Obsessive–compulsive disorder (OCD) is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions. Symptoms of the disorder include excessive washing or cleaning; repeated checking; extreme hoarding; preoccupation with sexual, violent or religious thoughts; aversion to particular numbers; and nervous rituals, such as opening and closing a door a certain number of times before entering or leaving a room. These symptoms can be alienating and time-consuming, and often cause severe emotional and financial distress. The acts of those who have OCD may appear paranoid and potentially psychotic. However, OCD sufferers generally recognize their obsessions and compulsions as irrational, and may become further distressed by this realization.

Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or more depressive episodes. The elevated moods are clinically referred to as mania or, if milder, hypomania. Individuals who experience manic episodes also commonly experience depressive episodes, or symptoms, or a mixed state in which features of both mania and depression are present at the same time.[1] These events are usually separated by periods of "normal" mood; but, in some individuals, depression and mania may rapidly alternate, which is known as rapid cycling. Severe manic episodes can sometimes lead to such psychotic symptoms as delusions and hallucinations. The disorder has been subdivided into bipolar I, bipolar II, cyclothymia, and other types, based on the nature and severity of mood episodes experienced; the range is often described as the bipolar spectrum.

Major depressive disorder (MDD) (also known as recurrent depressive disorder, clinical depression, major depression, unipolar depression, or unipolar disorder) is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities. This cluster of symptoms (syndrome) was named, described and classified as one of the mood disorders in the 1980 edition of the American Psychiatric Association's diagnostic manual. The term "depression" is ambiguous. It is often used to denote this syndrome but may refer to other mood disorders or to lower mood states lacking clinical significance. Major depressive disorder is a disabling condition that adversely affects a person's family, work or school life, sleeping and eating habits, and general health. In the United States, around 3.4% of people with major depression commit suicide, and up to 60% of people who committed suicide had depression or another mood disorder.[1]

The diagnosis of major depressive disorder is based on the patient's self-reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no laboratory test for major depression, although physicians generally request tests for physical conditions that may cause similar symptoms. If depressive disorder is not detected in the early stages it may result in a slow recovery and affect or worsen the person's physical health. Standardized screening tools such as Major Depression Inventory can be used to detect major depressive disorder.[2][3] The most common time of onset is between the ages of 20 and 30 years, with a later peak between 30 and 40 years.[4]

Typically, patients are treated with antidepressant medication and, in many cases, also receive psychotherapy or counseling, although the effectiveness of medication for mild or moderate cases is questionable. Hospitalization may be necessary in cases with associated self-neglect or a significant risk of harm to self or others. A minority are treated with electroconvulsive therapy (ECT), under a short-acting general anesthetic. The course of the disorder varies widely, from one episode lasting weeks to a lifelong disorder with recurrent major depressive episodes. Depressed individuals have shorter life expectancies than those without depression, in part because of greater susceptibility to medical illnesses and suicide. It is unclear whether or not medications affect the risk of suicide. Current and former patients may be stigmatized.The understanding of the nature and causes of depression has evolved over the centuries, though this understanding is incomplete and has left many aspects of depression as the subject of discussion and research. Proposed causes include psychological, psycho-social, hereditary, evolutionary and biological factors. Certain types of long-term drug use can both cause and worsen depressive symptoms. Psychological treatments are based on theories of personality, interpersonal communication, and learning. Most biological theories focus on the monoamine chemicals serotonin, norepinephrine and dopamine, which are naturally present in the brain and assist communication between nerve cells.

Schizophrenia (/ˌskɪtsɵˈfrɛniə/ or /ˌskɪtsɵˈfriːniə/) is a mental disorder characterized by a breakdown of thought processes and by poor emotional responsiveness.[1] It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social or occupational dysfunction. The onset of symptoms typically occurs in young adulthood, with a global lifetime prevalence of about 0.3–0.7%.[2] Diagnosis is based on observed behavior and the patient's reported experiences.Genetics, early environment, neurobiology, and psychological and social processes appear to be important contributory factors; some recreational and prescription drugs appear to cause or worsen symptoms. Current research is focused on the role of neurobiology, although no single isolated organic cause has been found. The many possible combinations of symptoms have triggered debate about whether the diagnosis represents a single disorder or a number of discrete syndromes. Despite the etymology of the term from the Greek roots skhizein (σχίζειν, "to split") and phrēn, phren- (φρήν, φρεν-; "mind"), schizophrenia does not imply a "split mind" and it is not the same as dissociative identity disorder—also known as "multiple personality disorder" or "split personality"—a condition with which it is often confused in public perception.[3]

The mainstay of treatment is antipsychotic medication, which primarily suppresses dopamine (and sometimes serotonin) receptor activity. Psychotherapy and vocational and social rehabilitation are also important in treatment. In more serious cases—where there is risk to self and others—involuntary hospitalization may be necessary, although hospital stays are now shorter and less frequent than they once were.[4]

The disorder is thought mainly to affect cognition, but it also usually contributes to chronic problems with behavior and emotion. People with schizophrenia are likely to have additional (comorbid) conditions, including major depression and anxiety disorders; the lifetime occurrence of substance abuse is almost 50%.[5] Social problems, such as long-term unemployment, poverty and homelessness, are common. The average life expectancy of people with the disorder is 12 to 15 years less than those without, the result of increased physical health problems and a higher suicide rate (about 5%).

Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM IV-TR), defines antisocial personality disorder (in Axis II Cluster B) as:[1]

A) There is a pervasive pattern of disregard for and violation of the rights of others occurring since age 15 years, as indicated by three or more of the following:

1.failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are grounds for arrest; 2.deception, as indicated by repeatedly lying, use of aliases, or conning others for personal profit or pleasure; 3.impulsiveness or failure to plan ahead; 4.irritability and aggressiveness, as indicated by repeated physical fights or assaults; 5.reckless disregard for safety of self or others; 6.consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations; 7.lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another;

1% from females, as stated in the DSM IV-TR.

B) The individual is at least age 18 years.C) There is evidence of conduct disorder with onset before age 16 years.D) The occurrence of antisocial behavior is not exclusively during the course of schizophrenia or a manic episode.

New evidence points to the possibility that children often develop antisocial personality disorder as a result of environmental as well as genetic influence. The individual must be at least 18 years of age to be diagnosed with this disorder (Criterion B), but those commonly diagnosed with ASPD as adults were diagnosed with conduct disorder as children. The prevalence of this disorder is 3% in males and

Generalized anxiety disorderMain article: Generalized anxiety disorderGeneralized anxiety disorder (GAD) is a common chronic disorder characterized by long-lasting anxiety that is not focused on any one object or situation. Those suffering from generalized anxiety experience non-specific persistent fear and worry and become overly concerned with everyday matters. Generalized anxiety disorder is the most common anxiety disorder to affect older adults.[5] Anxiety can be a symptom of a medical or substance abuse problem, and medical professionals must be aware of this. A diagnosis of GAD is made when a person has been excessively worried about an everyday problem for six months or more.[6] A person may find they have problems making daily decisions and remembering commitments as a result of lack of concentration/preoccupation with worry.[7] Appearance looks strained, skin is pale with increased sweating from the hands, feet and axillae. May be tearful which can suggest depression.[8] Before a diagnosis of anxiety disorder is made, nurses and physicians must rule out drug-induced anxiety and medical causes.[9]

[edit] Panic disorderMain article: Panic disorderIn panic disorder, a person suffers from brief attacks of intense terror and apprehension, often marked by trembling, shaking, confusion, dizziness, nausea, difficulty breathing. These panic attacks, defined by the APA as fear or discomfort that abruptly arises and peaks in less than ten minutes, can last for several hours and can be triggered by stress, fear, or even exercise; the specific cause is not always apparent.In addition to recurrent unexpected panic attacks, a diagnosis of panic disorder requires that said attacks have chronic consequences: either worry over the attacks' potential implications, persistent fear of future attacks, or significant changes in behavior related to the attacks. Accordingly, those suffering from panic disorder experience symptoms even outside specific panic episodes. Often, normal changes in heartbeat are noticed by a panic sufferer, leading them to think something is wrong with their heart or they are about to have another panic attack. In some cases, a heightened awareness (hypervigilance) of body functioning occurs during panic attacks, wherein any perceived physiological change is interpreted as a possible life-threatening illness (i.e., extreme hypochondriasis).[edit] Panic disorder with agoraphobiaA person experiences an unexpected panic attack, then has substantial anxiety over the possibility of having another attack. The person fears and avoids whatever situation might induce a panic attack. The person may never or rarely leave their home to prevent a panic attack they believe to be inescapable, extreme terror.

[edit] PhobiasMain article: PhobiaThe single largest category of anxiety disorders is that of phobic disorders, which includes all cases in which fear and anxiety is triggered by a specific stimulus or situation. Between 5% and 12% of the population worldwide suffer from phobic disorders.[6] Sufferers typically anticipate terrifying consequences from encountering the object of their fear, which can be anything from an animal to a location to a bodily fluid to a particular situation. Sufferers understand that their fear is not proportional to the actual potential danger but still are overwhelmed by the fear.[10]

[edit] AgoraphobiaMain article: AgoraphobiaAgoraphobia is the specific anxiety about being in a place or situation where escape is difficult or embarrassing or where help may be unavailable.[11] Agoraphobia is strongly linked with panic disorder and is often precipitated by the fear of having a panic attack. A common manifestation involves needing to be in constant view of a door or other escape route. In addition to the fears themselves, the term agoraphobia is often used to refer to avoidance behaviors that sufferers often develop. For example, following a panic attack while driving, someone suffering from agoraphobia may develop anxiety over driving and will therefore avoid driving. These avoidance behaviors can often have serious consequences; in severe cases, one can be confined to one's home.[edit] Social anxiety disorderMain article: Social anxiety disorderSocial anxiety disorder (SAD; also known as social phobia) describes an intense fear and avoidance of negative public scrutiny, public embarrassment, humiliation, or social interaction. This fear can be specific to particular social situations (such as public speaking) or, more typically, is experienced in most (or all) social interactions. Social anxiety often manifests specific physical symptoms, including blushing, sweating, and difficulty speaking. Like with all phobic disorders, those suffering from social anxiety often will attempt to avoid the source of their anxiety; in the case of social anxiety this is particularly problematic, and in severe cases can lead to complete social isolation.