A woman is said to have primary vaginismus when she is unable to have penetrative sex or experience vaginal penetration without pain. It is commonly discovered in teenage girls and women in their early twenties, as this is when many girls and young women first attempt to use tampons, have penetrative sex, or undergo a Pap smear. Women with vaginismus may be unaware of the condition until they attempt vaginal penetration. A woman may be unaware of the reasons for her condition.

A few of the main factors that may contribute to primary vaginismus include:

- a condition called vulvar vestibulitis syndrome, more or less synonymous with focal vaginitis, a so-called sub-clinical inflammation, in which no pain is perceived until some form of penetration is attempted

- urinary tract infections

- vaginal yeast infections

- sexual abuse, rape, other sexual assault, or attempted sexual abuse or assault

- knowledge of (or witnessing) sexual or physical abuse of others, without being personally abused

- domestic violence or similar conflict in the early home environment

- fear of pain associated with penetration, particularly the popular misconception of "breaking" the hymen upon the first attempt at penetration, or the idea that vaginal penetration will inevitably hurt the first time it occurs

- chronic pain conditions and harm-avoidance behaviour

- any physically invasive trauma (not necessarily involving or even near the genitals)

- generalized anxiety

- stress

- negative emotional reaction towards sexual stimulation, e.g. disgust both at a deliberate level and also at a more implicit level

- strict conservative moral education, which also can elicit negative emotions

Primary vaginismus is often idiopathic.

Vaginismus has been classified by Lamont according to the severity of the condition. Lamont describes four degrees of vaginismus: In first degree vaginismus, the patient has spasm of the pelvic floor that can be relieved with reassurance. In second degree, the spasm is present but maintained throughout the pelvis even with reassurance. In third degree, the patient elevates the buttocks to avoid being examined. In fourth degree vaginismus (also known as grade 4 vaginismus), the most severe form of vaginismus, the patient elevates the buttocks, retreats and tightly closes the thighs to avoid examination. Pacik expanded the Lamont classification to include a fifth degree in which the patient experiences a visceral reaction such as sweating, hyperventilation, palpitations, trembling, shaking, nausea, vomiting, losing consciousness, wanting to jump off the table, or attacking the doctor. The Lamont classification continues to be used to the present and allows for a common language among researchers and therapists.

A simplified and more versatile version of the classification includes symptoms that vary over four ranges. The first involves minor discomfort that may diminish during intercourse. In the second range, burning and tightness persist. In the third, entry and movement are painful, and in the fourth penetration is impossible and forced entry is extremely painful.

Although the pubococcygeus muscle is commonly thought to be the primary muscle involved in vaginismus, Pacik identified two additionally-involved spastic muscles in treated patients under sedation. These include the entry muscle (bulbocavernosum) and the mid-vaginal muscle (puborectalis). Spasm of the entry muscle accounts for the common complaint that patients often report when trying to have intercourse: "It's like hitting a brick wall".

Vaginismus, sometimes called vaginism, is a condition that affects a woman's ability to engage in vaginal penetration, including sexual intercourse, manual penetration, insertion of tampons or menstrual cups, and the penetration involved in gynecological examinations (pap tests). This is the result of an involuntary vaginal muscle spasm, which makes any kind of vaginal penetration painful or impossible. While there is a lack of evidence to definitively identify which muscle is responsible for the spasm, the pubococcygeus muscle, sometimes referred to as the "PC muscle", is most often suggested. Other muscles such as the levator ani, bulbocavernosus, circumvaginal, and perivaginal muscles have also been suggested.

A woman with vaginismus does not consciously control the spasm. The vaginismic reflex can be compared to the response of the eye shutting when an object comes towards it. The severity of vaginismus, as well as the pain during penetration (including sexual penetration), varies from woman to woman.

Post-orgasmic diseases cause symptoms shortly after orgasm or ejaculation. Post-coital tristesse (PCT) is a feeling of melancholy and anxiety after sexual intercourse that lasts for up to two hours. Sexual headaches occur in the skull and neck during sexual activity, including masturbation, arousal or orgasm.

