2012 the American Geriatrics Society recommended that benzodiazepines such as diazepam, and non-benzodiazepine hypnotics, be avoided for people with dementia due to the risks of increased cognitive impairment and falls. Additionally, there is little evidence for the effectiveness of benzodiazepines in this population. There is no clear evidence that melatonin or ramelteon improves sleep for people with dementia due to Alzheimer's disease. There is limited evidence that a low dose of trazodone may improve sleep, however more research is needed.

There is no solid evidence that folate or vitamin B12 improves outcomes in those with cognitive problems. Statins also have no benefit in dementia. Medications for other health conditions may need to be managed differently for a person who also has a diagnosis of dementia. The MATCH-D criteria can help identify ways that a diagnosis of dementia changes medication management for other health conditions. It is unclear if there is a link between blood pressure medication and dementia. There is a possibility that people may experience an increase in cardiovascular-related events if these medications are withdrawn.

Perseveration of thought indicates an inability to switch ideas or responses. An example of perseveration is, during a conversation, if an issue has been fully explored and discussed to a point of resolution, it is not uncommon for something to trigger the reinvestigation of the matter. This can happen at any time during a conversation.

Physical brain injury, trauma or damage

- Perseveration is particularly common with those who have had traumatic brain injury.

- Perseveration is sometimes a feature of frontal lobe lesions, and of other conditions involving dysfunction or dysregulation within the frontal lobe. This is especially true when the lateral orbitofrontal cortex or inferior prefrontal convexity (Brodmann areas 47/12) are affected.

- Perseveration is also sometimes seen as a symptom of aphasia.

Other neurological conditions

- Perseveration may also refer to the obsessive and highly selective interests of individuals on the autism spectrum. This term is most connected to Asperger syndrome.

- In attention deficit hyperactivity disorder (ADHD), perseveration or "hyperfocus" commonly occurs as an impairment of set shifting and task switching. The resistance to transition may be a coping mechanism or the brain's method to compensate for the lack of ability to regulate the application of attention.

- In people who are both intellectually gifted and suffer a learning disability, the state of hyperfocus and flow can be confounded with perseverance.

- Apart from their direct symptoms, people with obsessive–compulsive disorder can have specific problems with set shifting and inhibition of prepotent responses.

Confounds (conditions with similar appearing symptoms)

- Perseveration may be confused with habitual behaviours in a number of other conditions and disorders, such as obsessive–compulsive disorder, including post-traumatic stress disorder (PTSD), body dysmorphic disorder, trichotillomania, and habit problems. However, in animal experiments it can be shown when repetitive behaviour is a cognitive perseveration rather than a motor disorder. For example, under low doses of amphetamine an animal will perseverate in maintaining an arbitrary object preference even when different motor responses are required to maintain that preference.

Unproven:

- Several researchers have tried to connect perseveration with a lack of memory inhibition (the person repeats the answer because they have not been able to forget a past question and move on to the current subject); however, this connection could not be found, or was small.

Dysexecutive syndrome (DES) consists of a group of symptoms, usually resulting from brain damage, that fall into cognitive, behavioural and emotional categories and tend to occur together. The term was introduced by Alan Baddeley to describe a common pattern of dysfunction in executive functions, such as planning, abstract thinking, flexibility and behavioural control. It is thought to be Baddeley's hypothesized working memory system and the central executive that are the hypothetical systems impaired in DES. The syndrome was once known as frontal lobe syndrome, however dysexecutive syndrome is preferred because it emphasizes the functional pattern of deficits (the symptoms) over the location of the syndrome in the frontal lobe, which is often not the only area affected.

Classification code in ICD-10 - F07

Intervention services will be guided by the strengths and needs determined by the speech and language evaluation. The areas of need may be addressed individually until each one is functional; alternatively, multiple needs may be addressed simultaneously through the intervention techniques. If possible, all interventions will be geared towards the goal of developing typical communicative interaction. To this end, interventions typically follow either a preventive, remedial, or compensatory model. The preventive service model is common as an early intervention technique, especially for children whose other disorders place them at a higher risk for developing later communication problems. This model works to lessen the probability or severity of the issues that could later emerge. The remedial model is used when an individual already has a speech or language impairment that he/she wishes to have corrected. Compensatory models would be used if a professional determines that it is best for the child to bypass the communication limitation; often, this relies on AAC.

Language intervention activities are used in some therapy sessions. In these exercises, an SLP or other trained professional will interact with a child by working with the child through play and other forms of interaction to talk to the child and model language use. The professional will make use of various stimuli, such as books, objects, or simple pictures to stimulate the emerging language. In these activities, the professional will model correct pronunciation, and will encourage the child to practice these skills. Articulation therapy may be used during play therapy as well, but involves modeling specific aspects of language—the production of sound. The specific sounds will be modeled for the child by the professional (often the SLP), and the specific processes involved in creating those sounds will be taught as well. For example, the professional might instruct the child in the placement of the tongue or lips in order to produce certain consonant sounds.

