sexual function and disorders Flashcards
why is it difficult to study sex behaviours
remains private for most
wide range of specific behaviours
diverse across individuals, cultures, and time
varies within individuals - age, life events, circumstances
how has neural basis been studied for sex behaviours
in rats
sex behaviours - hypothalamus in males
males = medial preoptic area (MPAO) for copulatory behaviours (mounting, intromission, ejaculation)
lesions abolish these behaviours (and can in females where some are also observed)
stimulation of MPAO elicits these behaviours
sex behaviours - hypothalamus in females
females = ventromedial nucleus (VMN) for copulatory behaviours (lordosis)
stimulation of VMN facilitates lordosis in response to a male
Complexity of sexual behaviour beyond neural mechanisms - in humans and mice
yes
complex sensory input and cortical and subcortical systems conveying contextual rewards-related and motivational info
e.g. mice sing to each other
e.g. chemical in tears of juvenile mice deters female mice from them
humans - comparative thinking about sexual behaviour
early studies of human sexual behaviour - Alfred Kinsey
Alfred Kinsey (1940-50s) - the Kinsey Reports
taxonomy of human sexual behaviour (based on interviews)
study of types and frequencies of behaviours in population
→ shocking at the time
early studies of human sexual behaviour - Masters and Johnson
study of human sexual behaviours and disorders in 50s/60s
measured sex and masturbation in a lab
established 4 stage model for human sex behaviour → sexual response cycle
Sexual Response Cycle - 4 stages
desire, plateau, orgasm, resolution
male-female difference –> male orgasm once, women can multiple times
recent studies of human sexual behaviours
refined terminology and identified variability in normal cycles - building off of sexual response cycle - desire, arousal, plateau, orgasm, refraction
attempts to determine neuroanatomical correlates of components of the cycle
3 major components: wanting, liking, learning
fMRI studies of sexual function found differences in brain in difference phases
sexual orientation
relates to biological sex, gender identity, and sexual behaviour
sexual identity = aspects of both gender identity and sexual orientation
animal models of sexual orientation
interference with sexual differentiation (e.g. blocking hormones, lesioning hypothalamic nuclei) can lead to displays of behaviours related with opposite sex and same-sex preferences
cannot translate well to humans - is it valid in studying sexual orientation
FBOE
fraternal birth order effect
more older brothers = boys more likely to be gay
15-29% of gay men follow this effect
remains across different cultures
older sisters or younger siblings have no effect on sexual orientation - just older brothers
effect remains if older brothers raised in different households but doesn’t remain with older step brothers or adopted brothers
implies effect relates to maternal factors
maternal immunization hypothesis
* antibodies in mother after having a boy which pass on to next child and effect sexual orientation
meta-analysis found evidence was not specific to men and effect size varied greatly - small study effects
sexual orientation research - perinatal hormone exposure
limited evidence that perinatal hormone exposure can modulate same-sex/opposite sex preferences
sexual orientation research - hypothalamic nuclei
some evidence that hypothalamic nuclei may play a role in sexual preference → size differences of nuclei in hetero vs homosexual men and women
sexual orientation research - family/twin studies
some family/twin studies for moderate genetic influence on sexual orientation
up to 40% of variance in sexual orientation of males and 20% of variance in sexual orientation of females may have genetic basis
sexual orientation research - genetic markers
specific genetic markers associated with sexual orientation
determined none were predictive of sexual orientation - no “gay gene”
therefore genetic component is multidimensional and complex
defining what is normal - different measures
deviation from statistical norms
deviation from social norms
distress
deficits in normal function
defining what is normal - deviation from statistical norm
somewhat arbitrary in terms of usefulness and classification
relies on extensive and accurate data - hard to obtain
cross-cultural granularity
ultimately remains subjective
defining what is normal - deviation from social norms
influence on social judgement
socially normal isn’t always adaptive/functional
subjective perception of norms can differ from actual norms
cultural and historical variation - political influences
