According to Millon, personality is a “complex pattern of psychological factors, which are mostly unconscious and express themselves automatically in almost every functional dimension of the subject”. It has been described how personality traits can modify the expression of other mental diseases, leading to confusion in diagnosis and treatment of the patient.

Systematic review of the literature in English (PubMed) and clinical history of the patient. Keywords: “recurrent depression disorder”; “schizoid personality”.

To highlight the importance of making an accurate and detailed diagnostic formulation, in patients with both mental and personality disorders.

Sixty-seven-year-old woman, with many psychiatric hospitalizations, secondary to a recurrent depression disorder with psychotic symptoms and schizoid personality disorder. Both psychiatric monitoring and pharmacological treatment have been erratic. Initially, depressive episodes were considered as symptoms of her personality disorder. However, over the years, it was possible to make a more accurate diagnosis and a better treatment adjustment. In this case, lack of adherence is probably due to multiple factors, but no awareness of illness and personality disorder itself are the most important ones. This fact makes the patient less concerned about her personal care, leading to irregular treatment.

People with schizoid, schizotypal or paranoid personality traits usually have a worse outcome, and they interfere with the functionality of the patient. This explains the importance of making an accurate and detailed diagnostic formulation, in order to benefit the course of the underlying mental disorders.

The authors have not supplied their declaration of competing interest.