Difference Between Provisional and Differential Diagnoses

Your 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.

What does that mean and what's the standard procedure for a diagnosis? These are the questions we'll answer so you can fully understand the process. The key is to be patient and honest because this will help your doctor create the proper treatment plan for you.

What Is a Provisional Diagnosis?

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

Under the newest edition of 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 Posttraumatic 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. Your doctor must differentiate between these to determine the actual diagnosis and appropriate treatment plan.

Unfortunately, there are currently no lab tests to identify depression. Instead, the diagnosis is based on your medical history and your symptoms. It is also necessary to rule out other potential causes because there are several medical conditions that may appear to be depression on the surface with shared symptoms.

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 six steps.

Step 1: Rule Out Malingering and Factitious Disorder

According to First, a doctor's initial step should be an attempt to determine whether patients are faking their symptoms. In general, there are two possible reasons for this: malingering and 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 used as prescribed. This can include the following:

Prescription and Over-the-Counter Drugs

Below are medications that can cause the symptoms of depression:

• Anticholinergic drugs: Bentyl
• 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, estrogen replacement therapy
• Opioids
• Statins and other cholesterol-lowering drugs

Illicit or Recreational Drugs

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

• Alcohol
• Hallucinogens: LSD, magic mushrooms (psilocybin), ketamine
• Heroin
• Inhalants (solvents, aerosol sprays, gases, nitrates)
• Phencyclidine: PCP (Angel Dust)

It is fairly easy to know if someone is taking prescriptions, it may be necessary for a doctor to do a little investigation when it comes to drugs of abuse.

Clinicians can gain clues about illicit drug use, 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 General Medical Conditions

There are various conditions in which depression is a symptom. It is very important to rule these out because it may require treatment beyond psychotherapy or an antidepressant medication to remove or mitigate the underlying causes of depression. 

To do this, 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 conditions commonly mistaken for depression include:

• Attention-deficit/hyperactivity disorder (ADHD)
• Autoimmune disorders (such as rheumatoid arthritis and lupus)
• Bipolar disorder
• 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 another diagnosis.

First suggests that the clinician consider a diagnosis of adjustment disorder. This is a condition in which the symptoms are maladaptive—not typical—in response to the psychological stressor. This means that the symptoms keep you from coping with the disorder. Some common examples of maladaptive behavior include avoidance, passive communication, anger, and substance use.

If that category is not appropriate, they could then consider placing the diagnosis into either "other" or "unspecified" categories.

Step 6: Establish Boundary

Finally, clinicians need to make a judgment call. They need to determine whether the patient is experiencing significant impairment or distress in everyday life that would qualify as a mental disorder.

In addition, clinicians must distinguish major depressive disorder from grief. While grief may cause significant impairment and distress, it may not necessarily 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 your 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.