Treatment often involves the use of behavioral modification and anticonvulsants, antidepressants and anxiolytics.

An example of circumstantial speech is that when asked about the age of a person's mother at death, the speaker responds by talking at length about accidents and how too many people die in accidents, then eventually says what the mother's age was at death.

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.

The concept of thought disorder has been criticized as being based on circular or incoherent definitions. For example, thought disorder is inferred from disordered speech, based on the assumption that disordered speech arises because of disordered thought. Incoherence, or word salad, refers to speech that is unconnected and conveys no meaning to the listener.

Furthermore, although thought disorder is typically associated with psychosis, similar phenomena can appear in different disorders, potentially leading to misdiagnosis—for example, in the case of incomplete yet potentially fruitful thought processes.

It has been suggested that individuals with autism spectrum disorders (ASD) display language disturbances like those found in schizophrenia; a 2008 study found that children and adolescents with ASD showed significantly more illogical thinking and loose associations than control subjects. The illogical thinking was related to cognitive functioning and executive control; the loose associations were related to communication symptoms and to parent reports of stress and anxiety.

People with Geschwind syndrome reported higher rates of atypical or altered sexuality. In approximately half of affected individuals hyposexuality is reported. Less commonly, cases of hypersexuality have been reported.

Geschwind syndrome, also known as Gastaut-Geschwind, is a group of behavioral phenomena evident in some people with temporal lobe epilepsy. It is named for one of the first individuals to categorize the symptoms, Norman Geschwind, who published prolifically on the topic from 1973 to 1984. There is controversy surrounding whether it is a true neuropsychiatric disorder. Temporal lobe epilepsy causes chronic, mild, interictal (i.e. between seizures) changes in personality, which slowly intensify over time. Geschwind syndrome includes five primary changes; hypergraphia, hyperreligiosity, atypical (usually reduced) sexuality, circumstantiality, and intensified mental life. Not all symptoms must be present for a diagnosis. Only some people with epilepsy or temporal lobe epilepsy show features of Geschwind syndrome.

Where surgery is not recommended, further management options include new (including experimental) anticonvulsants, and vagus nerve stimulation. The ketogenic diet is also recommended for children, and some adults. Other options include brain cortex responsive neural stimulators, deep brain stimulation, stereotactic radiosurgery, such as the gamma knife, and laser ablation.

Epilepsy surgery has been performed since the 1860s and doctors have observed that it is highly effective in producing freedom from seizures. However, it was not until 2001 that a scientifically sound study was carried out to examine the effectiveness of temporal lobectomy.

Temporal lobe surgery can be complicated by decreased cognitive function. However, after temporal lobectomy, memory function is supported by the opposite temporal lobe; and recruitment of the frontal lobe. Cognitive rehabilitation may also help.

In the ICU, international guidelines recommend that every patient gets checked for delirium every day (usually twice or more a day) using a validated clinical tool. The two most widely used are the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC). There are translations of these tools in over 20 languages and they are used globally in many thousands of ICUs, and instructional videos and myriad implementation tips are available. It is not as important which tool is used as that the patient gets monitored. Without using one of these tools, 75% of ICU delirium is missed by the practicing team, which leaves the patient without any likely active interventions to help reduce the duration of his/her delirium.

The most salient component of the definition of delirium that nurses and other healthcare professionals use at the bedside is whether or not the patient can pay attention and follow simple commands (see videos and literature). The advent of daily monitoring for delirium, made easy by the CAM-ICU and other assessment tools, as well as proper documentation, had led to important changes in the culture of ICUs and rounds in that the entire team can now discuss the brain and how it is doing in terms of being “on” (not delirious) or “off” (delirious) and then focus on the several most likely causes of delirium in any specific patient. Thus, it is not the monitoring itself that changes the patient’s clinical course, but rather it is this combination of monitoring and then relaying the information on rounds in the ICU that makes such a huge difference in awareness of this form of organ dysfunction and then enables a difference to be made in clinical outcomes.

Multiple guidelines recommend that delirium should be diagnosed when it presents to healthcare services. Much evidence suggest, however, that delirium is greatly underdiagnosed. Higher rates of detection of delirium in general settings (for the ICU see below) can be assisted by the use of validated delirium screening tools. Many such tools have been published. They differ in duration, complexity, need for training, and so on. Examples of tools in use in clinical practice are: Delirium Observation Screening Scale, the Nursing Delirium Screening Scale (Nu-DESC), the Confusion Assessment Method, the Recognizing Acute Delirium As part of your Routine (RADAR) tool and the 4 "A"s Test or 4AT.