In men, postorgasmic illness syndrome (POIS) causes severe muscle pain throughout the body and other symptoms immediately following ejaculation. The symptoms last for up to a week. Some doctors speculate that the frequency of POIS "in the population may be greater than has been reported in the academic literature", and that many POIS sufferers are undiagnosed.

Symptomology of POIS may present as adrenergic-type presentation; Rapid breathing, paraesthesia, palpitations, headaches, aphasia, nausea, itchy eyes, fever, muscle pain/weakness and fatigue.

From the onset of orgasm, symptoms can persist for up to a week in patients.

The aetiology of this condition is unknown, however it is believed to be a pathology of either the immune system or autonomic nervous systems. It is defined as a rare disease by the NIH but the prevalence is unknown. It is not thought to be psychiatric in nature, but it may present as anxiety relating to coital activities and thus may be incorrectly diagnosed as such. There is no known cure or treatment.

Dhat Syndrome is another condition which occurs in men. It is a culture-bound syndrome which causes anxious and dysphoric mood after sex, but is distinct from the low-mood and concentration problems (acute aphasia) seen in Post-Orgasm illness syndrome *

Pelvic floor dysfunction can be an underlying cause of sexual dysfunction in both women and men, and is treatable by physical therapy.

There are a number of causes of functional incontinence. These include confusion, dementia, poor eyesight, impaired or dexterity or unwillingness to use the toilet due to depression or anxiety. Functional incontinence is more common in elderly people as many of the causes are associated with conditions that affect people as they age. For example, a person with Alzheimer's disease may not plan well enough to reach a bathroom in time or may not remember how to get to the bathroom.

Anismus (or dyssynergic defecation) refers to the failure of the normal relaxation of pelvic floor muscles during attempted defecation.

Anismus can occur in both children and adults, and in both men and women (although it is more common in women). It can be caused by physical defects or it can occur for other reasons or unknown reasons. Anismus that has a behavioral cause could be viewed as having similarities with parcopresis, or psychogenic fecal retention.

Symptoms include tenesmus (the sensation of incomplete emptying of the rectum after defecation has occurred) and constipation. Retention of stool may result in fecal loading (retention of a mass of stool of any consistency) or fecal impaction (retention of a mass of hard stool). This mass may stretch the walls of the rectum and colon, causing megarectum and/or megacolon, respectively. Liquid stool may leak around a fecal impaction, possibly causing degrees of liquid fecal incontinence. This is usually termed encopresis or soiling in children, and fecal leakage, soiling or liquid fecal incontinence in adults.

Anismus is usually treated with dietary adjustments, such as dietary fiber supplementation. It can also be treated with a type of biofeedback therapy, during which a sensor probe is inserted into the person's anal canal in order to record the pressures exerted by the pelvic floor muscles. These pressures are visually fed back to the patient via a monitor who can regain the normal coordinated movement of the muscles after a few sessions.

Some researchers have suggested that anismus is an over-diagnosed condition, since the standard investigations or digital rectal examination and anorectal manometry were shown to cause paradoxical sphincter contraction in healthy controls, who did not have constipation or incontinence. Due to the invasive and perhaps uncomfortable nature of these investigations, the pelvic floor musculature is thought to behave differently than under normal circumstances. These researchers went on to conclude that paradoxical pelvic floor contraction is a common finding in healthy people as well as in people with chronic constipation and stool incontinence, and it represents a non-specific finding or laboratory artifact related to untoward conditions during examination, and that true anismus is actually rare.

Functional incontinence is a form of urinary incontinence in which a person is usually aware of the need to urinate, but for one or more physical or mental reasons they are unable to get to a bathroom. The loss of urine can vary, from small leakages to full emptying of the bladder.

Paradoxical anal contraction during attempted defecation in constipated patients was first described in a paper in 1985, when the term anismus was first used. The researchers drew analogies to a condition called vaginismus, which involves paroxysmal (sudden and short lasting) contraction of pubococcygeus (another muscle of the pelvic floor). These researchers felt that this condition was a spastic dysfunction of the anus, analogous to ‘vaginismus’. However, the term anismus implies a psychogenic etiology, which is not true although psychological dysfunction has been described in these patients. Hence:

Latin "ani" - "of the anus"

Latin "spasmus" - "spasm"

Many terms have been used synonymously to refer to this condition, some inappropriately. The term "anismus" has been criticised as it implies a psychogenic cause. As stated in the Rome II criteria, the term "dyssynergic defecation" is preferred to "pelvic floor dyssynergia" because many patients with dyssynergic defecation do not report sexual or urinary symptoms, meaning that only the defecation mechanism is affected.

