Mental disorder
Mental disorder or mental illness is a psychological or behavioral pattern that occurs in an individual and is thought to cause distress or disability that is not expected as part of normal development or culture. The recognition and understanding of mental disorders have changed over time and across cultures. Definitions, assessments, and classifications of mental disorders can vary, but guideline criteria listed in the ICD, DSM and other manuals are widely accepted by mental health professionals. Categories of diagnoses in these schemes may include dissociative disorders, mood disorders, anxiety disorders, psychotic disorders, eating disorders, developmental disorders, personality disorders, and many other categories. In many cases there is no single accepted or consistent cause of mental disorders, although they are often explained in terms of a diathesis-stress model and biopsychosocial model. Mental disorders have been found to be common, with over a third of people in most countries reporting sufficient criteria at some point in their life. Mental health services may be based in hospitals. Mental health professionals diagnose individuals using different methodologies, often relying on case history and interview. Psychotherapy and psychiatric medication are two major treatment options, as well as supportive interventions. Treatment may be involuntary where legislation allows. Several movements campaign for changes to mental health services and attitudes, including the Consumer/Survivor Movement. There are widespread problems with stigma and discrimination.
History
Eight women representing prominent mental diagnoses in the nineteenth century.
Ancient
civilisations described and treated a number of mental disorders. The Greeks
coined terms for melancholy, hysteria and phobia and developed humorism theory.
Psychiatric theories and treatments developed in
Classification
The definition and classification of mental disorder is a key issue for the mental health professions and for users and providers of mental health services. Most international clinical documents use the term "mental disorder" rather than "mental illness". There is no single definition and the inclusion criteria are said to vary depending on the social, legal and political context. In general, however, a mental disorder has been characterized as a clinically significant behavioral or psychological pattern that occurs in an individual and is usually associated with distress, disability or increased risk of suffering. The term "serious mental illness" (SMI) is sometimes used to refer to more severe and long-lasting disorder. A broad definition can cover mental disorder, mental retardation, personality disorder and substance dependence. The phrase "mental health problems" may be used to refer only to milder or more transient issues. There is often a criterion that a condition should not be expected to occur as part of a person's usual culture or religion. Nevertheless, the term "mental" is not necessarily used to imply a distinction between mental (dys)functioning and brain (dys)functioning, or indeed between the brain and the rest of the body.
There are currently two widely established systems that classify mental disorders - Chapter V of the International Classification of Diseases (ICD-10), produced by the World Health Organization (WHO), and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) produced by the American Psychiatric Association (APA). Both list categories of disorder and provide standardized criteria for diagnosis. They have deliberately converged their codes in recent revisions so that the manuals are often broadly comparable, although significant differences remain. Other classification schemes may be in use more locally, for example the Chinese Classification of Mental Disorders. Other manuals may be used by those of alternative theoretical persuasions, for example the Psychodynamic Diagnostic Manual.
Some approaches to classification do not employ distinct categories based on cut-offs separating the abnormal from the normal. They are variously referred to as spectrum, continuum or dimensional systems. There is a significant scientific debate about the relative merits of a categorical or a non-categorical system. There is also significant controversy about the role of science and values in classification schemes, and about the professional, legal and social uses to which they are put.
Disorders
There are many different categories of mental disorder, and many different facets of human behavior and personality that can become disordered.
The state of anxiety or fear can become disordered, so that it is unusually intense or generalized over a prolonged period of time. Commonly recognized categories of anxiety disorders include specific phobia, Generalized anxiety disorder, Social Anxiety Disorder, Panic Disorder, Agoraphobia, Obsessive-Compulsive Disorder, Post-traumatic stress disorder. Relatively long lasting affective states can also become disordered. Mood disorder involving unusually intense and sustained sadness, melancholia or despair is know as Clinical depression (or Major depression), and may more generally be described as Emotional dysregulation. Milder but prolonged depression can be diagnosed as dysthymia. Bipolar disorder involves abnormally "high" or pressured mood states, known as mania or hypomania, alternating with normal or depressed mood. Whether unipolar and bipolar mood phenomena represent distinct categories of disorder, or whether they usually mix and merge together along a dimension or spectrum of mood, is under debate in the scientific literature.
