A potential psychological disorder must be evaluated in four aspects:

1. Deviance
   The degree in which the behaviour or thoughts are unacceptable in society
2. Distress
   The negative feelings a person has because of the disorder
3. Dysfunction
   The maladaptive behaviour that interferes with properly functioning
4. Danger
   The dangerous or violent behaviour directed towards the self or others.

A person must have clinically significant scores on all these aspects for something to be a psychological disorder. There are three demands to be made to a condition before being labelled a psychological disorder:

1. Internal source
2. Involuntary
3. Clinically significant detriment

The reliability of a diagnostic system refers to the extent to which different diagnosticians, al trained in the use of the system, reach the same conclusion when they independently diagnose the same individuals. The validity of a diagnostic system is an index of the extent to which the categories it identifies are useful and meaningful in clinicians. A label implying a psychological disorder has the potential to interfere with the person’s ability to cope with his or her environment through several means:

1. Potential to stigmatize the diagnosed person
2. Reduce self-esteem diagnosed person
3. Potential to blind clinicians

The medical student’s disease is characterised by a strong tendency to relate personally to and to find in oneself, the symptoms of any disease or disorder described in a textbook. There are several cultural related psychological disorders, such as anorexia nervosa. This used to be a psychological disorder that was only known in western cultures, but because of the globalisation, it happens in other cultures too. Culture does not only affect the types of behaviours and syndromes that people manifest but also affects clinician’s decisions about what to label as disorders, for example, homosexuality used to be labelled as a disorder. There are constantly new disorders being added, one of those is ADHD, which has three varieties:

1. Predominantly inattentive type
   This type is characterised by the lack of attention to instructions and the failure to concentrate.
2. Predominantly hyperactive-impulsive type
   This type is characterised by such behaviours as fidgeting, talking excessively, interrupting others.
3. Combined type
   This type is a combination of the two other types.

One of the most important causes of psychological disorders is brain deficit and the brain itself. Down Syndrome is a disorder that is present at birth and is caused by an error in meiosis, which results in an extra chromosome. Alzheimer’s disease is found primarily in older adults. The disorder is characterised psychologically by a progressive deterioration in all person’s cognitive abilities, followed by deterioration in the brain’s control of bodily functions. The disorder is caused by the presence of amyloid plaques, deposits of a particular protein, called beta-amyloid. There is a difference between chronic disorders and episodic disorders, disorders of which the effects are reversible.

Environmental assaults to the brain, the effects of learning and genes can contribute to the predisposition for episodic disorders. There are three types of causes of psychological disorders:

1. Predisposing causes of psychological disorders
   These are causes that were in place well before the onset of the disorder and make the person susceptible to the disorder (e.g: genetically inherited characteristics, prolonged environmental assaults on the brain and learned beliefs and maladaptive patterns of reacting to or thinking about stressful situations).
2. Precipitating causes of psychological disorders
   These are the immediate events in a person’s life that bring on the disorder, also called major life events.
3. Perpetuating causes of psychological disorders
   These are the consequences of a disorder that help keep it going once it begins (e.g: the negative thought of depression can keep the depression going).

Sex differences in psychological disorders may arise from a number of causes, including the following:

1. Differences in reporting or suppressing psychological stress
2. Clinician’s expectations
3. Differences in stressful experiences
4. Differences in ways of responding to stressful situations

Anxiety disorders are disorders in which fear or anxiety is the most prominent disturbance. The major anxiety disorders are generalized anxiety disorder, phobias and panic disorders. Genetic differences play a considerable role in the predisposition for all these disorders.

People with generalized anxiety disorder worry continuously, about multiple issues, and they experience muscle tension, irritability, and difficulty in sleeping. In order to be diagnosed with generalized anxiety disorder, the life-disrupting worry must occur on more days than not for at least six months and must occur independently of other diagnosable disorders. People with generalized anxiety disorder also have heightened attention to potential threat, called hypervigilance.

A phobia is an intense, irrational fear, that is very clearly related to a particular object or event. Learning plays a role in the causation of phobias. People are genetically prepared to be afraid of some things and not of others. This is why phobias of spiders or snakes are more common than phobias of pigeons. People with phobias tend to avoid the thing they are afraid of and this can perpetuate the disorder.