Other synonyms include:

- Dyskinetic puborectalis

- Puborectalis syndrome

- Paradoxical puborectalis

- Nonrelaxing puborectalis

- Paradoxal puborectal contraction

- Spastic pelvic floor syndrome,

- Anal sphincter dyssynergia

- Paradoxical pelvic floor contraction

In the DSM-5, male hypoactive sexual desire disorder is characterized by "persistently or recurrently deficient (or absent) sexual/erotic thoughts or fantasies and desire for sexual activity", as judged by a clinician with consideration for the patient's age and cultural context. Female sexual interest/arousal disorder is defined as a "lack of, or significantly reduced, sexual interest/arousal", manifesting as at least three of the following symptoms: no or little interest in sexual activity, no or few sexual thoughts, no or few attempts to initiate sexual activity or respond to partner's initiation, no or little sexual pleasure/excitement in 75%-100% of sexual experiences, no or little sexual interest in internal or external erotic stimuli, and no or few genital/nongenital sensations in 75%-100% of sexual experiences.

For both diagnoses, symptoms must persist for at least six months, cause clinically significant distress, and not be better explained by another condition. Simply having lower desire than one's partner is not sufficient for a diagnosis. Self-identification of a lifelong lack of sexual desire as asexuality precludes diagnosis.

Low sexual desire alone is not equivalent to HSDD because of the requirement in HSDD that the low sexual desire causes marked distress and interpersonal difficulty and because of the requirement that the low desire is not better accounted for by another disorder in the DSM or by a general medical problem. It is therefore difficult to say exactly what causes HSDD. It is easier to describe, instead, some of the causes of low sexual desire.

In men, though there are theoretically more types of HSDD/low sexual desire, typically men are only diagnosed with one of three subtypes.

- Lifelong/generalised: The man has little or no desire for sexual stimulation (with a partner or alone) and never had.

- Acquired/generalised: The man previously had sexual interest in his present partner, but lacks interest in sexual activity, partnered or solitary.

- Acquired/situational: The man was previously sexually interested in his present partner but now lacks sexual interest in this partner but has desire for sexual stimulation (i.e. alone or with someone other than his present partner.)

Though it can sometimes be difficult to distinguish between these types, they do not necessarily have the same cause. The cause of lifelong/generalized HSDD is unknown. In the case of acquired/generalized low sexual desire, possible causes include various medical/health problems, psychiatric problems, low levels of testosterone or high levels of prolactin. One theory suggests that sexual desire is controlled by a balance between inhibitory and excitatory factors. This is thought to be expressed via neurotransmitters in selective brain areas. A decrease in sexual desire may therefore be due to an imbalance between neurotransmitters with excitatory activity like dopamine and norepinephrine and neurotransmitters with inhibitory activity, like serotonin. The, New York-based, "New View Campaign" organization has expressed skepticism about too much emphasis on explanations based on neurotransmitters because emphasis on such explanations have been made largely by "educational" efforts funded by Boehringer-Ingelheim while it was attempting to get the FDA to approve a drug affecting neurotransmitters for treatment for HSDD. Low sexual desire can also be a side effect of various medications. In the case of acquired/situational HSDD, possible causes include intimacy difficulty, relationship problems, sexual addiction, and chronic illness of the man’s partner. The evidence for these is somewhat in question. Some claimed causes of low sexual desire are based on empirical evidence. However, some are based merely on clinical observation. In many cases, the cause of HSDD is simply unknown.

