Chemical imbalance (mental health)

Chemical imbalance is a controversial lay explanation according to which a chemical imbalance in the brain is said to be the cause of mental illness.

The term is used in consumer literature and websites for psychoactive drugs (e.g., ), and in advertising in the United States after the deregulation of pharmaceutical advertising. It is not used in scientific literature as it does not reflect current knowledge.

It is not clear to what extent neural changes might cause mental illness, and what extent mental illness might cause neural changes.

A criticism of the use of this lay explanation is that explaining mental illness in terms of 'chemical imbalance' implicates a chemical solution. For example, insufficient availability of insulin in type I diabetes is treated with insulin. By analogy, it then appears that the appropriate treatment for insufficient (imbalanced) neurotransmitter levels is a chemical that fixes this balance. However, unlike Type I diabetes, other treatments are available for mental illness, and medication is often most effective when supplemented with other treatments.

'Chemical imbalances'
Changes in levels of neurotransmitters and other neural level phenomena are hypothesised to be the underlying psychopathology for certain mental illnesses, notably clinical depression and schizophrenia.

Clinical depression
In 1965, Joseph Schildkraut hypothesized that depression was associated with low levels of norepinephrine in the brain, and later researchers thought serotonin might be the culprit. Initially, relatively simple changes in the level of these neurotransmitters were thought to be found in individuals with depression. However, advanced findings began to fine tune the more simple explanations. For example, certain drugs used to treat depression were found to change the levels of neurotransmitters for several days, but then return to normal, well before any effect was observed on the depressive episode. Such findings implicate more complex mechanisms, such as changes in neurotransmitter production, transmission, re-uptake, and neural sensitivity. With respect to causality, a number of environmental factors have been suggested.


 * Further information: Causes of depression

Other disorders
In addition to depression, changes in levels of neurotransmitters have also been implicated in anxiety disorders, bipolar disorder (manic depressive disorder), schizophrenia, and Parkinson's disease. As well as changes in serotonin and norepinephrine, dopamine systems have also been considered.

So, while all biology is essentially chemical in nature, rather than being caused by simple chemical imbalances, mental illness is now widely recognized to be caused by complex and, in many cases, as-yet unknown factors. According to Jaelline Jaffe and Jeanne Segal:
 * "The misconception the [drug] commercials foster is that the brain somehow develops a chemical imbalance and the result is depression, occurring in a single directional process. In fact, the relationship between brain chemistry and experience is a two-directional phenomenon: Life experience affects brain chemistry at least as much as brain chemistry affects life experience.  The 'chemical imbalance' hypothesis is not wrong.  It's just not entirely correct."

Use of drugs to 'correct'
Lay explanations, put forward by pharmaceutical companies, suggest that psychiatric drugs work by "correcting" the levels of these neurotransmitters. However, rather than restoring 'normal' levels, these drugs frequently attempt to compensate for changes in sensitivity to or production of neurotransmitters, with newer drugs acting in a relatively isolated part of the brain (although some drugs act on a larger scale).

Another perspective is that drugs, when they work, are providing a non-specific psychological effect that is useful, rather than correcting a chemical imbalance. For example, SSRIs, according to one author, provide a "well whatever" emotional reaction to experiences. Hence their usefulness not only in depression but panic disorder, obsessive compulsive disorder, generalized anxiety disorder, body dysmorphic disorder, social phobias and many other supposedly specific disorders. The common mechanism is a decrease in overwhelming emotions induced by the medication. Indeed research shows that in lab animals SSRIs decrease "stress induced vocalizations" (in normal not chemically imbalanced! guinea pig and rat pups). Stress induced vocalizations are the normal reaction of pups to being removed from their mothers. Similar signs of stress in normal adult animals and their decrease through the use of SSRI's has been demonstrated. It should be noted that one of the problems with SSRIs can be a reduction in emotional responsiveness beyond what can be described as symptoms. In other words what is good about SSRIs is what is bad about them. For an interesting discussion of these issues see "A Reevaluation of the Relationship between Psychiatric Diagnosis and Chemical Imbalances." 

