The clinical meaning of obsessive-compulsive symptoms in bipolar disorder and schizophrenia

To the Editor

The rate of co-morbid obsessive-compulsive disorder (OCD) with both bipolar and schizophrenia spectrum disorders is high. The lifetime prevalence of bipolar disorder (BD) in OCD patients is up to 21.5% and almost 50% of OCD patients have cyclothimic traits (D’Ambriosio et al., 2010). Co-morbid OCD is diagnosed in 8–32% of patients with schizophrenia (SCZ) and in up to 35% of patients with schizotypal personality disorder (de Haan et al., 2013).

On one hand, BD-OCD is associated with poorer functioning as compared to ‘pure’ BD or ‘pure’ OCD (Amerio et al., 2014). On the other hand the impact of OC symptoms (OCS) on functioning in SCZ might depend on their severity: OCS might have an improving effect while a full-blown OCD might have a worsening one (de Haan et al., 2013). In line with these findings, preliminary results of our recent study have showed a gradual transition from an improving effect (mild OCS) to a worsening one (moderate–severe OCS) on functioning in SCZ subjects.

OC symptoms are mediated by fronto-striato-thalamic circuits which have a crucial role in the regulation of daily master routines and sub-routines. Since these circuits can also be involved in the pathogenesis of BD and SCZ, OCS may have different clinical meanings in these disorders:

1. they may be an expression of a vulnerability to the development of BD and SCZ. This hypothesis implies that OCS may be the prodromic manifestations of both disorders, preceding their clinical onset for many years (D’Ambrosio et al., 2010). This means that OCS in adolescence or early adulthood can predispose to either BD or SCZ;

2. they may have a pathoplastic influence, especially in ‘soft’ bipolar and schizophrenia spectrum disorders (cyclothimia and schizotypal personality disorder); in other words OCS may constitute the superficial symptoms ‘shell’, covering the inner affective or psychotic core thorough the course of illness (and perhaps preventing the development of a full-blown disorder);

3. they might confer, at a mild level of severity, order and stability to daily life activity, thus compensating functioning decline in SCZ and possibly exerting a similar effect in BD;

4. by contrast, they may have a different relationship with BD or SCZ symptoms, since OCS appear to be independent from negative or positive symptoms in SCZ, while in BD they appear more often – and sometimes exclusively – during depressive episodes (the most frequent phase of disorder), remitting during manic/hypomanic episodes (Amerio et al., 2014).