There are some factors that are believed to be possible causes of HSDD in women. As with men, various medical problems, psychiatric problems (such as mood disorders), or increased amounts of prolactin can cause HSDD. Other hormones are believed to be involved as well. Additionally, factors such as relationship problems or stress are believed to be possible causes of reduced sexual desire in women. According to one recent study examining the affective responses and attentional capture of sexual stimuli in women with and without HSDD, women with HSDD do not appear to have a negative association to sexual stimuli, but rather a weaker positive association than women without HSDD

Irritable Bowel Syndrome (IBS),

Fibromyalgia (FMS),

Chronic Fatigue Syndrome (CFS),

Chronic Pelvic Pain (CPP),

Interstitial Cystitis (IC),

Temporomandibular Joint Pain (TMJ), Functional Neurological Symptom Disorder (FNsD),

Non-Cardiac Chest Pain (NCCP),

Post-Traumatic Stress Disorder (PTSD),

Dysuria (Pain On Urination),

and Multiple Chemical Sensitivity

A functional disorder is a medical condition that impairs the normal function of a bodily process, but where every part of the body looks completely normal under examination, dissection or even under a microscope. This stands in contrast to a structural disorder (in which some part of the body can be seen to be abnormal) or a psychosomatic disorder (in which symptoms are caused by psychological or psychiatric illness). Definitions vary somewhat between fields of medicine.

Generally, the mechanism that causes a functional disorder is unknown, poorly understood, or occasionally unimportant for treatment purposes. The brain or nerves are often believed to be involved. It is common that a person with one functional disorder will have others.

Chronic idiopathic constipation is similar to constipation-predominant irritable bowel syndrome (IBS-C); however, people with CIC do not have other symptoms of IBS, such as abdominal pain. Diagnosing CIC can be difficult as other syndromes must be ruled out as there is no physiological cause for CIC. Doctors will typically look for other symptoms, such as blood in stool, weight loss, low blood count, or other symptoms.

To be considered functional constipation, symptoms must be present at least a fourth of the time.

Possible causes are:

- Anismus

- Descending perineum syndrome

- Other inability or unwillingness to control the external anal sphincter, which normally is under voluntary control

- A poor diet

- An unwillingness to defecate

- Nervous reactions, including prolonged and/or chronic stress and anxiety, that close the internal anal sphincter, a muscle that is not under voluntary control

- Deeper psychosomatic disorders which sometimes affect digestion and the absorption of water in the colon

There is also possibility of presentation with other comorbid symptoms such as headache, especially in children.

Conversion disorder begins with some stressor, trauma, or psychological distress. Usually the physical symptoms of the syndrome affect the senses or movement. Common symptoms include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. These symptoms are attributed to conversion disorder when a medical explanation for the afflictions cannot be found. Symptoms of conversion disorder usually occur suddenly. Conversion disorder is typically seen in individuals aged 10 to 35, and affects between 0.011% and 0.5% of the general population.

Conversion disorder can present with motor or sensory symptoms including any of the following:

Motor symptoms or deficits:

- Impaired coordination or balance

- Weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)

- Impairment or loss of speech (hysterical aphonia)

- Difficulty swallowing (dysphagia) or a sensation of a lump in the throat

- Urinary retention

- Psychogenic non-epileptic seizures or convulsions

- Persistent dystonia

- Tremor, myoclonus or other movement disorders

- Gait problems (astasia-abasia)

- Loss of consciousness (fainting)

Sensory symptoms or deficits:

- Impaired vision (hysterical blindness), double vision

- Impaired hearing (deafness)

- Loss or disturbance of touch or pain sensation

Conversion symptoms typically do not conform to known anatomical pathways and physiological mechanisms. It has sometimes been stated that the presenting symptoms tend to reflect the patient's own understanding of anatomy and that the less medical knowledge a person has, the more implausible are the presenting symptoms. However, no systematic studies have yet been performed to substantiate this statement.