Limitations on the use of medications
Most disorders treated with medication have a hypothesised neural mechanism, but it is important to note that chemical imbalances are not believed to explain all psychiatric differences, nor are medications used to treat all neurological or psychiatric issues.

Diagnostic utility
There are advanced imaging techniques such as Positron Emission Tomography (PET Scans) that can test for biological changes in the brain. Changes in levels of neurotransmitter metabolites are detectable in urine and cerebrospinal fluid and have been associated with certain mental illnesses, but are not sufficiently predictive for successful diagnosis.

Thus, Psychiatric diagnoses are usually made based on algorithmic (DSM-IV) criteria outlined in diagnostic manuals, primarily through reference to the Diagnostic and Statistical Manual of Mental Disorders (DSM). In practice, psychiatric diagnoses rely upon a physician's judgments about a patient's medical history, clinical evaluation of symptoms, and from patient response to psychiatric drugs.

Popular culture and advertising
The chemical imbalance theory, according to critics, is routinely presented as ‘fact’ so often it has become widely accepted as fact, despite having been challenged repeatedly. For example, Pfizer has heavily promoted its antidepressant drug, Zoloft, with ads asserting that mental illness may be due to a chemical imbalance in the brain, and that "Zoloft works to correct this imbalance."

Without mentioning its own name, Eli Lilly urges viewers to seek treatment for depression, and to visit their website, DepressionHurts.com, because "Many researchers believe depression is caused by an imbalance of naturally occurring chemicals, serotonin and norepinephrine, in the brain and the body."

Controversy
Critics contend that psychiatric drugs are not always efficacious, not always safe, and not necessarily a scientifically sound method for improving mental health. The number of different chemicals in the brain and their unknown interactions limit understanding and increase the likelihood of unforeseen complications. Moreover, critics assert, the psychiatric establishment merely assumes patients who are diagnosed with a given mental illness have a neurological basis, even though behavioral checklists, and not actual neurological measurements, are used to reach a diagnosis.

Psychiatric diagnostic practices in the United States have come under criticism for over-reliance upon these behavioral checklists rather than thorough, whole-body medical testing. For example, in a Florida psychiatric hospital study from the 1980s, one hundred patients diagnosed with a mental illness were subsequently given a complete medical exam, after which it was discovered nearly half of the patients’ psychiatric problems were secondary manifestations of an undiagnosed medical problem, such as hypothyroidism mimicking depression. Most, if not all, hospitals in the United States currently require a medical exam be done on all patients admitted to an inpatient psychiatric unit. The author of the study, psychiatrist Mark Gold, remains a strong advocate that addiction and psychiatric disorders are rooted in complex chemical imbalances and that effective treatment is available for most correctly diagnosed psychiatric patients from various drug treatments -- an opinion that he shares with the majority of the medical community.

Even when neurological and neurochemical differences are associated with certain behaviors, the practice of pathologizing these behaviours has been questioned by some activists and people who have been diagnosed with mental illnesses. Because neural mechanisms imply a physiological difference underlying mental illnesses, they appear to justify the use of medication in treatment. Critics argue that the legitimacy given to medication by neural mechanisms can lead to an over-reliance on medication. Similarly, the perceived efficacy of medication as a treatment implies an underlying neural mechanism.

Critics also allege that pharmaceutical companies have a conflict of interest when they fund research into biochemical mechanisms behind mental illness and the efficacy of medication at reducing behavior differences.

Further controversy is engendered by the links between certain critics of psychiatry and the Church of Scientology. While Anti-psychiatry is not equivalent to Scientology, Scientology maintains several organizations like the Citizens Commission on Human Rights which have been outspoken critics of the biological basis of mental illness, sponsoring websites critical of "chemical imbalance". Here also, there may exist a substantial conflict of interest as Scientology advocates and sells an alternative and expensive non-pharmacological treatment known as Dianetics.