Patterns of belief, language use and perception can become disordered. Psychotic disorders centrally involving this domain include Schizophrenia and Delusional disorder. Schizoaffective disorder is a category used for individuals showing aspects of both schizophrenia and affective disorders. Schizotypy is a category used for individuals showing some of the traits associated with schizophrenia but without meeting cut-off criteria.
The fundamental characteristics of a person that influence his or her cognitions, motivations, and behaviors across situations and time - can be seen as disordered due to being abnormally rigid and maladaptive. Categorical schemes list a number of different personality disorders, such as those classed as eccentric (e.g. Paranoid personality disorder, Schizoid personality disorder, Schizotypal personality disorder), those described as dramatic or emotional (Antisocial personality disorder, Borderline personality disorder, Histrionic personality disorder, Narcissistic personality disorder) or those seen as fear-related (Avoidant personality disorder, Dependent personality disorder, Obsessive-compulsive personality disorder).
There may be an emerging consensus that personality disorders, like personality traits in the normal range, incorporate a mixture of more acute dysfunctional behaviors that resolve in relatively short periods, and maladaptive temperamental traits that are relatively more stable. Non-categorical schemes may rate individuals via a profile across different dimensions of personality that are not seen as cut off from normal personality variation, commonly through schemes based on the Big Five personality traits.
Other disorders may involve other attributes of human functioning. Eating practices can be disordered, at least in relatively rich industrialized areas, with either compulsive over-eating or under-eating or binging. Categories of disorder in this area include Anorexia nervosa, Bulimia nervosa, Exercise Bulimia or Binge eating disorder. Sleep disorders such as Insomnia also exist and can disrupt normal sleep patterns. Sexual and gender identity disorders, such as Dyspareunia or Gender identity disorder or ego-dystonic homosexuality. People who are abnormally unable to resist urges, or impulses, to perform acts that could be harmful to themselves or others, may be classed as having an impulse control disorder, including various kinds of Tic disorders such as Tourette's Syndrome, and disorders such as Kleptomania (stealing) or Pyromania (fire-setting). Substance-use disorders include Substance abuse disorder. Addictive gambling may be classed as a disorder. Inability to sufficiently adjust to life circumstances may be classed as an Adjustment disorder. The category of adjustment disorder is usually reserved for problems beginning within three months of the event or situation and ending within six months after the stressor stops or is eliminated. People who suffer severe disturbances of their self-identity, memory and general awareness of themselves and their surroundings may be classed as having a Dissociative identity disorder, such as Depersonalization disorder or Dissociative Identify Disorder itself (which has also been called multiple personality disorder, or "split personality".). Factitious disorders, such as Munchausen syndrome, also exist where symptoms are experienced and/or reported for personal gain.
Disorders appearing to originate in the body, but thought to be mental, are known as somatoform disorders, including Somatization disorder. There are also disorders of the perception of the body, including Body dysmorphic disorder. Neurasthenia is a category involving somatic complaints as well as fatigue and low spirits/depression, which is officially recognized by the ICD-10 but not by the DSM-IV. Memory or cognitive disorders, such as amnesia or Alzheimer's disease exist.
Some disorders are thought to usually first occur in the context of early childhood development, although they may continue into adulthood. The category of Specific developmental disorder may be used to refer to circumscribed patterns of disorder in particular learning skills, motor skills, or communication skills. Disorders which appear more generalized may be classed as pervasive developmental disorders (PDD) also known as autism spectrum disorders (ASD); these include autism, Asperger's, Rett syndrome, childhood disintegrative disorder and other types of PDD whose exact diagnosis may not be specified. Other disorders mainly or first occurring in childhood include Reactive attachment disorder; Separation Anxiety Disorder; Oppositional Defiant Disorder; Attention Deficit Hyperactivity Disorder.