There are a great number of symptoms experienced by those with a functional neurological disorder. It is important to note that the symptoms experienced by those with an FND are very real , and should not be confused with malingering, factitious disorders, or Munchausen syndrome. At the same time, the origin of symptoms is complex since it can be associated with physical injury, severe psychological trauma (conversion disorder), and idiopathic neurological dysfunction. The core symptoms are those of motor or sensory function or episodes of altered awareness

- Limb weakness or paralysis

- Blackouts (also called dissociative or non-epileptic seizures/attacks) – these may look like epileptic seizures or faints

- Movement disorders including tremors, dystonia (spasms), myoclonus (jerky movements)

- Visual symptoms including loss of vision or double vision

- Speech symptoms including dysphonia (whispering speech), slurred or stuttering speech

- Sensory disturbance including hemisensory syndrome (altered sensation down one side of the body)

Dysphonia is a broad clinical term which refers to abnormal functioning of the voice. More specifically, a voice can be classified as “dysphonic” when there are abnormalities or impairments in one or more of the following parameters of voice: pitch, loudness, quality, and variability. For example, abnormal pitch can be characterized by a voice that is too high or low whereas abnormal loudness can be characterized by a voice that is too weak or loud. Similarly, a voice that has frequent, inappropriate breaks characterizes abnormal quality while a voice that is monotone (i.e., very flat) or inappropriately fluctuates characterizes abnormal variability. While hoarseness is used interchangeably with the term dysphonia, it is important to note that the two are not synonymous. Hoarseness is merely a subjective term to explain the perceptual quality (or sound) of a dysphonic voice. While hoarseness is a common symptom (or complaint) of dysphonia, there are several other signs and symptoms that can be present such as: breathiness, roughness, and dryness. Furthermore, a voice can be classified as dysphonic when it poses problems in the functional or occupational needs of the individual or is inappropriate for their age or sex.

Conversion disorder presents with symptoms that typically resemble a neurological disorder such as stroke, multiple sclerosis, epilepsy or hypokalemic periodic paralysis. The neurologist must carefully exclude neurological disease, through examination and appropriate investigations. However, it is not uncommon for patients with neurological disease to also have conversion disorder.

In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder, i.e. certain aspects of the presentation that were thought to be rare in neurological disease but common in conversion. The validity of many of these signs has been questioned, however, by a study showing that they also occur in neurological disease. One such symptom, for example, is "la belle indifférence", described in DSM-IV as "a relative lack of concern about the nature or implications of the symptoms". In a later study, no evidence was found that patients with functional symptoms are any more likely to exhibit this than patients with a confirmed organic disease. In DSM-V, "la belle indifférence" was removed as a diagnostic criteria.

Another feature thought to be important was that symptoms tended to be more severe on the non-dominant (usually left) side of the body. There have been a number of theories about this, such as the relative involvement of cerebral hemispheres in emotional processing, or more simply, that it was "easier" to live with a functional deficit on the non-dominant side. However, a literature review of 121 studies established that this was not true, with publication bias the most likely explanation for this commonly held view. Although agitation is often assumed to be a positive sign of conversion disorder, release of epinephrine is a well-demonstrated cause of paralysis from hypokalemic periodic paralysis.

Misdiagnosis does sometimes occur. In a highly influential study from the 1960s, Eliot Slater demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder. Later authors have argued that the paper was flawed, however, and a meta-analysis has shown that misdiagnosis rates since that paper was published are around 4%, the same as for other neurological diseases.

Functional somatic syndrome is characterized by ambiguous, non-specific symptoms that appear in otherwise-healthy populations. Overlap exists in different syndromes, including gastrointestinal issues, pain, fatigue, cognitive difficulties, and sleep difficulties. Some have proposed to group symptoms into clusters or into one general functional somatic disorder given the finding of correlations between symptoms and underlying etiologies.

Functional neurological disorders are a common problem, and are the second most common reason for a neurological outpatient visit after headache/migraine. Dissociative (non-epileptic) seizures account for about 1 in 7 referrals to neurologists after an initial seizure, and functional weakness has a similar prevalence to multiple sclerosis.

Functional constipation, known as chronic idiopathic constipation (CIC), is constipation that does not have a physical (anatomical) or physiological (hormonal or other body chemistry) cause. It may have a neurological, psychological or psychosomatic cause. A person with functional constipation may be healthy, yet has difficulty defecating.

A vaginal obstruction is often caused by an imperforate hymen or, less commonly, a transverse vaginal septum. A sign of vaginal obstruction is hydrocolpos, that is, accumulation of watery fluid within the vagina. It may extend to become "hydrometrocolpos", that is, accumulation of watery fluid within the vagina as well as within the uterus.

