Sometimes the feelings that are felt by a clinician -- either in empathy for a person or in "countertransference," where emotions are stirred in the doctor in response to those the patient is feeling -- can be useful, if sometimes imprecise. Some of the most notable moments of this phenomenon surface in the media when a doctor's sexual desires are mobilized in response to his or her patient -- and then acted upon. The feeling activated in the doctor may be diagnostically informative in understanding a patient's internal state but acting on this countertransference is unethical and destructive.
Empathy can also be useful, but it must be managed. I (LIS) recall feeling discouraged after spending time with depressed patients. I had to tell myself that I was not getting depressed but instead feeling what my patient was feeling. In those instances, I had to be sure to not voice the same bleak outlook as my patient since that wasn't true (beyond the moment), nor would it be helpful. Detecting my empathic feelings, importantly, was diagnostic information, and useful. But only if I kept my feelings to myself.
Psychiatrists routinely begin with: "Tell me what brings you here. When did your problems start? And then what happened?" With further inquiry we uncover information about what makes the condition worse or better. Sometimes the information obtained reveals a pretty clear picture. For example, an unrelenting blue mood, guilt, trouble sleeping, loss of appetite, reduced libido, hopelessness, and a wish to end one's life fits the profile of a major depression (duration is another data point, if subjective in nature, with depressive signs and symptoms needing to persist at least two weeks).
At other times, the clinical picture is too vague to tell: loss of energy, wanting to avoid others, trouble concentrating, for example, are worrisome and interfere with functioning but do not sufficiently, or specifically, portray what is going on. But the diagnostic process remains the same: keen observation, active listening, and pattern recognition. This is the great art of medical diagnostics: age-old yet as relevant today as it was when Hippocrates, the Greek father of medicine, was evaluating patients.
What is going on in the doctor's mind is called 'differential diagnosis' -- a systematic process of telling two (or more) conditions apart. This is medical detective work at its finest, and television has capitalized on its intrigue (House having lasted eight seasons). As a patient, you may hear this as "...while you may have depression, it is possible there is a problem with your thyroid or other physical problem, or your heart medicine may have unwelcome side effects that cause low mood and energy...we need to find out more." For general medical conditions the 'more' is typically blood tests and scans; for psychiatry it is more history, observation (by patient, significant others, and clinicians), and time.
For new onset emotional problems, especially those that develop absent a clear psychological stressor, your doctor needs to 'rule out' other conditions. A doctor will want to determine if the symptoms and signs may be caused by a physical illness, side effects of a prescribed medication(s), or by drugs and alcohol used in excess and disrupting the fragile equilibrium of our nervous system. Common examples of medical conditions that can produce emotional problems include hypo- and hyperthyroidism, mononucleosis, autoimmune diseases like systemic lupus and multiple sclerosis, and early stage malignancies. Identifying these physical conditions also requires a careful history, a thorough physical examination, blood tests and sometimes an imaging study or biopsy.
A black mark remains in the history of psychiatry as a consequence of an incomplete differential diagnosis of George Gershwin. At the height of his career, at 36, while beginning to write "Porgy and Bess," the great composer began to suffer depressive symptoms. He entered psychoanalysis but his condition worsened. In time, he began to lose his coordination, have severe headaches and smell unusual odors. He had a brain tumor. He died during a surgical effort to remove the tumor that had grown massively in the two years since his symptoms began. Differential diagnosis can make a difference between life and death, back in the 1930s and still today.
The use or abuse of alcohol, non-prescribed medications, or street drugs often confounds persistent psychiatric symptoms and diagnosis. The person suffering from addiction is frequently impaired in their day-to-day functioning, mood, and thinking. Alcohol abuse can cause depressed feelings as well as disinhibit humans who then are apt to engage in dangerous or troublesome behaviors. Amphetamines of all types, especially methedrine, deplete the brain of essential neurotransmitters and can produce excitement or psychosis. Ecstasy is neurotoxic. Narcotic analgesic pills like OxyCodone™ and Vicodin™ taken abusively produce withdrawal and serious mood problems. The various psychiatric complications of substance use and abuse are called organic mood (or cognitive or psychotic) disorders.
Collateral information, from family, friends, school and others, may be needed to detect a substance abuse disorder that is inducing psychiatric symptoms or aggravating other mental disorders. While blood and urine tests often can detect the presence of these substances, unfortunately brain imaging (e.g. MRIs, EEGs, PET Scans) cannot. Despite two decades of spectacular neuroimaging advances to our understanding of the brain's anatomy, physiology and reward pathways, its use in diagnostic decisions has yet to be integrated into clinical practice. Nor does psychiatry have accurate biological markers to guide a substance abuse diagnosis.
This is not due to lack of trying, but rather the result of how complex the brain is to comprehend. We do know what happens to the brain on drugs: the image of the egg frying on a pan -- from a brilliant ad campaign led by the Partnership for A Drug Free America in the late 1980's that promoted "This is your brain on drugs" -- illustrates the destructive power of drugs even if we cannot reliably demonstrate it on an MRI (until too much brain tissue is gone and it is too late!).
A throat swab with a rapid Strep test quickly diagnoses the absence or presence of an infection ("yes or no") and a bone densitometry [DEXA] scan indicates risk for osteoporosis by comparing the individual's results as compared to a comparable population's. But a diagnosis of addiction is far more complex with genetics and the environment at work and to date an inability to discern a neurobiological condition from a recreational one.
Yet, simple questionnaires that assess symptoms are quite effective in detecting mental health and substance use disorders. Such checklists are now standard screening tools in primary care practices as well as in mental health centers as a first step in unearthing common drug induced conditions (SBIRT is an evidence based screen and early intervention for people with problems with alcohol and drugs and can be accessed here. The Patient Health Questionnaire-9 (PHQ-9) is a highly reliable and valid self-report for depression available in nine languages).