Other proposed disorders include: Self-defeating personality disorder, Sadistic personality disorder, Passive-aggressive personality disorder, Premenstrual dysphoric disorder, Video game addiction or Internet addiction disorder.
Causes
Numerous factors have been linked to the development of mental disorders. In many cases there is no single accepted or consistent cause currently established. A common view held is that disorders often result from genetic vulnerabilities combining with environmental stressors (Diathesis-stress model). An eclectic or pluralistic mix of models may be used to explain particular disorders. The primary paradigm of contemporary mainstream Western psychiatry is said to be the biopsychosocial (BPS) model - incorporating biological, psychological and social factors - although this may not be applied in practice. Biopsychiatry has tended to follow a biomedical model, focusing on "organic" or "hardware" pathology of the brain. Psychoanalytic theories have been popular but are now less so. Evolutionary psychology may be used as an overall explanatory theory. Attachment theory is another kind of evolutionary-psychological approach sometimes applied in the context for mental disorders. A distinction is sometimes made between a "medical model" or a "social model" of disorder and related disability.
Genetic studies have indicated that genes often play an important role in the development of mental disorders, via developmental pathways interacting with environmental factors. The reliable identification of connections between specific genes and specific categories of disorder has proven more difficult.
Environmental events surrounding pregnancy and birth have also been implicated. Traumatic brain injury may increase the risk of developing certain mental disorders. There have been some tentative inconsistent links found to certain viral infections, to substance misuse, and to general physical health.
Abnormal functioning of neurotransmitter systems has been implicated, including serotonin, norepinephrine, dopamine and glutamate systems. Differences have also been found in the size or activity of certain brains regions in some cases. Psychological mechanisms have also been implicated, such as cognitive and emotional processes, personality, temperament and coping style.
Social influences have been found to be important, including abuse, bullying and other negative or stressful life experiences. The specific risks and pathways to particular disorders are less clear, however. Aspects of the wider community have also been implicated, including employment problems, socioeconomic inequality, lack of social cohesion, problems linked to migration, and features of particular societies and cultures.
Culture
Mental disorders are often distinguished from experiences or behaviors said to be expected or "normal" within a culture. Criteria and concepts employed to achieve this, for example "incomprehensibility" or "bizarre", are ubiquitous but "infested" with ambiguity and subjectivity, especially across cultures. The issue is particularly contentious with regard to religious, spiritual or transpersonal experiences and beliefs, especially given the diversity involved across cultures, and are often not defined as disordered especially if widely shared, despite the fact that many could easily be seen as delusional from a "rational" point of view. There is also a more general overlap and ambiguity between clinical concepts and the realm of morality, and it has been argued that attempts to separate them cannot do so without altering the essence of what it means to be a particular person in society.Cultural processes can affect which behaviors are considered clinically relevant and how they are framed. The DSM has been said to have a Euro-American outlook, such that differing disorders or concepts from other countries or non-mainstream cultures are neglected or misrepresented; while the latter are described as "culture-bound syndromes", Western cultural phenomena are taken as universals. The fact that diagnostic criteria sets are acceptable to or applied reliably across different cultures does not necessarily make the constructs themselves valid within those cultures, as this can be statistically achieved through an entirely illusory diagnostic construct. On the other hand, it is argued that if a diagnostic category is valid then cross-cultural factors are irrelevant, or only affect how symptoms are manifested.
Cultural variation can suggest that the very construct of "mental disorder" is in fact culture-bound. Different societies, cultures, and even persons within a particular culture may disagree as to what constitutes optimal or pathological biological and psychological functioning, and indeed research has demonstrated variation across cultures in the relative importance placed on, for example, happiness, autonomy, or social relationships for pleasure. Likewise, the fact that a behavior pattern is valued, accepted, encouraged, or even statistically normative within a particular culture does not necessarily mean it is conducive to optimal psychological functioning. There may be a tendency to overstate or misinterpret neurophysiological findings and to understate the scientific importance of social-psychological variables, and the cultural and ethnic diversity of individuals is often discounted by researchers and services providers. Rather than indicating a disorder from within, distress and disability may be seen as an indicator of emotional struggle and the need to address social and structural problems and some academics and clinicians have advocated a postmodernist conceptualization of mental distress and wellbeing and "heretical" psychologies centered on alternative cultural and ethnic identities and experiences.