circularity → norms create pathology as well as define it
defining what is normal - distress
focus on emotional/psychological well-being
persistence/frequency of distress may be important
needs awareness and acknowledgement that some individuals don’t experience distress
social norms and protection of others - laws
defining what is normal - deficits in normal function
focus on social, interpersonal, occupational functioning
e.g. can’t develop/maintain loving relationship
some responses can have reasonable basis - e.g. abuse - and so need to avoid pathologising
can cut across individual life choices
ignore individual experience/impact
interacts with social norms
define sexual dysfunction
relates to problems with experiencing the human sexual response cycle
define paraphilic disorders
relates to inappropriate activation of the human sexual response cycle
“Any intense and persistent sexual interest, other than sexual interest in genital stimulation or preparatory fondling with phenotypically normal physically mature, consenting human partners” - DSM-V
define gender dysphoria
unhappiness due to perceived gender differing from assigned gender
sexual dysfunction - typeswith cycle
types categorised according to phases of human sexual response cycle:
desire → male hypoactive sexual desire disorder
plateau → female sexual interest/desire disorder, erectile disorder
orgasm → female orgasmic disorder, delayed ejaculation, early ejaculation
resolution → sexual pain disorders
sexual dysfunction: diagnosis, risk factors, causes, and treatments
diagnosis - must be impact on subjective distress and functioning (e.g. relationships) with persistent and recurrent symptoms. more common in females (may be gender bias in reporting)
risk factors = gender related, health conditions, sexual abuse
causes = psychological or biological can be hard to determine (concerns with over pathologising inter and intra individual differences)
treatments = symptom focussed, psychotherapy or drugs/devices
paraphilic disorders - types in 3 categories (2,4,2)
not directed at another person:
fetishistic disorder
transvestic disorder
directed at non-consenting person:
exhibitionistic disorder
frotteuristic disorder (touching)
pedophilic disorder
voyeuristic disorder
involves experiencing or inflicting suffering:
sexual masochism disorder
sexual sadism disorder
ideas of how the law interacts with this
paraphilic disorder - diagnosis, risk factors, causes, treatments
diagnosis = satisfaction must entail either distress/harm to individual or another person
risk factors = being male, hypersexuality, for paedophilia = past sexual abuse, attachment issues, substance abuse comorbidity
causes = very little understood - possible psychodynamic but could also be cognitive or biological (most research done on paedophilic disorder
treatments = behavioural techniques, cognitive therapies, hormonal and drug treatments
gender dysphoria - diagnosis and incidence
previously called gender identity disorder
diagnosis = marked and persistent cross-gender identification, significant distress/impairment, lack of physical intersex condition (other treatments for this)
can be diagnoses in children - though most wont have a condition as adults
incidence estimates vary - relatively rate, 0.01% males and even rarer in females - recent evidence for 1% of population experiencing some level of gender incongruency
comorbid with anxiety and depression
gender dysphoria - psychobiological model (and issues)
neurobiological basis which is closely associated with interaction with external world
introduced concept of brain gender
chromosomal gender -> phenotypic gender -> brain gender -> experienced gender
issues:
* goes against evidence for no male/female brain difference
* downplays environmental and brain plasticity aspects
* binary nature
* causality regarding brain differences isn’t well established in evidence
gender dysphoria - risk factors and causes
evidence base and understanding relatively weak
some evidence indicates that paternal relationship (for males) and childhood abuse (for females) may be factors
little support for notion that parental attitudes or behaviours play a role
biological factors may include in-utero hormone exposure
mixed evidence for differences in brain structures
evidence from twin studies for heritability, though no single gene has been found
gender dysphoria - treatments
psychological treatments (behavioural and cognitive) - some success but clients often resistant (understandably)
gender reassignment surgery – often leads to satisfactory outcomes but may not alleviate other psychological co-morbidities
