Animal hoarding is keeping a higher-than-usual number of animals as domestic pets without ability to properly house or care for them, while at the same time denying this inability. Compulsive hoarding can be characterized as a symptom of mental disorder rather than deliberate cruelty towards animals. Hoarders are deeply attached to their pets and find it extremely difficult to let the pets go. They typically cannot comprehend that they are harming their pets by failing to provide them with proper care. Hoarders tend to believe that they provide the right amount of care for them. The American Society for the Prevention of Cruelty to Animals provides a "Hoarding Prevention Team", which works with hoarders to help them attain a manageable and healthy number of pets.

Another human health issue caused by animal hoarding is the risk of zoonotic diseases. Defined as "human diseases acquired from or transmitted to any other vertebrate animal", zoonotic diseases can often be lethal and in all cases constitute a serious public health concern. Examples of well-known zoonotic diseases include bubonic plague, influenza, and rabies. Common domesticated animals constitute a large portion of animals carrying zoonoses, and as a result, humans involved in animal hoarding situations are at particular risk of contracting disease. Zoonoses that may arise in hoarding situations—through vectors such as dog, cat, or rat bites—include rabies, salmonellosis, catscratch fever, hookworm, and ringworm. One zoonosis of special concern is toxoplasmosis, which can be transmitted to humans through cat feces or badly-prepared meat, and is known to cause severe birth defects or stillbirth in the case of infected pregnant women. The risk of zoonotic diseases is amplified by the possibility of community epidemics.

Obsessive-compulsive disorders are treated with various serotonergic antidepressants including the tricyclic antidepressant clomipramine and various SSRI medications. With existing drug therapy, OCD symptoms can be controlled, but not cured. Several of these compounds (including paroxetine, which has an FDA indication) have been tested successfully in conjunction with OCD hoarding.

Not only are there significant health risks associated with compulsive hoarding, but scientists are also trying to pinpoint how significant the interference is with occupational and social functioning in a hoarder's daily life. In a pool of compulsive hoarders, 42% found their behavior problematic to the 63% of their family and friends who saw the behavior as problematic. The findings suggest that individuals who hoard may exhibit impaired sensitivity to their own and others’ emotions, and conversely, relate the world around them by forming attachments to possessions rather than to people. Lower emotional intelligence among hoarding patients may also impact their ability to discard and organize their possessions. With such detrimental characteristics, comprehensive research has been performed to find a cure. Although this is ongoing research, most investigations have found that only a third of patients who hoard show an adequate response to these medications and therapeutic interventions.

With the modifications to the DSM, insurance coverage for treatments will change as well as special education programs.

Digital hoarding (also known as e-hoarding) is excessive acquisition and reluctance to delete electronic material no longer valuable to the user. The behavior includes the mass storage of digital artifacts and the retainment of unnecessary or irrelevant electronic data. The term is increasingly common in pop culture, used to describe the habitual characteristics of compulsive hoarding, but in cyberspace. As with physical space in which excess items are described as "clutter" or "junk," excess digital media is often referred to as "digital clutter."

The most common methods for the treatment of specific phobias are systematic desensitization and in vivo or exposure therapy.

Treatment involves becoming conscious of the addiction through studying, therapy, group work, etc...

Research done by Michel Lejoyeux and Aviv Weinstein suggests that the best possible treatment for CB is through cognitive behavioral therapy. They suggest that a patient first be "evaluated for psychiatric comorbidity, especially with depression, so that appropriate pharmacological treatment can be instituted." Their research indicates that patients who received cognitive behavioral therapy over 10 weeks had reduced episodes of compulsive buying and spent less time shopping as opposed to patients who did not receive this treatment (251).

Lejoyeux and Weinstein also write about pharmacological treatment and studies that question the use of drugs on CB. They declare "Few controlled studies have assessed the effects of pharmacological treatment on compulsive buying, and none have shown any medication to be effective" (252). The most effective treatment is to attend therapy and group work in order to prevent continuation of this addiction.

Selective serotonin reuptake inhibitors such as fluvoxamine and citalopram may be useful in the treatment of CBD, although current evidence is mixed. Opioid antagonists such as naltrexone and nalmefene are promising potential treatments for CBD. A review concluded that evidence is limited and insufficient to support their use at present, however. Naltrexone and nalmefene have also shown effectiveness in the treatment of gambling addiction, an associated disorder.

Compulsive decluttering is a pattern of behavior that is characterized by an excessive desire to discard objects in one's home and living areas. Other terms for such behavior includes obsessive compulsive spartanism. The homes of compulsive declutterers are often empty. It is the antonym of compulsive hoarding.

The consequences of oniomania, which may persist long after a spree, can be devastating, with marriages, long-term relationships, and jobs all feeling the strain. Further problems can include ruined credit history, theft or defalcation of money, defaulted loans, general financial trouble and in some cases bankruptcy or extreme debt, as well as anxiety and a sense of life spiraling out of control. The resulting stress can lead to physical health problems and ruined relationships, or even suicide.