Diagnosis
Many mental health professionals, particularly psychiatrists, seek to diagnose individuals by ascertaining their particular mental disorder. Some professionals, for example some clinical psychologists, may avoid diagnosis in favor of other assessment methods such as formulation of a client's difficulties and circumstances. The majority of mental health problems are actually assessed and treated by family physicians during consultations, who may refer on for more specialist diagnosis in acute or chronic cases. Routine diagnostic practice in mental health services typically involves an interview (which may be referred to as a mental status examination), where judgments are made of the interviewee's appearance and behavior, self-reported symptoms, mental health history, and current life circumstances. The views of relatives or other third parties may be taken into account. A physical examination to check for ill health or the effects of medications or other drugs may be conducted. Psychological testing is sometimes used via paper-and-pen or computerized questionnaires, which may include algorithms based on ticking off standardized diagnostic criteria, and in relatively rare specialist cases neuroimaging tests may be requested, but these methods are more commonly found in research studies than routine clinical practice. Time and budgetary constraints often limit practicing psychiatrists from conducting more thorough diagnostic evaluations. It has been found that most clinicians evaluate patients using an unstructured, open-ended approach, with limited training in evidence-based assessment methods, and that inaccurate diagnosis may be common in routine practice. Comorbidity is very common in psychiatric diagnosis, i.e. the same person given a diagnosis in more than one category of disorder.
Services and treatments
Treatment and support may be provided in psychiatric hospitals, clinics or any of a diverse range of community mental health services. Often an individual may engage in different treatment modalities. Individuals may be treated against their will in some cases. Services in some countries are increasingly based on a Recovery model that supports an individual's personal journey to regain a meaningful life.
Psychotherapy
A major option for many mental disorders is psychotherapy. There are several main types. Cognitive behavioral therapy (CBT) is widely used and is based on modifying the patterns of thought and behavior associated with a particular disorder. Psychoanalysis, addressing underlying psychic conflicts and defenses, has been a dominant school of psychotherapy and is still in use. Systemic therapy or family therapy is sometimes used, addressing a network of significant others as well as an individual. Some psychotherapies are based on a humanistic approach. There are a number of specific therapies used for particular disorders, which may be offshoots or hybrids of the above types. Mental health professionals often employ an eclectic or integrative approach. Much may depend on the therapeutic relationship, and there may be problems with trust, confidentiality and engagement.
Medication
A major option for many mental disorders is psychiatric medication. There are several main groups. Antidepressants are used for the treatment of clinical depression as well as often for anxiety and other disorders. There are a number of antidepressants beginning with the tricylics, moving through a wide variety of drugs that modify various facets of the brain chemistry dealing with intercellular communication. Beta-blockers, developed as a heart medication, is also used as an antidepressant. Anxiolytics are used for anxiety disorders and related problems such as insomnia. Mood stabilizers are used primarily in bipolar disorder. Lithium A (a metal) and Lamictal (an epileptic drug) are notable for treating both mania and depression. The others, mainly targeting mania rather than depression, are a wide variety of epilepsy medications and antipsychotics. Antipsychotics are used for psychotic disorders, notably for positive symptoms in schizophrenia. Stimulants are commonly used, notably for ADHD. Despite the different conventional names of the drug groups, there can be considerable overlap in the kinds of disorders for which they are actually indicated. There may also be off-label use. There can be problems with adverse effects and adherence.
