The relationship between schizoid personality disorder (SzPD) and avoidant personality disorder (AvPD) has been a subject of controversy for decades. [1] [2]
Today it is still unclear and remains to be seen if these two personality disorders are genuinely distinct, but overlapping, personality disorders, or if they are merely two different phenotypic expressions of the same underlying disorder. Both have been associated with a shared genetic risk factor and the same polymorphism within the ANKK1 gene. [3] [4] There is also some evidence that AvPD (like SzPD) is a personality disorder of the schizophrenia spectrum. [5]
Originally, schizoid personality disorder involved social avoidance combined with marked ambivalence regarding the desirability of social contact. It included indifference or even cold disdain oscillating with longing for normal relationships. Through the efforts of Theodore Millon, this complex idea was later divided across two disorders with the emergence of a separate AvPD construct and the idea of ambivalence was lost. [6]
According to the differential diagnosis guidelines provided in the text of the DSM-IV the two conditions are distinguished by the extent to which the individual desires social contact versus being indifferent to it. But such distinctions are often difficult to apply in practice, as patients often have unclear, marginal, or shifting status on those elements thought most crucial for differential diagnosis. In the case of the avoidant and schizoid PDs, however, both the problem and its solution may be more academic than real. First, research indicates that all of the avoidant symptoms except social withdrawal correlate negatively with the schizoid symptom list and that differential diagnosis is not difficult. [7] Second, as pointed out by Benjamin (1993), schizoid PD is exceedingly rare and the diagnostic quandary may never occur in practice. [6]
However, new research shows that both PDs are linked to hypersensitivity. [8]
Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior that is inappropriate for a given situation. There may also be sleep problems, social withdrawal, lack of motivation, and difficulties carrying out daily activities. Psychosis can have serious adverse outcomes.
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations, delusions, and disorganized thinking. Other symptoms include social withdrawal, and flat affect. Symptoms typically develop gradually, begin during young adulthood, and in many cases never become resolved. There is no objective diagnostic test; diagnosis is based on observed behavior, a psychiatric history that includes the person's reported experiences, and reports of others familiar with the person. To be diagnosed with schizophrenia, the described symptoms need to have been present for at least six months or one month. Many people with schizophrenia have other mental disorders, especially substance use disorders, depressive disorders, anxiety disorders, and obsessive–compulsive disorder.
Borderline personality disorder (BPD), also known as emotionally unstable personality disorder (EUPD), is a personality disorder characterized by a long-term pattern of intense and unstable interpersonal relationships, distorted sense of self, and strong emotional reactions. Those affected often engage in self-harm and other dangerous behaviors, often due to their difficulty with returning their emotional level to a healthy or normal baseline. They may also struggle with a feeling of emptiness, fear of abandonment, and dissociation.
Schizoid personality disorder is a personality disorder characterized by a lack of interest in social relationships, a tendency toward a solitary or sheltered lifestyle, secretiveness, emotional coldness, detachment, and apathy. Affected individuals may be unable to form intimate attachments to others and simultaneously possess a rich and elaborate but exclusively internal fantasy world. Other associated features include stilted speech, a lack of deriving enjoyment from most activities, feeling as though one is an "observer" rather than a participant in life, an inability to tolerate emotional expectations of others, apparent indifference when praised or criticized, a degree of asexuality, and idiosyncratic moral or political beliefs.
Schizoaffective disorder is a mental disorder characterized by abnormal thought processes and an unstable mood. This diagnosis requires symptoms of both schizophrenia and a mood disorder: either bipolar disorder or depression. The main criterion is the presence of psychotic symptoms for at least two weeks without any mood symptoms. Schizoaffective disorder can often be misdiagnosed when the correct diagnosis may be psychotic depression, bipolar I disorder, schizophreniform disorder, or schizophrenia. This is a problem as treatment and prognosis differ greatly for most of these diagnoses.
Avoidant personality disorder (AvPD) or Anxious personality disorder is a Cluster C personality disorder characterized by excessive social anxiety and inhibition, fear of intimacy, severe feelings of inadequacy and inferiority, and an overreliance on avoidance of feared stimuli as a maladaptive coping method. Those affected typically display a pattern of extreme sensitivity to negative evaluation and rejection, a belief that one is socially inept or personally unappealing to others, and avoidance of social interaction despite a strong desire for it. It appears to affect an approximately equal number of men and women.
Schizotypal personality disorder, also known as schizotypal disorder, is a cluster A personality disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM) classification describes the disorder specifically as a personality disorder characterized by thought disorder, paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs. People with this disorder feel pronounced discomfort in forming and maintaining social connections with other people, primarily due to the belief that other people harbor negative thoughts and views about them. Peculiar speech mannerisms and socially unexpected modes of dress are also characteristic. Schizotypal people may react oddly in conversations, not respond, or talk to themselves. They frequently interpret situations as being strange or having unusual meanings for them; paranormal and superstitious beliefs are common. Schizotypal people usually disagree with the suggestion that their thoughts and behaviors are a 'disorder' and seek medical attention for depression or anxiety instead. Schizotypal personality disorder occurs in approximately 3% of the general population and is more commonly diagnosed in males.
