A biomarker is an objective, measurable indicator of a specific biological condition. Its presence or absence allows a doctor to diagnose or rule out a particular illness or condition.  This is why we get blood tests, x-rays or other imaging tests, urinalysis etc.



Comorbid is the terms used to refer to conditions that are present along with the primary condition.  In psychiatry, certain disorders are known to be frequently comorbid to each other because when one is present, the other is often present as well. Generalized anxiety disorder, OCD, oppositional defiant disorder and others are considered typically comorbid to bipolar disorder. The diagnosis could be bipolar disorder with comorbid separation anxiety.



This is a general term used to describe living things that share some known genetically-based trait.


Epidemiology (epidemiological)

Epidemiology is the field of study which looks at the patterns, presence, prevalence and causes /effects of disease within a large population. Epidemiological studies try to answer specific questions about a condition and are often used to inform public healthcare decisions.



The genotype is the genetic make-up of a cell, organism or person. Usually research will focus on parts of the genotype which relate to certain conditions.  The identification of a gene or genes which cause an illness helps propel the research because, not only does it immediately link the research to other information known about that gene, but it also allows future studies to gather a purer sample of the condition for analysis. Identification would also pave the way for an objective diagnostic test for the condition.


Neuroanatomical Model

Neuroanatomy refers to the structures of the central nervous system; the brain, retina and spinal cord. The structures range from cells to large areas. A neuroanatomical model would be a hypothesis of the structures relevant to a particular inquiry.



This is the term used for when something is not in a healthy or normal state and could be considered dysfunctional or diseased.



This is a general term used to describe the observable, outward appearance of something. An organism’s phenotype is the combination of its genetic expression and environmental influences; it’s what it looks like from the outside.

In psychiatric research, phenotypes are defined by common behaviors or symptoms.  If you find it uncomfortable to think in terms of “phenotypes”, you can substitute in your mind words like “profile” or “group”.

It is possible that the characteristics chosen to define a phenotype may belong together observationally, but are not meaningful, or not meaningful enough, to point the investigator to the underlying biology that he/she is hoping to discover.



This is the study of how parts within the body function. It includes both chemical and physical processes. 


Stimulus (plural: stimuli)

This is something that provokes or triggers a response. The response could be a function or a behavior.



This is a more specific group of a phenotype.  For instance, you could say all dogs with pronounced snouts and long hair represent a phenotype.  A subtype of that phenotype would be dogs with medium long snouts and curly long hair.



A syndrome is a group of symptoms, characteristics and/or behaviors which associate with each other and which together represent a single illness or condition. The presence of one of those features should therefore alert the professional to look for the others.



Things that are tangible are things that are real, capable of being touched. Intangible would be things that are vague and left to the imagination.