Other
Electroconvulsive therapy (ECT) is sometimes used in severe cases when other interventions for severe intractable depression have failed. Psychosurgery is considered experimental but is advocated by certain neurologists in certain rare cases.
may be used to provide people with the information to understand and manage their problems. Creative therapies are sometimes used, including music therapy, art therapy or drama therapy. Lifestyle adjustments and supportive measures are often used, including peer support, self-help groups for mental health and supported housing or supported employment (including social firms). Some advocate dietary supplements. Many things have been found to help at least some people. A placebo effect may play a role in any intervention.
Prognosis
Prognosis depends on the disorder, the individual and numerous related factors. Some disorders may be transient, while some may last a lifetime in some cases. Some disorders may be very limited in their functional effects, while others may involve substantial disability and support needs. The degree of ability or disability may vary across different life domains. Continued disability has been linked to institutionalization, discrimination and social exclusion as well as to the inherent properties of disorders.
Even those disorders often considered the most serious and intractable have varied courses. Long-term international studies of schizophrenia have found that over a half of individuals recover in terms of symptoms, and around a fifth to a third in terms of symptoms and functioning, with some requiring no medication. At the same time, many have serious difficulties and support needs for many years, although "late" recovery is still possible. The WHO concluded that the findings joined others in "relieving patients, carers and clinicians of the chronicity paradigm which dominated thinking throughout much of the 20th century." Around half of people initially diagnosed with bipolar disorder achieve syndromal recovery (no longer meeting criteria for the diagnosis) within six weeks, and nearly all achieve it within two years, with nearly a half regaining their prior occupational and residential status in that period. However, nearly a half go on to experience a new episode of mania or major depression within the next two years. Functioning has been found to vary, being poor during periods of major depression or mania but otherwise fair to good, and possibly superior during periods of hypomania in Bipolar II.
Despite often being characterized in purely negative terms, some mental states labeled as disorders can also involve above-average creativity, non-conformity, goal-striving, meticulousness, or empathy. In addition, the public perception of the level of disability associated with mental disorders can change.
Prevalence
Mental disorders have been found to be relatively common, with more than one in three people in most countries reporting sufficient criteria for at least one diagnosis at some point in their life up to the time they were assessed. A new WHO global survey currently underway indicates that anxiety disorders are the most common in all but 1 country, followed by mood disorders in all but 2 countries, while substance disorders and impulse-control disorders were consistently less prevalent. Rates varied by region. Such statistics are widely believed to be underestimates, due to poor diagnosis (especially in countries without affordable access to mental health services) and low reporting rates, in part because of the predominant use of self-report data rather than semi-structured instruments.[citation needed] Actual lifetime prevalence rates for mental disorders are estimated to be between 65% and 85%.[citation needed]
A review of anxiety disorder surveys in different countries found average lifetime prevalence estimates of 16.6%, with women having higher rates on average. A review of mood disorder surveys in different countries found lifetime rates of 6.7% for major depressive disorder (higher in some studies, and in women) and 0.8% for bipolar 1 disorder.
The updated US National Comorbidity Survey (NCS) reported that nearly half of Americans (46.4%) meet criteria at some point in their life for either an anxiety disorder (28.8%), mood disorder (20.8%), impulse-control disorder (24.8%) or substance use disorder (14.6%).
A 2004 cross-Europe study found that approximately one in four people reported meeting criteria at some point in their life for at least one of the DSM-IV disorders assessed, which included mood disorders (13.9%), anxiety disorders (13.6%) or alcohol disorder (5.2%). Approximately one in ten met criteria within a 12-month period. Women and younger people of either gender showed more cases of disorder. A 2005 review of surveys in 16 European countries found that 27% of adult Europeans are affected by at least one mental disorder in a 12 month period.
An international review of studies on the prevalence of schizophrenia found an average (median) figure of 0.4% for lifetime prevalence; it was consistently lower in poorer countries.
Studies
of the prevalence of personality disorders (PDs) have been fewer and
smaller-scale, but one broad Norwegian survey found a five-year prevalence of
almost 1 in 7 (13.4%). Rates for specific disorders ranged from 0.8% to 2.8%,
differing across countries, and by gender, educational level and other factors.