Catechol-O-methyltransferase is one of several enzymes that degrade catecholamines, catecholestrogens, and various drugs and substances having a catechol structure. In humans, catechol-O-methyltransferase protein is encoded by the COMT gene. Two isoforms of COMT are produced: the soluble short form (S-COMT) and the membrane bound long form (MB-COMT). As the regulation of catecholamines is impaired in a number of medical conditions, several pharmaceutical drugs target COMT to alter its activity and therefore the availability of catecholamines. COMT was first discovered by the biochemist Julius Axelrod in 1957.
In psychology, schizotypy is a theoretical concept that posits a continuum of personality characteristics and experiences, ranging from normal dissociative, imaginative states to extreme states of mind related to psychosis, especially schizophrenia. The continuum of personality proposed in schizotypy is in contrast to a categorical view of psychosis, wherein psychosis is considered a particular state of mind, which the person either has or does not have.
Paranoid personality disorder (PPD) is a mental illness characterized by paranoia, and a pervasive, long-standing suspiciousness and generalized mistrust of others. People with this personality disorder may be hypersensitive, easily insulted, and habitually relate to the world by vigilant scanning of the environment for clues or suggestions that may validate their fears or biases. They are eager observers and they often think they are in danger and look for signs and threats of that danger, potentially not appreciating other interpretations or evidence.
The dopamine receptor D4 is a dopamine D2-like G protein-coupled receptor encoded by the DRD4 gene on chromosome 11 at 11p15.5.
A spectrum disorder is a mental disorder that includes a range of linked conditions, sometimes also extending to include singular symptoms and traits. The different elements of a spectrum either have a similar appearance or are thought to be caused by the same underlying mechanism. In either case, a spectrum approach is taken because there appears to be "not a unitary disorder but rather a syndrome composed of subgroups". The spectrum may represent a range of severity, comprising relatively "severe" mental disorders through to relatively "mild and nonclinical deficits".
In genetics, rs1800955 is a single nucleotide polymorphism (SNP). It is located in the promoter region of the DRD4 gene. This gene codes for the dopamine receptor D4.
Personality disorders (PD) are a class of mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by the individual's culture. These patterns develop early, are inflexible, and are associated with significant distress or disability. The definitions vary by source and remain a matter of controversy. Official criteria for diagnosing personality disorders are listed in the sixth chapter of the International Classification of Diseases (ICD) and in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM).
Asociality refers to the lack of motivation to engage in social interaction, or a preference for solitary activities. Asociality may be associated with avolition, but it can, moreover, be a manifestation of limited opportunities for social relations. Developmental psychologists use the synonyms nonsocial, unsocial, and social uninterest. Asociality is distinct from, but not mutually exclusive to, anti-social behavior. A degree of asociality is routinely observed in introverts, while extreme asociality is observed in people with a variety of clinical conditions.
Childhood schizophrenia is similar in characteristics of schizophrenia that develops at a later age, but has an onset before the age of 13 years, and is more difficult to diagnose. Schizophrenia is characterized by positive symptoms that can include hallucinations, delusions, and disorganized speech; negative symptoms, such as blunted affect and avolition and apathy, and a number of cognitive impairments. Differential diagnosis is problematic since several other neurodevelopmental disorders, including autism spectrum disorder, language disorder, and attention deficit hyperactivity disorder, also have signs and symptoms similar to childhood-onset schizophrenia.
The diagnosis of schizophrenia, a psychotic disorder, is based on criteria in either the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, or the World Health Organization's International Classification of Diseases (ICD). Clinical assessment of schizophrenia is carried out by a mental health professional based on observed behavior, reported experiences, and reports of others familiar with the person. Diagnosis is usually made by a psychiatrist. Associated symptoms occur along a continuum in the population and must reach a certain severity and level of impairment before a diagnosis is made. Schizophrenia has a prevalence rate of 0.3-0.7% in the United States
Ankyrin repeat and kinase domain containing 1 (ANKK1) also known as protein kinase PKK2 or sugen kinase 288 (SgK288) is an enzyme that in humans is encoded by the ANKK1 gene. The ANKK1 is a member of an extensive family of the Ser/Thr protein kinase family, and protein kinase superfamily involved in signal transduction pathways.
The C957T gene polymorphism is a synonymous mutation located within the 957th base pair of the DRD2 gene. This base pair is located in exon 7. Most synonymous mutations are silent. However, the C957T mutation is an exception to this rule. While the 957C allele codes for the same polypeptide as the 957T allele, the conformation of 957T messenger RNA differs from the conformation of 957C messenger RNA. 957T messenger RNA is less stable and more prone to degradation. Dopamine D2 receptor expression is increased among individuals who carry the 957T allele compared to individuals who carry the 957C allele.
Simple-type schizophrenia is a sub-type of schizophrenia included in the International Classification of Diseases (ICD-10), in which it is classified as a mental and behaviour disorder. It is not included in the current Diagnostic and Statistical Manual of Mental Disorders (DSM-5) or the upcoming ICD-11, effective 1 January 2022. Simple-type schizophrenia is characterized by negative ("deficit") symptoms, such as avolition, apathy, anhedonia, reduced affect display, lack of initiative, lack of motivation, low activity; with absence of hallucinations or delusions of any kind.