Panic is a feeling of helpless terror. Panic attacks arise at random moments and cannot be avoided. It is unrelated to a specific object or event. They usually last several minutes. To be diagnosed with a panic disorder, a person must have experienced recurrent unexpected attack, at least one of which is followed by one month of debilitating worry about having another attack or by life-constraining changes in behaviour. A panic disorder often manifests itself after a major life event. A perpetuating cause of the panic disorder is a learned tendency to interpret physiological arousal as panic. Agoraphobia is a fear of public places.

An obsession is a disturbing thought that intrudes repeatedly on a person’s consciousness even though the person recognizes it as irrational. A compulsion is an action following an obsession. People with OCD are people for whom such thoughts and actions are severe, prolonged and disruptive of normal life. To be diagnosed with OCD, the thoughts must consume more than one hour a day and must seriously interfere with work or social relationships. Brain damage can be a predisposing cause of OCD. It may be related to damage to the basal ganglia, portions of the frontal lobe and parts of the underlying limbic system. People with OCD may also have problems with their executive functions.

There are five types of stress disorders:

1. Reactive attachment disorder
   Children with this disorder are inhibited or emotionally withdrawn from their caregivers.
2. Disinhibited social engagement disorder
   Children with this disorder are overly familiar with unfamiliar adults.
3. Acute stress disorder
   Individuals with this disorder experience distressing memories, negative mood, memory loss and sleep disturbances, among other symptoms, for at least three days.
4. Adjustment disorder
   Individuals with this disorder experience emotional distress out of proportion to the severity of the stressor in response to an identifiable event.
5. Posttraumatic stress disorder
   This disorder is necessarily brought on by stressful experiences.

PTSD is characterized by three major symptoms:

1. Uncontrollable re-experiencing
2. Heightened arousal (sleeplessness, irritability, exaggerated startle responses)
3. Avoidance of trauma-related stimuli

People with PTSD show deficits in a number of cognitive abilities, including speed of information processing, working memory, verbal learning and memory, inhibitory control, episodic memory and imagining future events. Genetic predisposition repeated exposures to traumatic events and inadequate social support increase the risk for the disorder.

There are two main categories of mood disorders: depressive disorders and bipolar and related disorders. Depression is characterized primarily by prolonged sadness, self-lame, a sense of worthlessness and absence of pleasure. The total amount of sleep, appetite can also be a symptom, as well as agitated and retarded motor symptoms. Retarded motor symptoms include slower speech and slowed body movements. Agitated symptoms include repetitive, aimless movements. There are two types of depression:

1. Major depression
   Very severe symptoms lasting without remission for at least two weeks.
2. Dysthymia
   Less severe symptoms that last for at least two years.

Generalized anxiety disorder and depression are related and are linked to the same genes. The hopelessness theory states that depression results from a pattern of thinking about negative events that have three characteristics:

1. Assuming that the negative event will have disastrous consequences
2. Assuming that the negative event reflects something negative about the individual
3. Attributing the cause of the negative event to something that is stable and global (e.g: attributing failing a test to one’s stupidity)

People with depression often use the thinking style rumination, which involves repetitively and passively focusing on symptoms of distress and the possible causes and consequences of these symptoms. Rumination does not lead to problem-solving but focusses on one’s problems and negative feelings. A major life event often triggers depression. Depression may be caused by the shrinking of the hippocampus and parts of the prefrontal cortex, which is reversible. Antidepressants contain norepinephrine and serotine and this stimulates the growth of these two brain areas, thus explaining why antidepressants help, but only after prolonged use.

Major depression and dysthymia are sometimes called unipolar disorders because they are characterized by mood changes in only one direction. Bipolar disorders are characterized by mood swings in both directions. There are two varieties of bipolar disorders:

1. Bipolar I disorder
   This is characterized by at least one manic episode, which may or may not be followed up by a depressive episode.
2. Bipolar II disorder
   This is characterized by a less extreme high phase, referred to as hypomania, rather than mania.

