For example, someone compulsively checking the front door may argue that the time and stress associated with one check is less than the time and stress associated with being robbed, and checking is consequently the better option. This reasoning often occurs in a cyclical manner, and can continue for as long as the affected person needs it to in order to feel safe.In cognitive behavioral therapy (CBT), OCD patients are asked to overcome intrusive thoughts by not indulging in any compulsions. They are taught that rituals keep OCD strong, while not performing them causes OCD to become weaker. This position is supported by the pattern of memory distrust; the more often compulsions are repeated, the more weakened memory trust becomes, and this cycle continues as memory distrust increases compulsion frequency. For body-focused repetitive behaviors (BFRB) such as trichotillomania (hair pulling), skin picking, and onychophagia (nail biting), behavioral interventions such as habit reversal training and decoupling are recommended for the treatment of compulsive behaviors.OCD sometimes manifests without overt compulsions, which may be termed "primarily obsessional OCD." OCD without overt compulsions could, by one estimate, characterize as many as 50–60% of OCD cases. Insight and overvalued ideation
The DSM-5 identifies a continuum for the level of insight in OCD, ranging from good insight (the least severe) to no insight (the most severe).
Some people with OCD have areas of unusually high activity in their brain, or low levels of the chemical serotonin, which is a neurotransmitter that some nerve cells use to communicate with each other, and is thought to be involved in regulating many functions, influencing emotions, mood, memory, and sleep. Autoimmune
A controversial hypothesis is that some cases of rapid onset of OCD in children and adolescents may be caused by a syndrome connected to Group A streptococcal infections (GABHS), known as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS). OCD and tic disorders are hypothesized to arise in a subset of children as a result of a post-streptococcal autoimmune process. The PANDAS hypothesis is unconfirmed and unsupported by data, and two new categories have been proposed: PANS (pediatric acute-onset neuropsychiatric syndrome) and CANS (childhood acute neuropsychiatric syndrome). The CANS and PANS hypotheses include different possible mechanisms underlying acute-onset neuropsychiatric conditions, but do not exclude GABHS infections as a cause in a subset of individuals. PANDAS, PANS, and CANS are the focus of clinical and laboratory research, but remain unproven. Whether PANDAS is a distinct entity differing from other cases of tic disorders or OCD is debated.A review of studies examining anti-basal ganglia antibodies in OCD found an increased risk of having anti-basal ganglia antibodies in those with OCD versus the general population. Environment
OCD may be more common in people who have been bullied, abused, or neglected, and it sometimes starts after a significant life event, such as childbirth or bereavement.