Personality disorders and schizophrenia

Chapter 5 Personality disorders and schizophrenia

KEY POINTS

• Schizophrenia often manifests early in a person’s developmental trajectory and can impact personality development.

• There are neurobiological factors that link schizotypal personality disorder (SPD) and schizophrenia might be considered a ‘forme fruste’ of schizophrenia.

• People with borderline personality disorder can manifest positive psychotic phenomena that cross-sectionally mimic those of schizophrenia.

• Paranoid personality disorder and psychopathic personality disorder can overlap with schizophrenia, but most people with schizophrenia are not psychopathic.

In Chapter 3, we described the underpinnings of the proposed hierarchical model of mental illness and the emergence of transdiagnostic psychiatry. These constructs are particularly relevant to the consideration of personality disorders as a comorbidity. On one level, the co-existence of personality disorders is antithetical to this hierarchical model, since under this model schizophrenia is considered to be ‘at the top of the food chain’ and subsumes all other possible diagnoses below (Castle and Buckley 2015; Fusar-Poli 2019). That said, schizophrenia is a condition of pervasive impairments, including that of personality development. This is, of course, particularly so when the onset of psychosis is in youth—early adolescence—which occurs in approximately 25% of individuals (McCutcheon et al. 2020). Moreover, negative symptoms such as avolition, amotivation, anhedonia, and asociality are themselves barriers to the development of the interpersonal relationships that shape personality development (Simonsen and Newton-Howes 2018). Accordingly, consideration of the relationship of personality disorders to the comorbidities of schizophrenia is more selective and circumscribed, as detailed in Boxes 5.1 and 5.2.

Box 5.1 Personality disorders more associated with schizophrenia

Box 5.2 Personality disorders not usually associated with schizophrenia

• Histrionic

• Narcissistic

• Obsessive compulsive

• Avoidant

• Dependent

Borderline personality disorder and schizophrenia

Borderline personality disorder (BPD) is a pervasive pattern of chaotic interpersonal relationships, anger and agitation, intense feelings of emptiness, instability of mood, and often agitated and self-destructive behaviours. It is important to appreciate that in earlier conceptualizations of mental disorders, BPD was clustered with schizotypal personality disorder (SPD). It had antecedents with earlier constructs characterized by a lack of positive symptoms: ‘latent schizophrenia’ or ‘borderline schizophrenia’ or ‘pseudo-neurotic schizophrenia’. Josef Parnas, a Danish psychiatrist, is a proponent of this historical antecedent and he has articulated a fundamental relationship between BPD and schizophrenia—one that is encompassed in the model of schizophrenia spectrum disorder (Parnas 2015).

For most patients with BPD, mood disorders, depression, anxiety disorders and substance abuse are the most common and the major comorbidities, and schizophrenia, an especially chronic relapsing illness, is relatively rarely associated with BPD. Having said this, people with BPD are vulnerable to psychotic phenomena that cross-sectionally are similar to the positive symptoms of schizophrenia. For example, studies of auditory hallucinations in individuals with BPD suggest a similar pattern to auditory hallucinations in schizophrenia. Detection of hallucinations is often complicated by reluctance by the patient to describe such ‘ego-dystonic’ experiences. All that said, individuals with BPD are prone to brief psychotic episodes (Simonsen and Newton-Howes 2018). These are characterized by short-lived hallucinations, paranoid thinking (even to the point of paranoid delusions), and marked anxiety-agitation. These ‘micro-psychoses’ can occur in individuals with BPD at times of heightened emotional instability (where, under stress, the person in layman’s terms ‘loses it’). However, brief psychotic episodes that occur in PBD are further complicated as they can occur in the context of use of licit or illicit drugs. In either instance, symptoms subside as the individual becomes less anxious and as the mental state ‘reconstitutes’. Antipsychotic medications are usually not indicated in such instances: benzodiazepines are often the more effective option. However, antipsychotics have been studied in BPD to manage chronic instability of mood and anxiety-agitation. There has been some research of a low dose of olanzapine that may demonstrate some small benefit in BPD patients (Camchong et al. 2018). Adverse effects of second-generation antipsychotics, especially weight gain, undermine medication compliance and efficiency particularly in patients with BPD (Koch et al. 2016).

There is no evidence of a ‘kindling effect’ or successive ‘micro-psychoses’ that might ultimately devolve to a chronic schizophrenic condition. Similarly, the combination of BPD and cannabis use is no more likely to result in psychosis than is cannabis use alone, though of course there is a heightened rate of cannabis use disorder among BPD patients (Gillespie et al. 2018). A recent study demonstrates similar stress intolerance between people with schizophrenia and people with BPD (Bonfils et al. 2020).

Paranoid personality disorder and schizophrenia

As the name implies, paranoid personality disorder (PPD) is a condition associated with intense and selective mistrust of others and/or situations, paranoid thinking and misinterpretation of events, and associated social isolation (Lee 2017). There can be social and/or occupational impairments, although these are less pronounced than in schizophrenia or other major psychiatric conditions. People with PPD can often be litigious and they can pursue ‘redress’ for perceived or objectively slight grievances they hold with unshakable conviction. Compared to other psychotic and/or mood disorders, or even compared to other personality disorders, PPD is quite rare. It has high comorbidity with mood disorders, specifically depression, and with anxiety disorders. There is not any notable comorbidity of PPD with schizophrenia and it has not been a feature in recent large epidemiological, descriptive, or genetic studies in schizophrenia. That said, in the 1960s, Sir Martin Roth proposed a ‘paranoid spectrum’, linking paranoia, PPD and paranoid schizophrenia—especially a late-onset form of paranoid schizophrenia that he termed ‘paraphrenia’. Current conceptualizations in geriatric psychiatry recognize the distinction of late-onset schizophrenia, though no link is drawn anymore to PPD and in general this relationship of PPD to schizophrenia is more tenuous than heretofore considered (Lee 2018).

Medication treatment for PPD is limited and adherence to medications is distinctly low due to lack of insight into this condition (Koch et al. 2016).