Technology is another avenue of intervention, and can help children whose physical conditions make communication difficult. The use of electronic communication systems allow nonspeaking people and people with severe physical disabilities to engage in the give and take of shared thought.

Binswanger's disease has no cure and has been shown to be the most severe impairment of all of the vascular dementias. The best way to manage the vascular risk factors that contribute to poor perfusion in the brain is to treat the cause, such as chronic hypertension or diabetes. It has been shown that current Alzheimer’s medication, donepezil (trade name Aricept), may help Binswanger’s Disease patients as well . Donepezil increases the acetylcholine in the brain through a choline esterase inhibitor which deactivates the enzyme that breaks down acetylcholine. Alzheimer as well as Binswanger patients have low levels of acetylcholine and this helps to restore the normal levels of neurotransmitters in the brain. This drug may improve memory, awareness, and the ability to function. If no medical interception of the disease is performed then the disease will continue to worsen as the patient ages due to the continuing atrophy of the white matter from whatever was its original cause.

The medications most frequently used are the selective serotonin reuptake inhibitors (SSRIs). Clomipramine, a medication belonging to the class of tricyclic antidepressants, appears to work as well as SSRIs but has a higher rate of side effects.

SSRIs are a second line treatment of adult obsessive compulsive disorder (OCD) with mild functional impairment and as first line treatment for those with moderate or severe impairment. In children, SSRIs can be considered as a second line therapy in those with moderate-to-severe impairment, with close monitoring for psychiatric adverse effects. SSRIs are efficacious in the treatment of OCD; people treated with SSRIs are about twice as likely to respond to treatment as those treated with placebo. Efficacy has been demonstrated both in short-term (6–24 weeks) treatment trials and in discontinuation trials with durations of 28–52 weeks.

In 2006, the National Institute of Clinical and Health Excellence (NICE) guidelines recommended antipsychotics for OCD that does not improve with SSRI treatment. For OCD the evidence for the atypical antipsychotic drugs risperidone and quetiapine is tentative with insufficient evidence for olanzapine. A 2014 review article found two studies that indicated that aripiprazole was "effective in the short-term" and found that "[t]here was a small effect-size for risperidone or anti-psychotics in general in the short-term"; however, the study authors found "no evidence for the effectiveness of quetiapine or olanzapine in comparison to placebo." While quetiapine may be useful when used in addition to an SSRI in treatment-resistant OCD, these drugs are often poorly tolerated, and have metabolic side effects that limit their use. None of the atypical antipsychotics appear to be useful when used alone. Another review reported that no evidence supports the use of first generation antipsychotics in OCD.

A guideline by the APA suggested that dextroamphetamine may be considered by itself after more well supported treatments have been tried.

Aromatherapy and massage have unclear evidence. There have been studies on the efficacy and safety of cannabinoids in relieving behavioral and psychological symptoms of dementia.

Omega-3 fatty acid supplements from plants or fish sources do not appear to benefit or harm people with mild to moderate Alzheimer's disease. It is unclear if taking omega-3 fatty acid supplements can improve other types of dementia.

Students identified with a speech and language disability often qualify for an Individualized Education Plan as well as particular services. These include one-on-one services with a speech and language pathologist. Examples used in a session include reading vocabulary words, identifying particular vowel sounds and then changing the context, noting the difference. School districts in the United States often have speech and language pathologists within a special education staff to work with students. Additionally, school districts can place students with speech and language disabilities in a resource room for individualized instruction. A combination of early intervention and individualized support has shown promise increasing long-term academic achievement with students with this disability.

Students might work individually with a specialist, or with a specialist in a group setting. In some cases, the services provided to these individuals may even be provided in the regular education classroom. Regardless of where these services are provided, most of these students spend small amounts of time in therapy and the large majority of their time in the regular education classroom with their typically developing peers.

Therapy often occurs in small groups of three or four students with similar needs. Meeting either in the office of the speech-language pathologist or in the classroom, sessions may take from 30 minutes to one hour. They may occur several times per week. After introductory conversations, the session is focused on a particular therapeutic activity, such as coordination and strengthening exercises of speech muscles or improving fluency through breathing techniques. These activities may take the form of games, songs, skits, and other activities that deliver the needed therapy. Aids, such as mirrors, tape recorders, and tongue depressors may be utilized to help the children to become aware of their speech sounds and to work toward more natural speech production.

The treatment for delirium with medications depends on its cause. Antipsychotics, particularly haloperidol, are the most commonly used drugs for delirium and the most studied. Evidence is weaker for the atypical antipsychotics, such as risperidone, olanzapine and quetiapine. British professional guidelines by the National Institute for Health and Clinical Excellence advise haloperidol or olanzapine. Antipsychotics however are not supported for the treatment or prevention of delirium among those who are in hospital.

