Thought loops are the experience of becoming trapped within a chain of thoughts, actions and emotions which repeats itself over and over again in a cyclic loop. These loops usually range from anywhere between 5 seconds and 2 minutes in length. However, some users have reported them to be up to a few hours in length. It can be extremely disorientating to undergo this effect and it often triggers states of progressive anxiety within people who may be unfamiliar with the experience. The most effective way to end a cycle of thought loops is to simply sit down and try to let go.
This state of mind is most likely to occur during states of memory suppression in which there is a partial or complete failure of the person's short-term memory. This may suggest that thought loops are the result of cognitive processes becoming unable to sustain themselves for appropriate lengths of time due to a lapse in short-term memory, resulting in the thought process attempting to restart from the beginning only to fall short once again in a perpetual cycle.
When this effect occurs in conjunction with high level internal hallucinations, it often results in the hallucinatory scenarios repeating themselves in the same way the person's thoughts are. These looped hallucinations can remain exactly the same with each repetition, but will often change in their overall details while maintaining specific themes and elements throughout each iteration.
Thought loops are most commonly induced under the influence of heavy dosages of hallucinogenic compounds,  such as psychedelics and dissociatives. However, they can also occur to a lesser extent under the influence of extremely heavy dosages of stimulants and benzodiazepines.
- Bersani, F. S., Corazza, O., Albano, G., Valeriani, G., Santacroce, R., Bolzan Mariotti Posocco, F., ... & Schifano, F. (2014). 25C-NBOMe: preliminary data on pharmacology, psychoactive effects, and toxicity of a new potent and dangerous hallucinogenic drug. BioMed Research International, 2014. | https://doi.org/10.1155%2F2014%2F734749