A
Approximately 7% of a preschool pediatric sample were given a psychiatric diagnosis in one clinical study, and approximately 10% of 1- and 2-year-olds receiving developmental screening have been assessed as having significant emotional/behavioral problems based on parent and pediatrician reports.
Professions and fields
A number of professions have developed that specialise in the treatment of mental disorders, including the medical speciality of psychiatry (including psychiatric nursing), the division of psychology known as clinical psychology, Social Work, as well as Mental Health Counselors, Marriage and Family Therapists, Psychotherapists, Counselors and Public Health professionals. Those with personal experience of using mental health services are also increasingly involved in researching and delivering mental health services and working as mental health professionals. The different clinical and scientific perspectives draw on diverse fields of research and theory, and different disciplines may favor differing models, explanations and goals.
Movements
The Consumer/Survivor Movement (also known as user/survivor movement) is made up of individuals (and organizations representing them) who are clients of mental health services or who consider themselves "survivors" of mental health services. The movement campaigns for improved mental health services and for more involvement and empowerment within mental health services, policies and wider society. Patient advocacy organizations have expanded with increasing deinstitutionalization in developed countries, working to challenge the stereotypes, stigma and exclusion associated with psychiatric conditions. An antipsychiatry movement fundamentally challenges mainstream psychiatric theory and practice, including the reality or utility of psychiatric diagnoses of mental illnesses.
Laws and policies
Three quarters of countries around the world have mental health legislation. Compulsory admission to mental health facilities (also known as Involuntary commitment or sectioning), is a controversial topic. From some points of view it can impinge on personal liberty and the right to choose, and carry the risk of abuse for political, social and other reasons; from other points of view, it can potentially prevent harm to self and others, and assist some people in attaining their right to healthcare when unable to decide in their own interests.
All
human-rights oriented mental health laws require proof of the presence of a
mental disorder as defined by internationally accepted standards, but the type
and severity of disorder that counts can vary in different jurisdictions. The
two most often utilized grounds for involuntary admission are said to be
serious likelihood of immediate or imminent danger to self or others, and the
need for treatment. Applications for someone to be involuntarily admitted may
usually come from a mental health practitioner, a family member, a close
relative, or a guardian. Human-rights-oriented laws usually stipulate that
independent medical practitioners or other accredited mental health
practitioners must examine the patient separately and that there should be
regular, time-bound review by an independent review body. An individual must be
shown to lack the capacity to give or withhold informed consent (i.e. to
understand treatment information and its implications). Legal challenges in some
areas have resulted in supreme court decisions that a person does NOT have to
agree with a psychiatrist's characterization of their issues as an
"illness", nor with a psychiatrist's conviction in medication, but
only recognise the issues and the information about treatment options. Proxy
consent (also known as substituted decision-making) may be given to a personal
representative, a family member or a legally appointed guardian, or patients
may have been able to enact an advance directive as to how they wish to be
treated. The right to supported decision-making may also be included in
legislation. Involuntary treatment laws are increasingly extended to those
living in the community, for example outpatient commitment laws (known by
different names) are used in
The World Health Organization reports that in many instances national mental health legislation takes away the rights of persons with mental disorders rather than protecting rights, and is often outdated. In 1991, the United Nations adopted the Principles for the Protection of Persons with Mental Illness and the Improvement of Mental Health Care, which established minimum human rights standards of practice in the mental health field. In 2006 the UN formally agreed the Convention on the Rights of Persons with Disabilities to protect and enhance the rights and opportunities of disabled people, including those with psychosocial disabilities
The term insanity, sometimes used colloquially as a synonym for mental illness, is often used technically as a legal term.
Perception and discrimination
Stigma
The
social stigma associated with mental disorders is a widespread problem. Some
people believe those with serious mental illnesses cannot recover, or are to
blame for problems. The
Efforts are being undertaken worldwide to eliminate the stigma of mental illness Their methods and outcomes have sometimes been criticized as counterproductive.