Benzodiazepines themselves can cause delirium or worsen it, and there is no reliable evidence for use in non-alcohol-related delirium. If delirium is due to alcohol withdrawal or benzodiazepine withdrawal or if antipsychotics are contraindicated (e.g. in Parkinson's disease or neuroleptic malignant syndrome), then benzodiazepines are recommended. Similarly, people with dementia with Lewy bodies may have significant side-effects to antipsychotics, and should either be treated with a small dose or not at all.

The antidepressant trazodone is occasionally used in the treatment of delirium, but it carries a risk of oversedation, and its use has not been well studied.

Thought disorder (TD) or formal thought disorder (FTD) refers to disorganized thinking as evidenced by disorganized speech. Specific thought disorders include derailment, poverty of speech, tangentiality, illogicality, perseveration, and thought blocking.

Psychiatrists consider formal thought disorder as being one of two types of disordered thinking, with the other type being delusions. The latter involves "content" while the former involves "form". Although the term "thought disorder" can refer to either type, in common parlance it refers most often to a disorder of thought "form" also known as formal thought disorder.

Eugen Bleuler, who named schizophrenia, held that thought disorder was its defining characteristic. However, formal thought disorder is not unique to schizophrenia or psychosis. It is often a symptom of mania, and less often it can be present in other mental disorders such as depression. Clanging or echolalia may be present in Tourette syndrome. Patients with a clouded consciousness, like that found in delirium, also have a formal thought disorder.

However, there is a clinical difference between these two groups. Those with schizophrenia or psychosis are less likely to demonstrate awareness or concern about the disordered thinking. Clayton and Winokur have suggested that this results from a fundamental inability to use the same type of Aristotelian logic as others. On the other hand, patients with a clouded consciousness, referred to as "organic" patients, usually do demonstrate awareness and concern, and complain about being "confused" or "unable to think straight"; Clayton and Winokur suggest that this is because their thought disorder results, instead, from various cognitive deficits.

There have been assertions of a possible link between TGA and the use of statins (a class of drug used in treating cholesterol).

En bloc memory loss which is total, permanent, and irrecoverable can occur as an alcoholic "black out," usually lasting longer than an hour and up to 2–5 days.

Marijuana intoxication, Halogenated hydroxyquinolines such as Clioquinol, PDE inhibitors such as sildenafil, Digitalis and scopolamine intoxication, and general anaesthesia have been reported with TGA.

Ideational apraxia (IA) is a neurological disorder which explains the loss of ability to conceptualize, plan, and execute the complex sequences of motor actions involved in the use of tools or otherwise interacting with objects in everyday life. Ideational apraxia is a condition in which an individual is unable to plan movements related to interaction with objects, because he has lost the perception of the object's purpose. Characteristics of this disorder include a disturbance in the concept of the sequential organization of voluntary actions. The patient appears to have lost the knowledge or thought of what an object represents. This disorder was first seen 100 years ago by Doctor Arnold Pick, who described a patient who appeared to have lost their ability to use objects. The patient would make errors such as combing their hair with the wrong side of the comb or placing a pistol in his mouth. From that point on, several other

researchers and doctors have stumbled upon this unique disorder. IA has been described under several names such as, agnosia of utilization, conceptual apraxia or loss of knowledge about the use of tools, or semantic amnesia of tool usage. The term apraxia was first created by Steinthal in 1871 and was then applied by Gogol, Kusmaul, Star, and Pick to patients who failed to pantomime the use of tools. It was not until the 1900s, when Liepmann refined the definition, that it specifically described disorders that involved motor planning, rather than disturbances in the patient’s visual perception, language, or symbolism.

In considering whether an individual has thought disorder, patterns of their speech are closely observed. Although it is normal to exhibit some of the following during times of extreme stress (e.g. a cataclysmic event or the middle of a war) it is the degree, frequency, and the resulting functional impairment that leads to the conclusion that the person being observed has a thought disorder.

- "Alogia" (also "poverty of speech") – A poverty of speech, either in amount or content; it can occur as a negative symptom of schizophrenia.

- "Blocking" – An abrupt stop in the middle of a train of thought; the individual may or may not be able to continue the idea. This is a type of formal thought disorder that can be seen in schizophrenia.

- "Circumstantiality" (also "circumstantial thinking", or "circumstantial speech") – An inability to answer a question without giving excessive, unnecessary detail. This differs from tangential thinking, in that the person does eventually return to the original point.

- "Clanging" or "Clang association" – a severe form of flight of ideas whereby ideas are related only by similar or rhyming sounds rather than actual meaning. This may be heard as excessive rhyming and/or alliteration. e.g. "Many moldy mushrooms merge out of the mildewy mud on Mondays." "I heard the bell. Well, hell, then I fell." It is most commonly seen in bipolar affective disorder (manic phase), although it is often observed in patients with primary psychoses, namely schizophrenia and schizoaffective disorder.

