Bipolar disorder (also known as manic depression) is an affective disorder that causes periodic mood swings in which they cycle from depression to mania. Depression may be characterized by having a lack of motivation, difficulty doing tasks, short attention span, decreased appetite, crying spells, difficulty in getting to sleep or sleeping too much, and in the more severe cases thoughts of self harm. Mania is separated into two types: Full mania and hypomania. Mania may be characterized by a decreased need for sleep, decreased self-control, overspending, increased sexual activity, irritability, rage, risk-taking behaviors, and in the more severe cases psychotic states. Hypomania is described as having the same behaviors, to a less extreme level.

Of, relating to, or having a personality disorder characterized by habitual passive resistance to demands for adequate performance in occupational or social situations, as by procrastination, stubbornness, sullenness, and inefficiency.

Narcissistic Personality Disorder is a disorder in which a person has a grandiose self-importance, preoccupation with fantasies of unlimited success, a driven desire for attention and admiration, an intolerance of criticism, and disturbed self-centered interpersonal relations. They are often referred to as being conceited. They generally have a low self-esteem, as well. They act selfish interpersonally, with a sense of entitlement.

Schizophrenia is often thought of as "split personality". This is a misconception, as the person suffering from schizophrenia does not have more than one distinct personality as is seen in Dissociative Identity Disorder (Multiple Personality Disorder). Instead, they are characterized by having psychosis with, generally, two or more of the following: delusions, hallucinations (visual or auditory), disorganized speech (derailment of speech or incoherence), disorganized or catatonic behavior, or negative symptoms such as flattening of affect or lack of motivation.

Brief Psychotic Disorder is a psychosis that has a rapid onset, generally following a major stressor. Its hallmark is emotional turmoil, mood lability, and confusion. The sufferer must have one of the following symptoms: delusions, hallucinations, grossly disorganized or catatonic behavior, or disorganized speech. A brief psychotic episode is time limited, lasting at least a day, but less than a month. As a rule, the quicker the onset, the faster the recovery.

Dementia is categorized as being caused by four subtypes: Alzheimer's disease (the most common subtype, accounting for 50% of dementias); Vascular reasons (such as a stroke or hypertension, accounting for 9-15% of dementias); Substance abuse persisting dementias (accounting for 7-9% of dementias, with alcohol the major cause of most of these; and General medical conditions such as Parkinson's disease, Huntington disease, and other neurological illnesses (accounting for 20-30%). Psuedodementia can also be caused by other mental illnesses such as Major Depressive Disorder and Psychosis. Regardless of the cause, the dementias all have common factors. Initially in dementia, there is memory loss for recent events such as stoves being left on, keys being misplaced, conversations forgotten. Later, people begin to get lost while driving roads that they once knew very well, and questions must be repeated because the questions and answers are quickly forgotten. The long-ago memories are retained and dwelled upon. Personality changes occur, and the person may manifest changes that are the complete opposite from their previous personality. Poor judgment and impulse control often go hand-in-hand. They may speak crudely, make lewd gestures and display their genitals.

Bipolar disorder (also known as manic depression) is an affective disorder that causes periodic mood swings in which they cycle from depression to mania. Depression may be characterized by having a lack of motivation, difficulty doing tasks, short attention span, decreased appetite, crying spells, difficulty in getting to sleep or sleeping too much, and in the more severe cases thoughts of self harm. Mania is separated into two types: Full mania and hypomania. Mania may be characterized by a decreased need for sleep, decreased self-control, overspending, increased sexual activity, irritability, rage, risk-taking behaviors, and in the more severe cases psychotic states. Hypomania is described as having the same behaviors, to a less extreme level.

Essential features of Anorexia Nervosa are that the individual refuses to maintain a minimally normal body weight, is intensely afraid of gaining weight, and exhibits a significant disturbance in the perception of the shape or size of his or her body. The individual maintains a body weight that is below a minimally normal level for age and height.

Dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and / or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction.

Pyromania, like other impulse control disorders, shows a release of tension when the person sets the fire. They experience an inability to resist setting fires, and get gratification from watching them, as well. They do not feel remorse or regret for any part of the aftermath - from destruction of property to deaths. Unlike other impulse control disorders, they may do planning of their arson in advance, which also brings them pleasure.

Sleepwalking Disorder is the repeated act of getting out of bed and wandering around. This normally occurs during the first third part of the sleep cycle. The person is characterized by having a blank stare, is basically unresponsive to others, and will be difficult to wake. They can at times perform complex functions such as unlocking doors. The person will have no memory of the episode.