How Does Obsessive-Compulsive Disorder Affect Thinking in People with Psychosis?

What you need to know

• This study looked at whether having obsessive-compulsive symptoms affects thinking and cognition in people with psychotic disorders.
• Overall, the researchers did not find clear evidence that obsessive-compulsive symptoms are linked to better or worse cognitive functioning in people with psychosis.
• There was a lot of variation between individual studies, suggesting this is a complex issue influenced by many factors.
• Older age was associated with relatively worse cognitive performance in those with obsessive-compulsive symptoms.

Background

People with psychotic disorders like schizophrenia often experience cognitive difficulties that can impact their daily functioning. Some people with psychosis also have obsessive-compulsive symptoms (OCS) or obsessive-compulsive disorder (OCD). Researchers wanted to know if having OCS along with psychosis affects a person’s cognitive abilities.

Obsessive-compulsive symptoms involve recurring, intrusive thoughts (obsessions) and repetitive behaviors or mental acts (compulsions). Examples include excessive hand washing due to fears of contamination or repeatedly checking that doors are locked.

What did the researchers do?

The researchers conducted a meta-analysis, which means they combined and analyzed data from multiple previous studies on this topic. They looked at 30 studies that included a total of 2,738 patients with psychotic disorders. These studies compared cognitive test results between patients who had obsessive-compulsive symptoms and those who did not.

The analysis examined 17 different areas of cognition, including:

• Attention and processing speed
• Memory
• Executive functions (like planning and decision-making)
• Social cognition (understanding others’ emotions and intentions)

Key findings

Overall, the meta-analysis did not find significant differences in cognitive functioning between psychosis patients with and without obsessive-compulsive symptoms. This was true across most of the cognitive domains they examined.

However, there was one exception: When looking specifically at tests of processing speed that weren’t purely based on reaction time, patients with OCS performed slightly worse than those without OCS.

Importantly, the researchers found a lot of variation between individual studies. Some studies showed better cognitive performance in patients with OCS, while others showed worse performance. This suggests the relationship between OCS and cognition in psychosis is complex.

Factors that may influence cognitive performance

The researchers looked at several factors that might help explain the variation between studies:

• Age: In studies with older participants, patients with OCS tended to perform relatively worse on tests of processing speed, working memory, cognitive inhibition, and cognitive flexibility compared to those without OCS.

• OCD diagnosis: Interestingly, in studies where patients had a full OCD diagnosis (not just some OCS), they performed better on tests of cognitive inhibition compared to those with milder OCS. This was unexpected and needs further investigation.

• Symptom severity: The researchers did not find clear evidence that the severity of psychotic symptoms or obsessive-compulsive symptoms was related to cognitive performance.

Conclusions

• Having obsessive-compulsive symptoms does not appear to consistently improve or worsen cognitive functioning in people with psychotic disorders.
• The relationship between OCS and cognition in psychosis is complex and likely influenced by many factors.
• More research is needed to understand why some patients with OCS show better cognitive performance while others show worse performance.

Why this matters

Understanding how obsessive-compulsive symptoms impact cognition in people with psychosis is important for several reasons:

1. It can help clinicians better understand and treat patients who experience both conditions.
2. It may provide insights into the underlying brain mechanisms involved in psychosis and obsessive-compulsive disorder.
3. It could potentially inform treatment approaches aimed at improving cognitive functioning in these patients.

The findings highlight the need for individualized assessment and treatment approaches for people with psychosis and obsessive-compulsive symptoms, as their cognitive profile may vary based on factors like age and symptom characteristics.

Limitations and future directions

The researchers note several limitations of their analysis:

• Many studies used different cognitive tests, making direct comparisons challenging.
• Important information was often missing from individual studies, such as medication use or duration of illness.
• Most studies excluded patients with substance use problems, which are common in psychosis and may impact cognition.

Future research in this area should:

1. Use standardized cognitive tests across studies to improve comparability.
2. Consider how factors like medication, illness duration, and substance use may influence cognitive performance.
3. Take a more nuanced approach, looking at specific types of obsessive-compulsive symptoms rather than grouping all OCS together.
4. Conduct more long-term studies to see how the relationship between OCS and cognition in psychosis may change over time.

By addressing these points, researchers can gain a clearer understanding of how obsessive-compulsive symptoms impact thinking and functioning in people with psychotic disorders, ultimately leading to better treatment approaches.