- "Derailment" (also "loose association" and "knight's move thinking") – Thought and/or speech move, either spontaneously or in response to an internal stimulus (distinguishing derailment from "distractible speech," "infra"), from the topic's track onto another which is obliquely related or unrelated. e.g. "The next day when I'd be going out you know, I took control, like uh, I put bleach on my hair in California."

- "Distractible speech" – During mid speech, the subject is changed in response to an external stimulus. e.g. "Then I left San Francisco and moved to... where did you get that tie?"

- "Echolalia" – Echoing of another's speech that may only be committed once, or may be continuous in repetition. This may involve repeating only the last few words or last word of the examiner's sentences. This can be a symptom of Tourette's Syndrome. e.g. "What would you like for dinner?", "That's a good question. "That's a good question". "That's a good question". "That's a good question"."

- "Evasive interaction" – Attempts to express ideas and/or feelings about another individual come out as evasive or in a diluted form, e.g.: "I... er ah... you are uh... I think you have... uh-- acceptable erm... uh... hair."

- "Flight of ideas" – a form of formal thought disorder marked by abrupt leaps from one topic to another, albeit with discernable links between successive ideas, perhaps governed by similarities between subjects or, in somewhat higher grades, by rhyming, puns, and word plays (clang associations), or innocuous environmental stimuli – e.g., the sound of birds chirping. It is most characteristic of the manic phase of bipolar illness.

- "Illogicality" – Conclusions are reached that do not follow logically (non-sequiturs or faulty inferences). e.g. "Do you think this will fit in the box?" draws a reply like "Well duh; it's brown, isn't it?"

- "Incoherence (word salad)" – Speech that is unintelligible because, though the individual words are real words, the manner in which they are strung together results in incoherent gibberish, e.g. the question "Why do people comb their hair?" elicits a response like "Because it makes a twirl in life, my box is broken help me blue elephant. Isn't lettuce brave? I like electrons, hello please!"

- "Loss of goal" – Failure to follow a train of thought to a natural conclusion. e.g. "Why does my computer keep crashing?", "Well, you live in a stucco house, so the pair of scissors needs to be in another drawer."

- "Neologisms" – New word formations. These may also involve elisions of two words that are similar in meaning or in sound. e.g. "I got so angry I picked up a dish and threw it at the geshinker."

- "Perseveration" – Persistent repetition of words or ideas even when another person attempts to change the topic. e.g. "It's great to be here in Nevada, Nevada, Nevada, Nevada, Nevada." This may also involve repeatedly giving the same answer to different questions. e.g. "Is your name Mary?" "Yes." "Are you in the hospital?" "Yes." "Are you a table?" "Yes." Perseveration can include palilalia and logoclonia, and can be an indication of organic brain disease such as Parkinson's.

- "Phonemic paraphasia" – Mispronunciation; syllables out of sequence. e.g. "I slipped on the lice and broke my arm."

- "Pressure of speech" – Unrelenting, rapid speech without pauses. It may be difficult to interrupt the speaker, and the speaker may continue speaking even when a direct question is asked.

- "Self-reference" – Patient repeatedly and inappropriately refers back to self. e.g. "What's the time?", "It's 7 o'clock. That's my problem."

- "Semantic paraphasia" – Substitution of inappropriate word. e.g. "I slipped on the coat, on the ice I mean, and broke my book."

- "Stilted speech" – Speech characterized by the use of words or phrases that are flowery, excessive, and pompous. e.g. "The attorney comported himself indecorously."

- "Tangentiality" – Wandering from the topic and never returning to it or providing the information requested. e.g. in answer to the question "Where are you from?", a response "My dog is from England. They have good fish and chips there. Fish breathe through gills."

- "Word approximations" – Old words used in a new and unconventional way. e.g. "His boss was a ."

The Fregoli delusion, or the delusion of doubles, is a rare disorder in which a person holds a delusional belief that different people are in fact a single person who changes appearance or is in disguise. The syndrome may be related to a brain lesion and is often of a paranoid nature, with the delusional person believing themselves persecuted by the person they believe is in disguise.

A person with the Fregoli delusion can also inaccurately recall places, objects, and events. This disorder can be explained by "associative nodes". The associative nodes serve as a biological link of information about other people with a particular familiar face (to the patient). This means that for any face that is similar to a recognizable face to the patient, the patient will recall that face as the person they know.

The Fregoli delusion is classed both as a monothematic delusion, since it only encompasses one delusional topic, and as a delusional misidentification syndrome (DMS), a class of delusional beliefs that involves misidentifying people, places, or objects. Like Capgras delusion, psychiatrists believe it is related to a breakdown in normal face perception.