Difference Between Provisional and Differential Diagnoses

A doctor is going to be very careful when diagnosing depression or any other mental disorder. In some cases, you may have either a provisional or differential diagnosis until more information can be gathered. The key is to be patient and honest because this will help a doctor create the proper treatment plan for you.

This article covers the definitions of provisional diagnosis and differential diagnosis. It also reviews a particular approach to the differential diagnostic process a doctor or healthcare professional might use for making a diagnosis.

What Is a Provisional Diagnosis?

A provisional diagnosis means that a doctor is not 100% sure of a diagnosis because more information is needed. With a provisional diagnosis, a doctor makes an educated guess about the diagnosis you most likely have.

Under the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a provisional diagnosis is indicated by placing the specifier "provisional" in parentheses next to the name of the diagnosis. For example, it might say something like "309.81 Post-traumatic Stress Disorder (provisional)."

Once more information is gathered and a final diagnosis is made, this specifier is removed.

What Is a Differential Diagnosis?

A differential diagnosis means that there is more than one possibility for your diagnosis. A doctor must differentiate between multiple diagnoses to determine the correct one and make an appropriate treatment plan.

For instance, there are currently no lab tests to identify depression. Instead, the diagnosis is based on your history and your symptoms. It is also necessary to rule out other potential causes because many medical and mental health conditions have similar or overlapping symptoms as each other.

According to Dr. Michael B. First, Professor of Clinical Psychiatry at Columbia University and author of the DSM-5 Handbook of Differential Diagnosis, making a good differential diagnosis of depression involves the six steps listed below.

Step 1: Rule Out Malingering and Factitious Disorder

According to Dr. First, a doctor's initial step should be an attempt to determine whether patients are not fully honest about their symptoms. In general, there are two possible reasons for this: malingering disorder or factitious disorder.

Step 2: Rule Out Drug-Related Causes

Certain drugs—both legal and illegal—can cause the same symptoms as depression when misused or even when used as prescribed. These can include the drugs listed below.

Prescription and Over-the-Counter Drugs

For instance, the following are medications that can cause the symptoms of depression:

• Anticholinergic drugs: Such as Bentyl (dicycloverine)
• Anticonvulsants: Tegretol (carbamazepine), Topamax (topiramate), and Neurontin (gabapentin)
• Benzodiazepines: Xanax (alprazolam), Restoril (temazepam), and Valium (diazepam)
• Beta-blockers: Metoprolol and Inderal (propranolol)
• Corticosteroids: Cortisone, prednisone, methylprednisolone, and triamcinolone
• Drugs that affect hormones: Birth control pills and estrogen replacement therapy
• Opioids: Oxycodone, morphine, and fentanyl
• Statins and other cholesterol-lowering drugs: Such as Lipitor (atorvastatin)

Illicit or Recreational Drugs

Below are illicit drugs that can cause the symptoms of depression:

• Alcohol
• Heroin
• Inhalants (solvents, aerosol sprays, gases, nitrates)
• Phencyclidine (PCP, also known as angel dust)
• Psychedelics (LSD, magic mushrooms, ketamine)

Clinicians can gain clues about illicit drug use, Dr. First says, by interviewing the patient. Sometimes, the family is interviewed as well. They can also look for signs of intoxication and perform blood or urine tests to screen for the presence of both licit and illicit drugs.

Step 3: Rule Out Other Medical Conditions

There are various general medical conditions that can present with psychiatric symptoms. For this reason, it is very important to rule out any underlying conditions when making a diagnosis because they often require unique treatment.

To rule conditions out, clinicians will ask about previously diagnosed conditions. They are particularly interested in those that may have begun around the same time as depression. Lab tests may be ordered to screen for conditions commonly associated with the symptoms of depression.

Some general medical conditions commonly mistaken for depression include:

• Autoimmune disorders (such as rheumatoid arthritis and lupus)
• Chronic fatigue syndrome
• Diabetes
• Fibromyalgia
• Hypothyroidism
• Lyme disease
• Sleep disorders

Step 4: Determine the Primary Disorder

Once other potential causes have been eliminated, it is necessary to distinguish which specific psychiatric disorder the patient has.

Clinicians must differentiate major depressive disorder from related mood disorders and other disorders which often coexist with depression. This is done by following the criteria established in the DSM-5.

Step 5: Differentiate It From Other Categories

There are times when a person's symptoms are significant but below the threshold to make a diagnosis or the symptoms are clearly related to stress or a trauma.

Dr. First suggests that the clinician consider a diagnosis of adjustment disorder. This is a condition in which the emotional or behavioral symptoms occur within a few months of an identifiable stressor and are severe enough to cause marked distress or significant impairment in functioning.

If symptoms are present and significant but don't meet full criteria for an established diagnosis, and they are not related to a clear stressor, the categories of "other specified" or "unspecified" might be applied.

Step 6: Establish Boundary

Finally, clinicians need to make a judgment call. They need to determine whether the patient is experiencing significant enough impairment or distress in everyday life, and that this impairment has lasted long enough in order for it to qualify as a mental disorder.

A Word From Verywell

Properly diagnosing depression or any other mental health condition is the first step in treating the whole person. With a proper diagnosis, you can work with a doctor or mental health professional to come up with an effective treatment plan, which may involve a combination of medications, psychotherapy, and lifestyle changes to get back in balance and feel like yourself again.