OCD explanations Flashcards
genetic explanation
Lewis (1936) found OCD runs in families—37% had a parent and 22% a sibling with OCD.
Twin study by Carey & Gottesman (1981) showed 87% concordance in MZ twins vs 47% in DZ, suggesting strong genetic influence as MZ twins share more genes, not just environment.
candidate genes
in 2013, 230 genes had been linked to OCD (taylor 2013)
by now this figure probs higher
shows that OCD is another example of a polygenic disorder
research also suggests that diff genes are linked to the diff types of OCD eg contamination and checking
5-HTT and serotonin
OCD has been linked to genes affecting serotonin (e.g., receptor, transporter, and MAO-A). A mutation in the 5-HTT gene (Ozaki et al., 2003) may increase vulnerability, but it’s also linked to other disorders, making OCD-specific causes unclear
DRD4, COMT, and dopamine
DRD4 gene (dopamine receptor) may be linked to OCD—allele 2 is less common in OCD patients, suggesting a protective effect (Millet et al., 2003). Low-activity COMT allele is more common in OCD, possibly causing excess dopamine and increasing vulnerability.
SLITRK4 and BDNF
SLITRK genes help form new synapses; SLITRK5 has been linked to OCD. It may affect levels of BDNF, a protein that maintains healthy neural networks—low BDNF may lead to abnormal thoughts and behaviour.
genetic eval determinism vs free will
A strength of the genetic explanation is research support—Shmelkov et al. (2010) found that mice with the SLITRK5 gene silenced showed OCD-like behaviours (e.g., compulsive grooming, hoarding), suggesting genetic links. However, mice lack human consciousness and social pressures, so findings may not fully generalise to human behaviour.
genetic eval nature vs nurture
A weakness of the genetic explanation is that it overlooks cultural differences, suggesting nurture also plays a role. Fontenelle et al. (2004) found 70% of OCD cases in Brazil involved violent obsessions vs. 16% in Singapore, possibly due to Brazil’s rising crime. This shows OCD symptoms are shaped by environment, though some traits may have evolved to increase survival by encouraging caution
biochemical explanation
serotonin
OT
serotonin, dopamine, and BDNF
Imbalance of serotonin (linked to 5-HTT gene) may increase OCD risk due to issues with serotonin transport, receptors, or breakdown by enzymes like MAO-A. Abnormal D4 dopamine receptors and low BDNF levels may also raise vulnerability.
role of oxytocin
Repetitive behaviour in OCD overlaps with ASD; Hollander et al. (2003) found oxytocin (OT) reduced this in ASD, suggesting a possible link to OCD. Though OT might be expected to be low, Humble et al. (2013) found higher OT levels in severe OCD cases, possibly due to upregulation (fewer OT receptors → more OT released). Cappi et al. (2016) found increased methylation of the OXTR gene (which codes for OT receptors) in OCD patients, suggesting OT irregularities may raise vulnerability.
biochemical strength
A strength of the biological explanation is that it led to drug treatments like clomipramine, which helped Rapoport’s patient Charles return to school. While some oppose drug use, especially in children, such treatments help those without access to therapy. However, Charles developed tolerance within a year, showing biological treatments may only offer short-term relief.
biochemical reductionism vs holism
A weakness of the biochemical explanation is that it’s reductionist, ignoring environmental factors—e.g., compulsions are negatively reinforced by anxiety relief, suggesting behavioural therapy could help. However, it may mislead people to think only meds work. That said, biochemical explanations can be holistic through epigenetics—e.g., methylation of the OXTR gene (Cappi et al., 2016) shows how life events can alter neurotransmission, explaining why people respond differently at different life stages.
psychological explanations
cognitive thinking error
behavioural operant conditioning
psychodynamic
cognitive (thinking error)
Passing thoughts: Avg person has ~6,000/day (Tseng & Poppenk, 2020).
OCD & thought significance: People with OCD struggle to dismiss certain thoughts, believing all thoughts are meaningful and must have a reason.
Thinking errors in OCD turn passing thoughts into obsessions:
Overestimation of personal responsibility: Belief that you alone must prevent harm to self or others → leads to compulsions like checking, washing, cleaning.
Thought-Action Fusion (TAF):
Belief that thinking about an act increases the chance of doing it.
Belief that imagining an event makes it more likely to happen.
Cognitive view: Obsessional thinking comes not from the thought itself, but from how it’s labelled and interpreted.
E.g., a thought is seen as shameful/disgusting → person believes they are shameful/disgusting (dispositional attribution).
behavioural operant conditioning
obsessive thoughts turn to compulsive actions > ope conditioning
compulsive behaviours develop as they help to reduce neg feelings such as anxiety fear guilt shame associated w thinking errors
actions taken to reduce these neg emotions reinforced bc male u feel better
behaviours more likely
occur in non clinical samples
like rituals in sports b4 major events
believing failing to conduct leads to neg outcomes
psychodynamic
Freud’s theory: OCD arises from unconscious conflicts shaped by childhood experiences, especially during the anal stage of psychosexual development (~toilet training age).
Conflict between id and ego:
The id produces obsessive, unacceptable urges.
The ego tries to manage these through defence mechanisms (e.g., compulsions).
Toilet training tension:
Anally expulsive (messy, careless): child rebels by soiling to regain control.
Anally retentive (tidy, controlling): child withholds to avoid punishment/gain control.
Fixation: If conflict remains unresolved, the child becomes ‘stuck’ in this stage → personality shaped by anal characteristics.
Result in adulthood:
Id-driven obsessive thoughts → threaten ego’s stability.
Ego responds with compulsive behaviours (e.g., cleaning, tidiness) as defence against anxiety from early trauma.
eval of psych explanations
experimental evidence
heightened sense of personal responsibility increases urge to cehck
30 people w checking type OCD asked to turn stove on and off
in comparison to control group they self reported less urge to check
less distress when told that they would not be held responsible for any neg outcomes
lopatka and rachman 1995
supports the idea that thinking errors may have a causal role in OCD development
this said behaviour may have been affected by demand characteristics as it was a repeated measures design
ps may have felt more anxious than usual as being watched as part of experiment
psych explanation idiographic vs nomothetic
supported by idiographic research
freud 1909 the rat man
intrusive thoughts = gnawed by rats
scared father and gf also will be
ritualistic counting
symptoms improved when freud helped bro recover memroies of seual desire and repressed hatred of father for stopping him from being w gf
nomothetic research like looking for trends in bigger gros can easily lose sight of personal context in which symptoms experienced
less helpful in explaining atypical cases
psych explanation nature vs nurture
WEAKNESS
failure to acknowledge role of nature in dev of OCD
thobois et al 2004
OCD in man
surgery to remove blood clot from caudate nucleus
three brain structures of worry circuit
worry circuit abnormal in OCD
man no symptom b4 surgery to csn support importance of the structure in inhibiting compulsuve urges
can infer that anything interfering w functioning of brain structure including genetic factors may increase vulneraility to OCD and psych theories usually ignore that
psych explanation individual and situational
STRENGTH
explain individual diffs that lead to some developing OCD and some not
cognitive suggests some people more prone to thinking errors
psychodynamic helps undrerstand the obsessions around forbidden taboos that reflect the id’s socially unacceptable desires
able to explain obsessions w clealiness and neatness in terms of fixation in the anal stge
individual > causes of disorder as relates to relatively stable personal traits
