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What are Disorders and How do you Diagnose them?

Mental Health Disorders

Mental health disorders (also referred to as conditions or illnesses) are conditions that affect thinking, feeling, mood and behavior causing an impact on a person's ability to function. Any person can be affected by some type of mental illness regardless of age, race, economic status, or overall health. According to the American Psychiatric Association, 1 in 5 US adults have some sort of mental illness and 1 in 24 has a serious mental illness.

Some qualifiers of mental illness diagnoses include:

  • Affect on daily functioning

  • Significant changes in thinking, emotion, and/or behavior

  • Significant distress

  • meets criteria specified in the most recent Diagnostic and Statistical Manual of Mental Disorders (as of 2019, the most recent is the 5th edition - DSM5)

Disorder Categories

The DSM separates Mental Disorders into three broad categories:

  • Adult

  • Childhood

  • Personality

  • Other

The DSM also lists the disorders in order of their criteria and codes according to 20 Categories:

  • Neurodevelopmental Disorders

  • Schizophrenia Spectrum (and other Psychotic Disorders)

  • Bipolar and Related Disorders

  • Depressive Disorders

  • Anxiety Disorders

  • Obsessive-Compulsive (and related Disorders)

  • Trauma- and Stressor-Related Disorders

  • Somatic Symptoms (and related Disorders)

  • Feeding and Eating Disorders

  • Elimination Disorders

  • Sleep and Wake Disorders

  • Sexual Dysfunctions

  • Gender Dysphoria

  • Disruptive, Impulse-Control, and Conduct Disorders

  • Addictive Disorders

  • Neurocognitive Disorders

  • Personality Disorders

  • Paraphilic Disorders

  • Other Mental Disorders

  • Medication-Induced Movement Disorders (or other effects of medication)

For the purposes of my research and my own diagnoses, I separate the disorders a bit differently based on symptom type/presentation.

The following are my own eleven categories of diagnoses:

  • Anxiety Disorders

  • Conduct Disorders

  • Dissociative Disorders

  • Mood Disorders

  • Eating and Feeding Disorders

  • Cognitive/Developmental Disorders

  • Personality Disorders

  • Trauma Disorders

  • Sexual Disorders

  • Sleep Disorders

  • Other Disorders (and conditions)


The DSM lists each disorder with it's specific criteria followed by features and specifiers, prevalence, risks and prognoses, cultural factors/issues, differential diagnoses, and co-morbidity. More or less information may be included depending on the disorder.


Criteria is basically a list of requirements to be diagnosed with a disorder. This typically includes duration (how long the symptoms have to be ongoing), onset (when the symptoms have to have occurred), and symptoms.

For example, here are the criteria for Major Depressive Disorder:

  • Five (or more) of the following symptoms have been present during the same 2-week period and represent a change from previous functioning; at least one of the symptoms is either (1) depressed mood or (2) loss of interest or pleasure.

  • *Note: Do not include symptoms that are clearly attributable to another medical condition. Depressed most of the day, nearly every day as indicated by subjective report (e.g., feels sad, empty, hopeless) or observation made by others (e.g., appears tearful)

  • Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day (as indicated by subjective account or observation)

  • Significant weight loss when not dieting or weight gain (e.g., change of more than 5% of body weight in a month), or decrease or increase in appetite nearly every day Insomnia or hypersomnia nearly every day

  • Psychomotor agitation or retardation nearly every day (observable by others, not merely subjective feelings of restlessness or being slowed down)

  • Fatigue or loss of energy nearly every day

  • Feelings of worthlessness or excessive or inappropriate guilt (which may be delusional) nearly every day (not merely self-reproach or guilt about being sick).

  • Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by subjective account or as observed by others)

  • Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide

  • *The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

  • *The episode is not attributable to the physiological effects of a substance or to another medical condition.

  • * Note: The above criteria represent a major depressive episode.

  • *The occurrence of the major depressive episode is not better explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, or other specified and unspecified schizophrenia spectrum and other psychotic disorders.

  • *There has never been a manic episode or a hypomanic episode.


Within the criteria, the subtypes and specifiers of the diagnosis are listed. These typically consist of terms such as "mild, moderate, severe, and profound" or for subtypes they may include . Occasionally, specific features will also be listed and they explain the type of symptoms associated with the diagnoses that may or may not be present.

For example: the diagnosis Specific Phobia has specifiers of features including:

  • Animal

  • Natural environmental

  • Blood-injection-injury

  • Situational

  • Other

The first thing listed after criteria is diagnostic features. This paragraph or section of pages explains the criteria in more detail and specifies modes of assessment along with statistical facts regarding the criteria. Then, associated features explains symptoms that may be relevant to the diagnosis even if they are not part of the criteria.


The prevalence section explains the statistical data associated with the disorder.

For example, Dissociative Identity Disorder (DID) states that the 12 month prevalence of DID in the US according to a small study was 1.5%. For males it was 1.6% and for females 1.4%.


The next section explores the risk of developing the specified disorder based on different factors. Typically these factors include environmental and genetic/physiological.

For example, listed risk factors for Delirium include the following:

  • Environmental: Risk may be increased by immobility, history of falls, low levels of activity, or drug use.

  • Genetic/Physiological: Risk may be increased by older age, infancy/childhood, and febrile illnesses as well as certain medication use.

Cultural Issues

Both "culture" and "gender" are mentioned and both discuss the issues associated with cultural/gender differences that may affect diagnosis as well as the prevalence based on gender and culture.

For example, Histrionic Personality Disorder lists norms or interpersonal behavior such as emotionality, seductiveness, and charm and how they vary widely across cultures, genders, and age groups. It also mentions that Histrionic is more prevalent with females, but that this may be in-congruent with multiple studies and could be caused by gender bias and mis/under-diagnoses.


This section mentions disorders that could be confused with/mis-diagnosed for the disorder being explained along with differences between the disorders to assist with differentiation.

For example, the listed differentials for Alcohol Use Disorder are as follows:

  • Non-pathological use of alcohol - Use does not meet criteria and is not in "excess".

  • Sedative, hypnotic, or anxiolytic use disorder - signs are similar, but use is different.

  • Conduct disorder (childhood) Antisocial Personality Disorder (adult) - can be co-morbid, but AUD does not meet criteria for conduct/Antisocial.


This section explains the different disorders that are likely to be (or proven to be) co-morbid with the original disorder. This can help you to determine a diagnosis more easily if the person already has one of the co-morbid disorders.

For example, Schizophrenia is co-morbid with Panic Disorder, PTSD, and OCD meaning that it is more prevalent in those who are already diagnosed with one of the mentioned disorders.

Over the next few weeks, we will be going over the criteria and the symptoms and signs that could lead one to a diagnosis of all of the different disorders that are listed in the DSM-5. Next week, we will start with intake and figure out how to determine the primary problem!

Questions? Comments? Comment below or email me at



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