Many people believe that chemical imbalances cause mental illnesses, despite the absence of evidence to ascertain this. This study describes the reasoning that people use in their own case to justify this belief. Data come from recorded medication histories with 22 adults aged 23-68 years, taking different psychiatric drugs for various problems and varying durations, asked directly if they thought their problem was caused by a chemical imbalance and to explain their answer. About two-thirds expressed belief that they had a chemical imbalance; and the rest that they did not have one, did not or could not know, or that their medication had caused one. Reasoning backward from positive drug experiences (ex juvantibus or post hoc) and appeals to authority and convention characterized most answers expressing belief in an imbalance. Experiencing improvement while taking drugs and acquiescing in mental health practitioners' views instills or reinforces people's belief that they are or were chemically imbalanced, which suggests viewing the belief as a drug effect. The chemical imbalance notion is likely to persist, as its appeal to give personal meaning to symptom relief and its unfalsifiability ensure institutional support that neutralizes the absence of scientific support.
Keywords: illness and healing narratives; chemical imbalance; informal reasoning; psychoactive drugs
The notion of chemical imbalance encapsulates lay and professional conceptions of the mechanism of mental illness at least since the advent of Prozac and the decade of the brain in the late 1980s. Denoting a causal neurochemical substrate to distressed or unwanted feelings or behavior, the notion has been promoted in peer-reviewed articles, textbooks, direct-to-consumer-advertisements for psychiatric drugs, media, firstperson accounts of psychological distress, and popular discourse. One survey found that up to "75 percent of consumers believe that mental illnesses are usually caused by a chemical imbalance in the brain" (American Psychiatric Association [APA], 2005, p. 1). Another survey found the belief to be espoused more often by White than African American adults (Schnittker, Freese, & Powell, 2000).
People who believe they have a chemical imbalance are more likely to accept and adhere to a drug treatment (Aikens, Nease, & Klinkman, 2008; Johnson et al., 2000; Manber et al., 2003). A therapist writes, "A day does not goes by that a client does not tell me that they have been told by their 'doctor' that they have a diagnosis and a 'chemical imbalance' and need to be on drugs" (Garcia, 2005, p. 129). After his recovery from psychosis and hospitalization, a mental health peer specialist describes the following transformation, which led to his acceptance of drug treatment:
As I grew to understand the medical model of bipolar disorder, I was able to overcome the stigma associated with my illness and to redefine my person as it relates to my illness. I found out that the chemicals that shoot forth from my neurotransmitters are imbalanced. . . . I am a whole, functioning person with defective neurotransmitters . . . I was emphatic about the fact that . . . I require medicine to make [my] brain chemicals work right. (Fekete, 2004, p. 191)
Many authors have critiqued the chemical imbalance notion as simplistic, reductionist, or unsupported by any critically appraised evidence, but therein may lie precisely its value in marketing psychiatric drugs (Leo & Lacasse 2008). Nearly 90% of 237 students in a convenience sample had seen or heard the chemical imbalance explanation via television (France, Lysaker, & Robinson, 2007). As part of a biological model of distress and misbehavior, its weighty public policy implications include broadened rationales for forced treatment, attractiveness and utility to managed care despite the absence of returns, and the use of medical necessity criteria to allocate treatment (Olsen, 2000). …