Vaginal hypoplasia is the underdevelopment or incomplete development of the vagina. Vaginal hypoplasia can vary in severity from being smaller than normal to being completely absent. The absence of a vagina is a result of vaginal agenesis. Diagnostically, it may look similar to a vaginal obstruction. It is frequently associated with Mayer-Rokitansky-Küstner-Hauser (MRKH) syndrome, in which the most common result is an absent uterus in conjunction with a deformed or missing vagina, despite the presence of normal ovaries and normal external genitalia. It is also associated with cervical agenesis, in which the uterus is present but the uterine cervix is absent.

Voice disorders can be divided into 2 broad categories: organic and functional. The distinction between these broad classes stems from their cause, whereby organic dysphonia results from some sort of physiological change in one of the subsystems of speech (for voice, usually respiration, laryngeal anatomy, and/or other parts of the vocal tract are affected). Conversely, functional dysphonia refers to hoarseness resulting from vocal use (i.e. overuse/abuse). Furthermore, according to ASHA, organic dysphonia can be subdivided into structural and neurogenic; neurogenic dysphonia is defined as impacted functioning of the vocal structure due to a neurological problem (in the central nervous system or peripheral nervous system); in contrast, structural dysphonia is defined as impacted functioning of the vocal mechanism that is caused by some sort of physical change (e.g. a lesion on the vocal folds). Notably, an additional subcategory of functional dysphonia recognized by professionals is psychogenic dysphonia, which can be defined as a type of voice disorder that has no known cause and can be presumed to be a product of some sort of psychological stressors in one’s environment. It is important to note that these types are not mutually exclusive and much overlap occurs. For example, Muscle Tension Dysphonia (MTD) has been found to be a result of many different causes including the following: MTD in the presence of an organic pathology (i.e. organic type), MTD stemming from vocal use (i.e. functional type), and MTD as a result of personality and/or psychological factors (i.e. psychogenic type).

Functional somatic syndrome is a term used to refer to physical symptoms that are poorly explained. It encompass disorders such as chronic fatigue syndrome, fibromyalgia, chronic widespread pain, temporomandibular disorder, irritable bowel syndrome, lower back pain, tension headache, atypical face pain, non-cardiac chest pain, insomnia, palpitation, dyspepsia, and dizziness. General overlap exists between this term, somatization, and somatoform.

Functional weakness is weakness of an arm or leg due to the nervous system not working properly. It is not caused by damage or disease of the nervous system. Patients with functional weakness experience symptoms of limb weakness which can be disabling and frightening such as problems walking or a ‘heaviness’ down one side, dropping things or a feeling that a limb just doesn’t feel normal or ‘part of them’. Functional weakness may also be described as functional neurological symptom disorder (FNsD), Functional Neurological Disorder (FND) or functional neurological symptoms. If the symptoms are caused by a psychological trigger, it may be diagnosed as 'dissociative motor disorder' or conversion disorder (CD).

To the patient and the doctor it often looks as if there has been a stroke or have symptoms of multiple sclerosis. However, unlike these conditions, with functional weakness there is no permanent damage to the nervous system which means that it can get better or even go away completely.

The diagnosis should usually be made by a consultant neurologist so that other neurological causes can be excluded. The diagnosis should be made on the basis of positive features in the history and the examination (such as Hoover's sign). It is dangerous to make the diagnosis simply because tests are normal. Neurologists usually diagnose wrongly about 5% of the time (which is the same for many other conditions.)

Many patients with functional weakness suffer from not being believed. Although psychological factors can be important for a some patients, for the majority of individuals the cause of their weakness has a physical trigger such as a virus, injury or other medical condition. The symptoms of functional weakness are real, and are as disabling and distressing as Multiple Sclerosis or Parkinson's.

The most effective treatment is physiotherapy, however it is also helpful for patients to understand the diagnosis, and some may find CBT helps them to cope with the emotions associated with being unwell. For those with conversion disorder, psychological therapy is key to their treatment as it is emotional or psychological factors which are causing their symptoms.