Drawing the Line Between Obsessive-Compulsive Disorder and Schizophrenia

The schizo-obsessive spectrum has been a central focus of interest and research within the scientific community in mental health. The increased comorbidity of schizophrenia and obsessive-compulsive symptoms (OCS) or obsessive-compulsive disorder (OCD) appears to be considerably higher than previously expected, with more recent studies suggesting growing prevalence rates. Despite this phenomenon, OCS are not considered primary manifestations of schizophrenia and are therefore not usually explored in these patients. The concept of schizo-obsessiveness mostly emerged in the 1990s, progressing into OCD-schizophrenia spectrum disorders as a dual diagnosis of OCD and schizophrenia. The manifestations of the schizo-obsessive spectrum are diverse, and its diagnoses may be divided overall into four main categories: schizophrenia with OCS; schizotypal personality disorder (SPD) with OCD; OCD with poor insight; schizo-obsessive disorder (SOD). In some cases, distinguishing an intrusive thought from delirium in OCD with poor insight might be challenging. Poor or absent insight can be present in many diagnoses of OCD. Those patients within the schizo-obsessive spectrum present a worse insight than those with OCD without schizophrenia. The comorbidity has important clinical implications, considering its association with an earlier onset of the disorder, more severe positive and negative psychotic symptoms, a greater cognitive deficit, more severe depressive symptoms, more suicide attempts, a reduced social network, increased psychosocial dysfunction, and consequently a worse quality of life and greater psychological suffering. The presence of OCS or OCD in schizophrenia may lead to more severe psychopathology and a worse prognosis. More precise diagnoses allow for a more targeted intervention by offering an optimized psychotherapeutic and psychopharmacological approach. We hereby present four clinical cases that represent each of the four designated categories of the schizo-obsessive spectrum. This case-series report aims to enhance clinical insight regarding the diversity of the schizo-obsessive spectrum and to illustrate the difficult and sometimes misleading process of differentiating OCD from schizophrenia and establishing a diagnosis due to the potential overlap of phenomenology, as well as the course and assessment of symptoms manifested within the spectrum.