Differential Diagnosis -Definition, Steps and Examples

Have you heard about differential diagnosis? It’s a process where a doctor differentiates between two or more conditions that could be behind a person’s symptoms. After all, there are many disorders that have similar symptoms. Read on to learn more.
Differential Diagnosis -Definition, Steps and Examples

Last update: 15 January, 2022

It’s disturbing to think that you’re different from everyone else. That your thoughts, emotions, and behaviors differ significantly from those around you. It can make you feel flawed, isolated, and misunderstood. However, in many cases, receiving a diagnosis can help alleviate these feelings of discomfort. On the other hand, if you receive an incorrect diagnosis, the harm may outweigh the benefits. Hence, the importance of differential diagnosis.

Identifying a mental condition isn’t always easy. Furthermore, sufferers are generally slow to seek help. In addition, it’s not unusual for an individual to receive different diagnoses over time. Also, results can take time to arrive, and sometimes, the interventions carried out aren’t the most appropriate.

The labels you’re given may seem irrelevant. However, they’re actually of great importance.

An image of a depressed woman.

Do labels define you?

There are mixed and controversial opinions regarding labels. Some people feel that terms like ‘anxiety’, ‘depression’, ‘attention deficit’, and ‘personality disorder’ are limiting and condemning. They suggest that, in many cases, having received a diagnosis, the individual is then reduced to this label in the face of others and even of themselves. This can be harmful to them and even encourage the advancement of a disorder.

On the other hand, the value of receiving a response that explains the symptoms being experienced is undeniable. Indeed, obtaining an accurate diagnosis is beneficial on several levels:

  • It allows the patient to make sense of the experience, to understand why they’re feeling, thinking, or acting in a certain way, and to take responsibility for themselves.
  • It helps them identify the possible origin of their condition. Furthermore, why it’s arisen in the context of their own biological and environmental variables.
  • It offers the patient the opportunity to connect with other people with the same experiences. This reduces feelings of isolation and misunderstanding.
  • It’s the first fundamental step toward the commencement of adequate treatment. Indeed, the diagnosis is received and the professional is able to begin to work with the disorder in order to improve the quality of life of the sufferer.

The importance of differential diagnosis

Differential diagnosis can be defined as the process that’s carried out to differentiate one specific illness from other similar ones. In other words, during the psychological evaluation, the professional is able to take other similar or related disorders into account in order to identify which one the patient is suffering from.

This seemingly simple task requires the following:

  • In-depth knowledge on the part of the professional of the different diagnostic categories and their criteria.
  • An individualized evaluation, in which the background of the patient, their life history, and particular circumstances and symptoms are analyzed.
  • The active participation of the patient in offering all the relevant information. This is because, sometimes, a misdiagnosis can be made because the patient hasn’t established a strong enough relationship of trust with the therapist in order to provide certain key information. For example, many people are reluctant to admit that they hear voices.

Differential diagnosis and comorbidity

One of the main difficulties arises from the fact that it’s common for several psychological disorders to overlap, occur at the same time, or depend on each other. In these cases, the professional must identify all those present and clarify the relationship between them.

For example, if a patient asks for help due to the high anxiety that they feel when socializing, the professional may think they have social phobia. However, if they also stutter, this could actually be the cause of their social anxiety.

A differential diagnosis looks at the possible disorders that could be causing these symptoms. It generally involves several tests. These can usually rule out certain conditions while also determining if more tests are needed.

On the other hand, a patient suffering from a dysmorphic disorder ( an obsession with a real or imaginary physical defect) may also suffer from ED (eating disorder). Therefore, both conditions should be addressed.

Woman and therapist.

Follow-up is essential for a successful differential diagnosis

Given all these complexities, it’s important that the diagnosis remains open to revision and modification even once it’s been established. In fact, it’s possible that previously unknown data will be discovered over the course of these sessions and treatment will need to be altered. Or, if the intervention isn’t proving effective, it could be that there’s some element that hasn’t yet been considered and that points to a different diagnosis.

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  • Wittchen, H.-U. (1996). Critical issues in the evaluation of comorbidity of psychiatric disorders. The British Journal of Psychiatry, 168(Suppl 30), 9–16.
  • Behar, R., Arancibia, M., Heitzer, C., & Meza, N. (2016). Trastorno dismórfico corporal: aspectos clínicos, dimensiones nosológicas y controversias con la anorexia nerviosa. Revista médica de Chile144(5), 626-633.