Schizophrenia, Psychosis, and Lifespan Development Disorders

DSM-IV-TR Classification Matrix

Schizophrenia and Psychosis — Symptoms

Positive (Type I) symptoms represent excesses or distortions from normal functioning and include the following categories:

Delusions: bizarre and nonbizarre.

Hallucinations: auditory and visual.

Disorganized Speech: loose association, neologisms, clang associations, echolalia/echopraxia, and word salad.

Grossly Disorganized Behavior: catatonic motoric disturbances, including waxy flexibility.

Negative (Type II) symptoms represent the absence or reduction of normal functioning and include: apathy, affective flattening, withdrawal, anhedonia, avolition, poor concentration, poverty of speech, and alogia.

Schizophrenia and Psychosis — Diagnostic Types

Paranoid: characterized by delusions and hallucinations.

Disorganized: characterized by disorganized speech, disorganized behavior, withdrawal, and affective flattening.

Catatonic: characterized by grossly disorganized behavior, disorganized speech, catatonia, echolalia, and echopraxia.

Undifferentiated: active symptoms that do not fit other diagnostic types.

Residual: no Type I symptoms but some negative symptoms present.

Schizoaffective Disorder: Bipolar Type — symptoms of mood disorder and schizophrenia; Depressive Type.

Biological Components

Brief Psychotic Disorder: Type I symptoms lasting less than one month.

Delusional Disorder: Type I symptoms involving nonbizarre delusions.

Shared Delusional Disorder: Type I symptoms involving shared delusions.

Infancy, Childhood, and Adolescence

Mental Retardation: mild, moderate, severe, and profound.

Learning Disorders: reading disorder, mathematics disorder, and disorder of written expression.

Motor Skill Disorders: developmental coordination disorder.

Communication Disorders: expressive language disorder, mixed receptive-expressive language disorder, phonological disorder, and stuttering.

Pervasive Developmental Disorders: autistic disorder, Rett's disorder, childhood disintegrative disorder, and Asperger's disorder.

Attention Deficit and Disruptive Behavior Disorders: attention deficit hyperactivity disorder (ADHD), conduct disorder, and oppositional defiant disorder.

Feeding and Eating Disorders: pica (eating nonfood substances) and rumination disorder (regurgitation).

Emotional Components

Tic Disorders: Tourette's disorder, chronic motor or vocal tic disorder, and transient tic disorder.

Elimination Disorders: encopresis (defecating in inappropriate places) and enuresis (urinating in inappropriate places).

Other Disorders: separation anxiety disorder, selective mutism, reactive attachment disorder, and stereotypic movement disorder.

Old Age

Delirium, Dementia, and Amnestic Disorders: Alzheimer's disease (Hansell & Damour, 2008, pp. 503–504).

Schizophrenia shows a high degree of heritability. Studies have shown that family relatives have a substantially higher risk of developing the disorder than the general population (Tsuang, 2001). The risk of developing schizophrenia in family members increases with the degree of biological relatedness to the patient. "Greater risks are associated with higher levels of shared genes" (Tsuang, 2001, p. 18). First-degree relatives generally share about 50% of their genes and show a risk of approximately 9%, compared to the 1% risk of the general population. The most compelling evidence for genetic linkage comes from monozygotic twins, who show a risk near 50%. While these statistics confirm a genetic connection, they also demonstrate a significant environmental influence on the disease. In particular, for monozygotic twins who share 100% of their genes, the risk of developing schizophrenia is still only 50%.

Schizophrenia is a heterogeneous disorder both clinically and genetically. It encompasses a wide spectrum of related disorders and a varying expression of symptomatology. Genetic studies dismiss the idea that schizophrenia springs from a single gene. Instead, most researchers believe that a multi-factorial polygenic model best describes the genetic composition of the disorder (Tsuang, 2001, p. 19).

The biological components of lifespan development disorders are highly variable, as some are directly associated with a single gene while others show a more indeterminate pattern of inheritance. Mental retardation, for example — one of the fundamental developmental disorders — is most frequently caused by Down syndrome, which has the characteristic trisomy 21 (Hansell & Damour, 2008, p. 506). Learning disorders, by contrast, are less well understood. While there is a clear biological component and familial inheritance of these disorders, the exact genetic composition remains unclear (Hansell & Damour, 2008, p. 509).

The emotional components of schizophrenia and psychosis are largely categorized under negative symptoms — those that are absent or functionally deficient. Studies have specifically identified emotional expression, both facial and vocal, as deficient in schizophrenic patients. "Compared with individuals without schizophrenia, individuals with schizophrenia display fewer positive and negative facial expressions in response to emotionally evocative film clips, foods, and social interactions" (Kring & Moran, 2008, p. 821). This symptom is referred to as affective flattening, a negative Type II symptom denoting the reduction or absence of normal emotional expression. It is very common among schizophrenic patients, who may appear emotionally blunted or express emotions inappropriate to a given situation (Hansell & Damour, 2008, p. 466). Some patients are further debilitated and experience avolition (a lack of motivation) and anhedonia (a lack of pleasure), making it difficult to perform any sort of constructive activity.

Given the wide range of lifespan developmental disorders, emotional components vary substantially. In adults, "emotional distress" is one of the four major criteria for evaluating psychopathology and is a prominent component of adult disorders such as Parkinson's disease and Alzheimer's disease (Hansell & Damour, 2008, p. 500). In children, however, it is more difficult to study emotional components because children and adolescents are often less expressive or communicative. Children with learning disabilities have been shown to suffer emotional harm due to the social exclusion that their disorders can produce. The inability to develop or learn as proficiently as peers has been shown to negatively affect a child's emotional stability (Hansell & Damour, 2008, p. 511). Autism is one lifespan developmental disorder with a particularly pronounced emotional component: children generally lack social or emotional exchange with others and display impaired communication. Conversely, children with attention deficit hyperactivity disorder are often unable to control the expression of their emotions and may be excessively reactive.

Conclusion

The biological, emotional, cognitive, and behavioral components of schizophrenia and psychosis, and lifespan development disorders are extensive and highly variable. This variability makes it especially difficult to categorize and classify specific disorders. As disorders display more overlapping symptoms and comorbid conditions, classification systems are often expanded into a spectrum analysis. This is the case with schizophrenia and psychosis, where Type I and Type II symptoms are grouped together to establish five major diagnostic categories: paranoid, disorganized, catatonic, undifferentiated, and residual. Even these categories, however, do not adequately encapsulate all the different combinations of symptoms that patients present.