Cautionary measures
An important consideration with regard to chemical intervention is the potential for relapsing into depression or other psychiatric conditions when medication is discontinued abruptly or without medical supervision. Aside from malnutrition, the only certain means of creating chemical imbalances in the brain is the use of psychotropic chemicals, a category which includes both legal prescription drugs and illegal drugs like LSD or cocaine. Side effects from psychotropic drugs can be significant. Great care must be taken to prevent severe withdrawal symptoms after using psychotropic drugs. Neuroleptic drugs (typically used in the treatment of schizophrenia) are particularly dangerous to withdraw from quickly. Rebound psychosis is common and can leave a patient more unstable than they were prior to taking the neuroleptic in the first place.

Current neuroscience perspectives

 * Evidence-based medicine
 * Neurochemistry
 * Neuroscience
 * Neurotransmitter

Critical perspectives

 * Anti-psychiatry
 * ICSPP
 * Mindfreedom.org

History

 * History and evolution of the monoamine hypothesis of depression. J Clin Psychiatry. 2000;61 Suppl 6:4-6
 * Healy, D. (1999). The Antidepressant Era. Harvard University Press.

Current neuroscience theories

 * Neurobiology of depression. Neuron. 2002 Mar 28;34(1):13-25.
 * Is mood chemistry? Nat Rev Neurosci. 2005 Mar;6(3):241-6. Implicates change in information processing not 'chemical imbalance'.

Critical views

 * CCHR - Scientology-affiliated Psychiatric Watchdog Speaks Out About Tom Cruise Speaking Out on Antidepressants
 * 23NLPeople.com - 'Ritalin: Role Models in a Bottle, Social Discipline in a Capsule'
 * ETFRC.com - 'There are no "Chemical Imbalances"', Eaton T. Fores Research Center Against Psychiatry
 * PsychForums.com - Online discussion of ETFRC's 'There are no "Chemical Imbalances"'


 * HappinessOnline.org - 'I'm O.K. You're O.K. We're Not O.K. Some psychiatrists want to start treating "relational disorders." Are they nuts?', Walter Kirn, Time (September 16, 2002)
 * Keirsey.com - 'The Great A.D.D. Hoax', David Keirsey
 * MindFreedom.org - 'Debate Between Pfizer, Inc. and MindFreedom continues: Three Rounds, So Far: MindFreedom Calls for Congressional Investigation of Psychiatric Drug Company Undue Influence and Corruption in Federal Agencies'
 * Oikos.org - 'History of the Fraud of Biological Psychiatry', F. Baughman
 * PLoSJournals.org - 'Serotonin and Depression: A Disconnect between the Advertisements and the Scientific Literature', Jeffrey R. Lacasse, Jonathan Leo, Public Library of Science Medicine, vol 2, no 12 (November 8, 2005)
 * StopShrinks.org - 'Logical Errors in Mental Health', Rob Ryley
 * ThomHartmann.com - 'The Gift of ADHD: ADHD and ADD Home Page', Thom Hartmann
 * ZMag.org - 'Psychiatric Medications, Illicit Drugs, & Alcohol', Bruce Levine (2002)
 * Dushkin.com - 'Depression: Beyond Seratonin', Hara Estroff Marano (1999)

Proponent views

 * Anxiety-and-Depression-Solutions.com - 'Understanding Chemical Imbalance: What is a Chemical Imbalance?', Jake Van Der Borne (14 June 2004)
 * BMA-Wellness.com - 'Frequently Asked Questions About Psychiatry and Mental Health', Floyd P. Garrett, MD
 * HelpGuide.org - 'Medications for Treating Depression and Anxiety: Making Informed Choices', Jaelline Jaffe, PhD, Jeanne Segal, PhD
 * MHSource.com 'Ask the Expert: Chemical Imbalance' (February 2001)
 * Zoloft (Sertraline HCl)