A paranoid delusion is a false belief that you are being sought after or being watched by a specific person or persons that have a negative agenda for you. This can take many form such as persecutory ideation and delusions, the roots of which reside in depression, anomalies of experience, and lowered mood.

Recent research has added insomnia to the above list of comorbidities. There does indeed seem to be a link between insomnia, paranoid delusions, and the rest of the mental/psychological conditions usually associated with it. It has been known for a while that people with persecutory delusion have a tough time initiating and maintaining proper sleep.

Why is this a potentially intriguing breakthrough?

It could mean that the effective treatment of insomnia could indirectly, yet significantly, alleviate paranoid delusion, persecutory ideation, as well as depression and anxiety.


Evidence concerning the insomnia-paranoia link

Scores of medical studies exist out there, confirming the link between insomnia and overall emotional distress. Other studies have focused on paranoia and anxious fear. Anomalies of perception and hallucination are the other components of the paranoia equation. These conditions have been linked to insomnia as well.

Furthermore, sleep problems are apparently also associated with schizophrenia. On a neurobiological level, an actual chemical link has been identified too. Over-activity of the D2 dopamine receptors has been observed in schizophrenia. This over-activity also promotes wakefulness, which is the precursor of insomnia.

Why is the insomnia-paranoia link important, above and beyond the additional treatment avenue it theoretically presents?

The prevalence of both conditions among the general population is much higher than one would believe.

While insomnia is generally well-known and discussed – probably because it does not carry the same stigma as paranoia – paranoia is much more of an unknown variable.

Some 30% of the population suffers from insomnia, with around a third of all sufferers struggling with the chronic version of the condition.

If the link between insomnia and paranoia is indeed as real and as direct as suspected, the prevalence of paranoia may approach, or even exceed that of insomnia.

Actual studies that have established the link

As mentioned, there are scores of studies that have independently verified the insomnia-paranoia link. It certainly makes sense to take a closer look at least at some of them.

A 2011 study took a look at no fewer than 2,382 participants in the 2000 British National Psychiatric Morbidity Survey. After the baseline assessment, the study followed the participants over 18 months and then re-assessed them.

The conclusions were unequivocal: a number of conditions were found to have impacted the inception of new paranoid thoughts, while supporting existing paranoid thinking. These conditions were: insomnia, depression, depressive thoughts, anxiety, and worry. Of these, insomnia stood out by a head and a shoulder. It was found to have led to a more than threefold increase in paranoid thoughts.

Worry was surprisingly paranoia-promoting as well.

Another study, the goal of which was to corroborate the findings of the above mentioned one, reduced its sample size to 300 people. The sample was taken from the general population. Added to it was another sample of 30 people, confirmed sufferers from persecutory delusion and non-affective psychosis.

They were all assessed for depression, anxiety, persecutory ideation, and insomnia. The study concluded that insomnia did lead to more anxiety and depression, and by extension: to higher levels of paranoid thinking. The “cascade” has yet again been confirmed.

The results were yet again quite unequivocal: of the subjects suffering from delusion, over 50% also suffered from severe or moderate insomnia. This kind of comorbidity is certainly indicative of a strong link between the conditions.

A study is always only as good as the methods used and its results should always be analyzed in detail. Scores of factors can impact these results, such as the fact that sometimes insomnia is nothing more than the result of daytime inactivity.

For the 330-person study, the ISI (Insomnia Severity Index) was used. The ISI is a self-report questionnaire, comprising 7 items. The purpose of the index is to provide a means for regular people to assess their difficulties in initiating and maintaining sleep and the distress caused by their inability to do so.

In addition to the ISI, the Sleep 50 Questionnaire was also employed, together with Part B of the Paranoid Thoughts Scale of Green et al. and the Depression Anxiety Stress Scales.

All the above methods were found to have entailed high internal consistency and reliability with this study.

Positive skew in the community segment of the study turned out to be an issue. This could probably be explained by the relative stigma associated with paranoia in particular, and mental/psychological conditions in general, in society.

According to the results, some 28% of the community sample had some sort of sleep-related difficulties. The most significant finding was however that some 70% of those falling into the highest category of paranoia had at least sub-threshold insomnia problems.

For those without paranoia, this rate was only 17%.

In the persecutory delusions group, only 17% were found to exhibit no insomnia-related symptoms.

Due to its methodology and sample size/nature, the study obviously entailed some shortcomings. The sample size of the clinical group was too small, the one of the community group may not have been representative.

Self-reporting is never a fully reliable way of collecting data either.

Above and beyond all else, however, none of the above studies really did much in the way of establishing the nature of the insomnia-paranoia link. They merely confirmed the existence of this link. The causality remains unknown.

Insomnia may in fact be a result of paranoid fears. A sort of vicious circle-like causality is more likely, however. It may well be that paranoid delusion feeds insomnia, which in turn promotes the former.

The bottom line

While the causal direction of the insomnia-paranoia axis remains unknown, the correlation of the two conditions (and those of anxiety and depression) is beyond doubt. Even if the mentioned vicious circle-like causality is present, the treatment of insomnia may still be a proper approach to treating paranoid delusion.