Diagnosis 2.0 Are Mental Illnesses Diseases, Disorders, or Syndromes? A Major Challenge for the DSM-V Committees as They Revise the Diagnostic "Bible" of Psychiatric Disorders Is to Determine Whether Mental Illnesses Are Diseases, Disorders, or Syndromes

Article excerpt

Here's how my version of Webster's dictionary defines these terms:

* Disease: A particular distinctive process in the body with a specific cause and characteristic symptoms.

* Disorder: Irregularity, disturbance, or interruption of normal functions.

* Syndrome: A number of symptoms occurring together and characterizing a specific disease.

Let's consider 4 facts that may be relevant for this decision.

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Probably not 'diseases'

No objective laboratory test can differentiate 1 psychiatric malady from another, and this lack of specificity casts doubt on the disease model. However, many documented perturbations of normal brain functions are consistent with a disorder paradigm.

Symptom overlap

The signs and symptoms of psychiatric ailments overlap considerably. Depression and anxiety share many symptoms and frequently co-occur. Bipolar mania and schizophrenia share psychotic features, cognitive deficits, agitation, suicidality, aggressive behavior, etc. The obsessions of obsessive-compulsive disorder (OCD) resemble and sometimes morph into the fixed false beliefs (delusions) of psychosis, and OCD's compulsions often characterize the behaviors of other psychiatric disorders, such as anorexia or bulimia nervosa.

Personality disorder features essentially are attenuated but enduring forms of Axis I conditions. Nearly all psychiatric illnesses have some degree of suicidality, insomnia, and addictive behavior. Posttraumatic stress disorder's symptoms recapitulate those of numerous diagnostic categories, such as anxiety, depression, psychosis, negative symptoms, mania, OCD, impulsive behavior, and personality changes.

Common neurobiology

Most diagnostic categories in psychiatry share some neurobiologic features, such as:

* neurotransmitter pathways (serotonin, dopamine, norepinephrine, or glutamate)

* structural abnormalities on neuroimaging (cortical atrophy, ventriculomegaly, gray and/or white matter abnormalities) or

* genetic predispositions.

Medical and psychiatric comorbidities (migraine, chronic pain, diabetes, obesity, alcohol abuse, anxiety, eating disorders, and Axis II features) occur across all major psychiatric diagnoses.

Nonspecific medications

Psychotropics approved for treating 1 condition are frequently useful for others:

* Selective serotonin reuptake inhibitors initially were indicated for depression but soon were found to have efficacy for panic attacks, social phobia, OCD, bulimia, impulse dyscontrol, and fibromyalgia. …