As psychologists, the theme of diagnosis accompanies us throughout our training and professional path. It is a topic that we have dealt with countless times: in university classrooms, on textbooks, in specialization schools and, last but not least, in daily clinical practice.
Diagnosis is not only a technical tool, but also a process of reflection and understanding which pushes us to investigate the psychic dynamics of our patients deeply.
Despite the variety of approaches and strategies adopted by professionals for the evaluation, every time we return to discuss and reflect on the diagnosis we realize its complexity and its central role in Ensure targeted and personalized interventions which respects the main clinical guidelines.
However, far from being a final act, the diagnosis represents a dynamic processwhich evolves with the accumulation of information and with the progress of the therapeutic relationship.
Also, as pointed out by Nelson-Gray (2003) in his article on the concept of Treatment Utilitythe value of diagnosis and evaluation lies in their ability to contribute directly to positive therapeutic results. The therapeutic utility of the evaluation refers, in fact, to the degree in which the evaluation shows that it contributes to a beneficial treatment outcome.
In this context, the differential diagnosis takes on a crucial roleallowing to distinguish between clinical conditions that can present similar symptoms, but request different therapeutic approaches.
Differential diagnosis: what is it?
The differential diagnosis represents a fundamental step in the work of the clinical psychologist, because it allows to distinguish between disorders with apparently similar symptoms.
It is a process that goes beyond the identification of a single clinical picture and focuses onexclusion of other possible conditions. This approach is essential to ensure adequate treatment e improve the prognosis of patients, reducing the risk of interventions that could compromise their therapeutic path.
The differential diagnosis consists inAnalyze the symptoms Presented by a patient and, through careful clinical evaluation, distinguish between conditions that can overlap from the symptomatological point of view.
The need for accurate diagnosis is particularly evident when considering the numerous medical conditions that may mimic the symptoms of the psychological disorders described in the DSM-5-TR (McGuinness et al, 2012). The ability to recognize these cases is crucial, especially in situations in which patients follow pharmacological therapies, since inappropriate psychotropic drugs they can mask or aggravate physical problems below, with potentially serious consequences.
This diagnostic ability is based on biopsicosocial model (Engel, 1977; Muse, 2017), which integrates biological, psychological and social factors for a more complete understanding of the patient.
The differential diagnosis thus allows you to customize the treatment and reduce the risk of ineffective or harmful interventions. It also allows us to have a more centered focus on the patient’s difficulties and resources.
While the clinical diagnosis aims to identify a specific psychopathological condition, the differential diagnosis focuses on the comparison between different possible diagnoses to exclude the less probable ones.
This process is particularly important in cases of comoribility or of Symptoms that can be shared by multiple ailments. For example, some manifestations of neurosviluppo disorders, such as autistic spectrum disorder and ADHD, share similar diagnostic criteria, but require different therapeutic approaches (McCary et al., 2012). The lack of distinction between these disorders can lead to inadequate interventions and a worsening of the patient’s quality of life.
A further example concerns the dissociative disorders And some neurological conditions, such as the epilepsy of the temporal lobe, which present superimposable symptoms. Sivec and Lynn (1995) underline the importance of a structured diagnostic approach, supported by validated tools, to distinguish between psychological disorders and medical conditions.
Differential diagnosis as a structured path
Summarizing a complex and articulated process such as differential diagnosis is not simple, but we can outline some fundamental phases who guide the professional in the clinical evaluation:
- anamnestic and clinical data collection
- evaluation of symptoms and diagnostic criteria
- evaluation of possible alternative conditions
- exclusion of other conditions that could explain the symptoms
The differential diagnosis begins, therefore, with one accurate collection of patient data.
This crucial passage includes the exploration of the medical and psychological history Of the patient, any previous medical conditions, current symptoms and contextual factors, such as the family and social environment.
These data provide the base to understand the patient’s overall picture. As pointed out by Fintein (1997) in the study on the differential diagnosis of dementia, the detailed collection of this information allows, for example, to distinguish between conditions such as dementia, delirium and other neurological pathologies.
After collecting the data, the next step consists of compare the symptoms shown with the diagnostic criteria defined in the main manuals, such as the DSM-5 or the ICD-11 or the ICF. For example, Hollis and Remschmidt (2001) show that, in the case of schizophrenia, it is necessary to consider how the symptoms can vary depending on the patient’s development phase. This approach reduces the risk of underestimating or confusing symptoms based on age or context.