Media and general public
Media coverage of mental illness comprises predominantly negative depictions, for example, of incompetence, violence or criminality, with far less coverage of positive issues such as accomplishments or human rights issues. Such negative depictions, including in children's cartoons, are thought to contribute to stigma and negative attitudes in the public and in those with mental health problems themselves, although more sensitive or serious cinematic portrayals have increased in prevalence.
In
the
The general public have been found to hold a strong stereotype of dangerousness and desire for social distance from individuals described as mentally ill.
Violence
People with mental disorders are often afraid of violence against them. Over a quarter of individuals accessing community mental health services in a US inner-city area are victims of at least one violent crime in a given year, a proportion eleven times higher than the inner-city average. The proportion is many times greater in every category of crime, including rape/sexual assault, other violent assaults, and personal and property theft. Findings consistently indicate that it is many times more likely that people diagnosed with a serious mental illness living in the community will be the victims rather than the perpetrators of violence.
However, fear of unpredictable violent acts by people with mental illness is also common. One US national survey indicated that a far higher percentage of Americans rated individuals described as displaying the characteristics of a mental disorder (for example Schizophrenia or Substance Use Disorder) as "likely to do something violent to others" compared to those described as being 'troubled' Research indicates, on balance, a higher than average number of violent acts by some individuals with certain diagnoses, notably antisocial or psychopathic personality disorders, but conflicting findings about specific symptoms (for example links between psychosis and violence in community settings) - but the mediating factors of such acts are most consistently found to be mainly socio-demographic and socio-economic factors such as being young, male, of lower socio-economic status and, in particular, substance abuse (including alcohol). For the most serious crimes, such as homicide, some diagnoses are over-represented in arrests/convictions; however, although high-profile cases have lead to fears that this has increased due to deinstitutionalization, this does not reflect the evidence.
Violence related to mental disorder typically occurs in the context of complex social interactions, often in a family setting rather than between straingers. It is also an issue in healthcare settings and the wider community.
Mental disorders in non-human animals
Psychopathology in non-human primates has been studied since the mid 20th century. Over 20 behavioral patterns in captive chimpanzees have been documented as (statistically) abnormal for their frequency, severity or oddness - some of which have also been observed in the wild. Captive great apes show gross behavioral abnormalities such as stereotypy of movements, self-mutilation, disturbed emotional reactions (mainly fear or aggression) towards companions, lack of species-typical communications, and generalized learned helplessness. In some cases such behaviors are hypothesized to be equivalent to symptoms associated with psychiatric disorders in humans such as depression, anxiety disorders, eating disorders and post-traumatic stress disorder. Concepts of antisocial, borderline and schizoid personality disorders have also been applied to non-human great apes.
The risk of anthropomorphism is often raised with regard to such comparisons, and assessment of non-human animals cannot incorporate evidence from linguistic communication. However, available evidence may range from nonverbal behaviors - including physiological responses and homologous facial displays and acoustic utterances - to neurochemical studies. It is pointed out that human psychiatric classification is often based on statistical description and judgement of behaviors (especially when speech or language is impaired) and that the use of verbal self-report is itself problematic and unreliable.
Psychopathology has generally been traced, at least in captivity, to adverse rearing conditions such as early separation of infants from mothers; early sensory deprivation; and extended periods of social isolation. Studies have also indicated individual variation in temperament, such as sociability or impulsiveness. Particular causes of problems in captivity have included integration of strangers in to existing groups and a lack of individual space, in which context some pathological behaviors have also been seen as coping mechanisms. Remedial interventions have included careful individually-tailored re-socialization programs, behavior therapy, environment enrichment, and on rare occasions psychiatric drugs. Socialization has been found to work 90% of the time in disturbed chimpanzees, although restoration of functional sexuality and care-giving is often not achieved.
Laboratory researchers sometimes try to induce symptoms in animals through genetic, neurological or behavioral manipulation, although this has been criticized on empirical grounds and opposed on animal rights grounds. The modern city, in connection with the psychological disorders of its residents, has been described as a human zoo.
