Cognitive dissonance is the mental conflict that people experience when they are presented with evidence that their beliefs or assumptions are wrong.

According to cognitive dissonance theory, there is a tendency for individuals to seek consistency among their cognitions (i.e., beliefs, opinions). When there is an inconsistency between attitudes or behaviors (dissonance), something must change to eliminate the dissonance. In the case of a discrepancy between attitudes and behavior, it is most likely that the attitude will change to accommodate the behavior.

For example, consider a situation in which a woman who values financial security is in a relationship with a man who is financially irresponsible.

The conflict:
• It is important for her to be financially secure.
• She is dating a man who is financially unstable.

In order to reduce this dissonance between belief and behavior, she can either leave the relationship or reduce her emphasis on financial security. In the case of the second option, dissonance could be further minimized by emphasizing the positive qualities of her significant other rather than focusing on his perceived flaws.

There are three key strategies to reduce or minimize cognitive dissonance:

1. • Focus on more supportive beliefs that outweigh the dissonant belief or behavior.
2. • Reduce the importance of the conflicting belief.
3. • Change the conflicting belief so that it is consistent with other beliefs or behaviors.
   

Dissociative Disorders

Depersonalization disorder (DPD) is a dissociative disorder in which the sufferer is affected by persistent or recurrent feelings of depersonalization and/or derealization.
Occasional moments of mild depersonalization are normal: strong, severe, persistent, or recurrent feelings are not.
Depersonalization disorder is marked by a feeling of detachment or distance from one's own experience, body, or self. These feelings of depersonalization are recurrent. Of the dissociative disorders, depersonalization is the one most easily identified with by the general public; one can easily relate to feeling as they in a dream, or being "spaced out." Feeling out of control of one's actions and movements is something that people describe when intoxicated. An individual with depersonalization disorder has this experience so frequently and so severely that it interrupts his or her functioning and experience. A person's experience with depersonalization can be so severe that he or she believes the external world is unreal or distorted.

Depersonalization disorder is a psychiatric disorder affecting emotions and behavior. It is characterized by an alteration in how an affected individual perceives or experiences his or her unique sense of self. The usual sense of one's own reality is temporarily lost or changed. A feeling of detachment from, or being an outside observer of, one's mental processes or body occurs such as the sensation of being in a dream.

Derealization (sometimes abbreviated as DR) is an alteration in the perception or experience of the external world so that it seems strange or unreal. Other symptoms include feeling as though one's environment is lacking in spontaneity, emotional coloring and depth.
Terms commonly used to describe Derealisation spaceyness... like looking through a grey veil... a sensory fog... being trapped in a glass bell jar... in a disney-world dream state... withdrawn... feeling cut off or distant from the immediate surroundings... like being a spectator at some strange and meaningless game... objects appear diminished in size, flat, dream-like, cartoon like, artificial... objects appear to be unsolid, to breathe, or to shimmer...

A fugue state, formally dissociative fugue or psychogenic fugue is a rare psychiatric disorder characterized by reversible amnesia for personal identity, including the memories, personality and other identifying characteristics of individuality. The state is usually short-lived (hours to days), but can last months or longer. Dissociative fugue usually involves unplanned travel or wandering, and is sometimes accompanied by the establishment of a new identity. After recovery from fugue, previous memories usually return intact, but there is complete amnesia for the fugue episode.

Dissociative identity disorder (DID) is a psychiatric diagnosis and describes a condition in which a person displays multiple distinct identities or personalities (known as alter egos or alters), each with its own pattern of perceiving and interacting with the environment.
Psychogenic amnesia, also known as functional amnesia or dissociative amnesia, is a memory disorder characterized by extreme memory loss that is caused by extensive psychological stress and that cannot be attributed to a known neurobiological cause. Psychogenic amnesia is defined by (a) the presence of retrograde amnesia (the inability to retrieve stored memories leading up to the onset of amnesia), and (b) an absence of anterograde amnesia (the inability to form new long term memories). Dissociative amnesia is due to psychological rather than physiological causes and can sometimes be helped by therapy.

There are two types of psychogenic amnesia, global and situation-specific. Global amnesia, also known as fugue state, refers to a sudden loss of personal identity that lasts a few hours to days, and is typically preceded by severe stress and/or depressed mood. Fugue state is very rare, and usually resolves over time, often helped by therapy. In most cases, patients lose their autobiographical memory and personal identity even though they are able to learn new information and perform everyday functions normally. Other times, there may be a loss of basic semantic knowledge and procedural skills such as reading and writing. Situation-specific amnesia occurs as a result of a severely stressful event, as in post-traumatic stress disorder, child sex abuse, military combat[8] or witnessing a family member's murder or suicide, and is somewhat common in cases of severe and/or repeated trauma

Dissociation

Dissociation is a partial or complete disruption of the normal integration of a person’s conscious or psychological functioning. Dissociation can be a response to trauma or drugs and perhaps allows the mind to distance itself from experiences that are too much for the psyche to process at that time. Dissociative disruptions can affect any aspect of a person’s functioning. Although some dissociative disruptions involve amnesia, some dissociative events do not. Since dissociations are normally unanticipated, they are typically experienced as startling, autonomous intrusions into the person's usual ways of responding or functioning. Due to their unexpected and largely inexplicable nature, they tend to be quite unsettling.

Different dissociative disorders have different relationships to stress and trauma.

The French philosopher and psychiatrist Pierre Janet (1859–1947) is considered to be the author of the concept of dissociation. He was a pioneering French psychologist, philosopher and psychotherapist in the field of dissociation and traumatic memory.

Contrary to most current conceptions of dissociation, Janet did not believe that dissociation was a psychological defense. Psychological defense mechanisms belong to Freud's theory of psychoanalysis, not to Janetian psychology. Janet claimed that dissociation occurred only in persons who had a constitutional weakness of mental functioning that led to hysteria when they were stressed. Although it is true that many of Janet's case histories described traumatic experiences, he never considered dissociation to be a defense against those experiences. Quite the opposite. Janet insisted that dissociation was a mental or cognitive deficit. Accordingly, he considered trauma to be one of many stressors that could worsen the already-impaired "mental efficiency" of a hysteric, thereby generating a cascade of hysterical (in today's language, "dissociative") symptoms.

Janet began his career as a philosopher, who used hypnosis to explore the dissociative propensities of the human mind. Following his doctoral dissertation in philosophy, he rapidly completed a medical degree and, with the sponsorship of J. M. Charcot[1], opened a laboratory in Pitié-Salpêtrière Hospital in Paris, where he continued his research into the nature and treatment of dissociative conditions. He was one of the first people to draw a connection between events in the subject's past life and his or her present day trauma, and coined the words ‘dissociation’ and ‘subconscious’. Hypnosis continued to be his investigative tool and therapeutic intervention of choice because it was, in his view, a form of dissociation. "Hypnotism may be defined as the momentary transformation of the mental state of an individual, artificially induced by a second person, and sufficing to bring about dissociations of personal memory". In several ways, he preceded Sigmund Freud.

[1]Jean-Martin Charcot (1825 –1893) was a French neurologist and professor of anatomical pathology. His work greatly influenced the developing fields of neurology and psychology. He was the "foremost neurologist of late nineteenth-century France" and has been called "the Napoleon of the neuroses". Charcot is best known today, outside the community of neurologists, for his work on hypnosis and hysteria. He believed that hysteria was a neurological disorder for which patients were pre-disposed by hereditary features of their nervous system. Charcot's interest in hysteria and hypnotism "developed at a time when the general public was fascinated in 'animal magnetism' and mesmerization'".