Finally, the differential diagnosis requires the exclusion of other conditions that could explain the symptoms. This process is based on acomparative analysis which includes the evaluation of medical, neurological and psychological disorders, ensuring that the treatment is targeted and appropriate. For example, depressive symptoms can derive from both a greater depressive disorder and from an underlying medical condition, such as hypothyroidism. Correctly identifying the primary cause is essential for the success of the treatment.
The tools for making the differential diagnosis
Each phase of the differential diagnosis process requires the professional, expert or not, to make use of fundamental tools that allow for a thorough and accurate evaluation.
The clinical interview remains one fundamental tool To explore the patient’s history, the subjective experiences and the symptoms reported. Through the interview, the professional can collect useful information to build a complete and in -depth diagnostic picture. As highlighted by Fintein (1997), structured or semi-structured interviews are particularly useful in the evaluation of complex conditions such as dementia, in which cognitive, emotional and social symptoms intertwine.
The Psychometric and neuropsychological toolson the other hand, allow to evaluate cognitive, emotional and behavioral aspects in a standardized way. In neuro -evolutionary disorders and cognitive deficits, in fact, neuropsychological tests provide precious information to distinguish between deficits linked to pathologies such as dementia and those associated with conditions such as depression. These tools support the clinician in differential diagnosis minimizing the margin of diagnostic error.
THE’direct observation of behavior of the patient is another key tool. This approach allows you to identify non -verbalized signs or inconsistencies between what is reported by the patient and what is observed. In the case of schizophrenia or behavioral disorders, behavioral observation helps to identify signs of disorganization, negative symptoms and specific deficits (Hollis and Remschmidt, 2001).
Differential diagnosis: some examples
As we have observed, carrying out an accurate differential diagnosis is essential to distinguish between disorders with similar symptoms. It becomes important to note that some of these overlaps are more frequent than others. For example:
ADHD and Autism (ASD) present superimposable symptomsas difficulties in attention and problems in the regulation of behavior. However, while the ADHD is characterized by hyperactivity and impulsiveness, the ASD includes social communication deficits and repetitive behaviors. Standardized tests to evaluate specific characteristics of both disorders are fundamental to avoid diagnostic confusion (Matson et al., 2006).
Social isolation and rigid thoughts in autism can be confused with i Negative symptoms of psychosis. However, as highlighted by Friguux et al. (2021), Psychosis stands out for delusions and hallucinations, while in autism, difficulties related to perception and social interpretation are observed.
Although they share symptoms such as deficit in communication and abstract thought, schizophrenia typically presents a late debut compared to autism and includes psychotic symptoms such as delusions and hallucinations. A careful diagnosis requires a thorough historical analysis and the use of diagnostic tools such as the DSM-5 (De Lima et al., 2023).
Unipolar depression and bipolar disorder share depressive episodes, but the latter is also characterized by Maniacal or hypomaniacal episodes. A detailed evaluation of the patient’s emotional anamnesis is essential for a correct diagnosis and to prevent ineffective or harmful treatments.
Specific learning disorders (DSA) and ADHD can coexist or be confused, since they both influence school performance. However, DSA concerns specific difficulties in academic skills (reading, writing, calculation), while the ADHD mainly affects self -regulation and attention. Neuropsychological and psychometric tests can be useful for distinguishing between the two.
Continuous training can promote more human diagnosis
Differential diagnosis is a complex process that requires not only advanced skills and the use of specific tools, but also a human approach and contextualized. The symptoms reported in diagnostic manuals, such as the DSM-5, cannot be considered mere aseptic elements or rigid criteria to be satisfied.
The differential diagnosis pushes the clinician to imagine the way the symptoms impact in the context of the real life of the patient, understanding the personal meaning and implications for his daily experience.
For those who want to deepen this theme, the manual is recommended DSM 5. Differential diagnosis (First, 2015).
Investing in continuous training is essential for mental health professionals. A constant update allows you to maintain a Evidence -based approach and to integrate theoretical knowledge with clinical sensitivity. Understand symptoms not only as objective signs, but also as expressions of complex experiencesenriches the diagnostic process and improves the quality of the intervention.
This commitment to excellence increases the skills of the clinician and promotes a concrete benefit for patientsguaranteeing a personalized, human and scientifically valid taking charge.