The predisposition for bipolar disorders is strongly heritable. Bipolar disorders can usually be controlled with doses of lithium.

People with schizophrenia have difficulty distinguishing reality from imagination. To be diagnosed with schizophrenia, an individual must manifest a serious decline in the ability to work, care for himself and connect socially in others. The person must also manifest, for at least one month, two or more of the following five categories of symptoms:

1. Disorganized thought and speech
   The inability to think in a logical, coherent matter. Problem information is often encoded incorrectly.
2. Delusions
   A false belief held in the face of compelling evidence to the contrary. Delusions may result from a fundamental difficulty in identifying and remembering the original source of ideas or actions.
3. Hallucinations
   False sensory perceptions, hearing or seeing things that aren’t there. The most common hallucinations in schizophrenia are auditory.
4. Disorganized or catatonic behaviour
   Disorganized behaviour and the inability to keep the context in mind and to coordinate actions with it. People with schizophrenia may be unable to generate or follow a coherent plan of action. Catatonic behaviour is behaviour that is unresponsive to the environment. Catatonic stupor is the lack of movements for a prolonged period of time.
5. Negative symptoms
   These symptoms are symptoms that involve a lack of, or reduction in, expected behaviours, thoughts, feelings and drives (e.g: people with schizophrenia might be feeling no hunger at all).

People with schizophrenia appear to suffer from deficits in essentially all the basic processes of attention and memory. Schizophrenia may involve unusual patterns of dopamine activity. Overactivity of dopamine in some part of the brain, such as the basal ganglia, may promote the positive symptoms and underactivity of dopamine in the prefrontal cortex may promote the negative symptoms. Glutamate might also play a role in schizophrenia. People with schizophrenia have larger cerebral ventricles, fluid-filled spaces in the brain. Schizophrenia may also occur because of the decline in grey matter in the brain.

The concordance for the disorder is the percentage of relatives of someone with the disorder have the disorder as well. The more closely related someone is to someone with schizophrenia, the greater the change that that person will develop schizophrenia as well. Prenatal variables, such as malnutrition, can influence the likelihood of developing schizophrenia. There are no cultural differences in the occurrence of schizophrenia, but there are differences in the recovery rate. People with schizophrenia in developing countries tend to recover more often.

A personality disorder is an enduring pattern of behaviour, thoughts and emotions that impairs a person´s sense of self, goals and capacity for empathy and-or intimacy. There are three clusters of personality disorders. Cluster A, “odd” personality disorders:

1. Paranoid personality disorder
   People with this disorder are deeply distrustful of other people and are suspicious of their motives.
2. Schizoid personality disorder
   People with this disorder display little in the way of emotion, either positive or negative and tend to avoid social relationships. They genuinely prefer to be alone.
3. Schizotypal personality disorder
   People with this disorder show extreme discomfort in social situations, often bizarre patterns of thinking and perceiving and behavioural eccentricities.

Cluster B, “dramatic” personality disorders:

1. Antisocial personality disorder
   People with this disorder consistently violate or disregard the rights of others. They are sometimes referred to as sociopaths or psychopath. They frequently lie seem to lack moral conscience.
2. Borderline personality disorder
   People with this disorder are emotionally very unstable and show mood swings. They often show dramatic changes in identity, goals, friends and even sexual orientation.
3. Histrionic personality disorder
   People with this disorder continuously seek to be the centre of attention. They behave as if they’re always on stage.
4. Narcissistic personality disorder
   People with this disorder are even more self-centred than people with a histrionic personality disorder. They seek admiration and often lack empathy.

Cluster C, “Anxious” personality disorders:

1. Avoidant personality disorder
   People with this disorder are excessively shy. They are uncomfortable and inhibited in social situations. They feel inadequate and are extremely sensitive to being evaluated, experiencing a dread of criticism. They have an extreme fear of rejection.
2. Dependent personality disorder
   People with this personality disorder show an extreme need to be car4ed for. They are clingy and fear separation from significant people in their lives, believing they cannot care for themselves.
3. Obsessive-Compulsive personality disorder
   People with this disorder are preoccupied with order and control and are thus inflexible and resist change.