Bibliomania is not to be confused with bibliophilia, which is the usual love of books and is not considered a clinical psychological disorder.

Other abnormal behaviours involving books include book-eating (bibliophagy), compulsive book-stealing (bibliokleptomania), and book-burying (bibliotaphy).

Digital clutter is the term often used to describe the resulting (digital) artefacts of digital hoarding, but it should not be understood as exclusively the result of hoarding. Digital clutter can be created as a side-effect of high occurrences of another user activity, such as the computer desktop icons created through frequent installation of applications. In such a case the clutter does not reflect the user's intent to hoard.

Housekeeping is the term often used to refer to the activity by which digital clutter moves out of the 'clutter' designation, either by being thrown away, or by the recognition of its importance, thus no longer making it part of the 'clutter'.

Systematic desensitization therapy was introduced by Joseph Wolpe in 1958 and employs relaxation techniques with imagined situations. In a controlled environment, usually the therapist's office, the patient will be instructed to visualize a threatening situation (i.e., being in the same room with a dog). After determining the patient's anxiety level, the therapist then coaches the patient in breathing exercises and relaxation techniques to reduce their anxiety to a normal level. The therapy continues until the imagined situation no longer provokes an anxious response.

This method was use in the above-mentioned study done by Drs. Hoffmann and Human whereby twelve female students at the Arcadia campus of Technikon Pretoria College in South Africa were found to possess symptoms of cynophobia. These twelve students were provided with systematic desensitization therapy one hour per week for five to seven weeks; after eight months, the students were contacted again to evaluate the effectiveness of the therapy. Final results indicated the study was fairly successful with 75% of the participants showing significant improvement eight months after the study.

However, in his book, "Virtual Reality Therapy for Anxiety Disorders", Dr. Wiederhold questions the effectiveness of systematic desensitization as the intensity of the perceived threat is reliant on the patient's imagination and could therefore produce a false response in regards to the patient's level of anxiety. His research into recent technological developments has made it possible to integrate virtual reality into systematic desensitization therapy in order to accurately recreate the threatening situation. At the time of publication, there had been no studies done to determine its effectiveness.

The naturally occurring sugar inositol has been suggested as a treatment for OCD.

Nutrition deficiencies may also contribute to OCD and other mental disorders. Vitamin and mineral supplements may aid in such disorders and provide nutrients necessary for proper mental functioning.

μ-Opioids, such as hydrocodone and tramadol, may improve OCD symptoms. Administration of opiate treatment may be contraindicated in individuals concurrently taking CYP2D6 inhibitors such as fluoxetine and paroxetine.

Much current research is devoted to the therapeutic potential of the agents that affect the release of the neurotransmitter glutamate or the binding to its receptors. These include riluzole, memantine, gabapentin, N-acetylcysteine, topiramate and lamotrigine.

Compulsive behavior is defined as performing an act persistently and repetitively without it necessarily leading to an actual reward or pleasure. Compulsive behaviors could be an attempt to make obsessions go away. The act is usually a small, restricted and repetitive behavior, yet not disturbing in a pathological way. Compulsive behaviors are a need to reduce apprehension caused by internal feelings a person wants to abstain from or control. A major cause of the compulsive behaviors is said to be obsessive–compulsive disorder (OCD). "The main idea of compulsive behavior is that the likely excessive activity is not connected to the purpose to which it appears directed." Furthermore, there are many different types of compulsive behaviors including, shopping, hoarding, eating, gambling, trichotillomania and picking skin, checking, counting, washing, sex, and more. Also, there are cultural examples of compulsive behavior.

Compulsive talking goes beyond the bounds of what is considered to be a socially acceptable amount of talking. The two main factors in determining if someone is a compulsive talker are talking in a continuous manner, only stopping when the other person starts talking, and others perceiving their talking as a problem. Personality traits that have been positively linked to this compulsion include assertiveness, willingness to communicate, self-perceived communication competence, and neuroticism. Studies have shown that most people who are talkaholics are aware of the amount of talking they do, are unable to stop, and do not see it as a problem.

Zoophobia or animal phobia is a class of specific phobias to particular animals, or an irrational fear or even simply dislike of any non-human animals.

Examples of specific zoophobias would be entomophobias, such as that of bees (apiphobia). Fears of spiders (arachnophobia), birds (ornithophobia) and snakes (ophidiophobia) are also common. See the article at -phobia for the list of various phobias. Sigmund Freud mentioned that an animal phobia is one of the most frequent psychoneurotic diseases among children.

Zoophobia is not the sensible fear of dangerous or threatening animals, such as wild dogs (example: wolves, dingoes, and coyotes), big cats, bears or venomous snakes. It is a phobia of animals that causes distress or dysfunction in the individual's everyday life.

Bibliomania can be a symptom of obsessive–compulsive disorder which involves the collecting or even hoarding of books to the point where social relations or health are damaged.

In the case of pathological gambling, along with fluvoxamine, clomipramine has been shown effective in the treatment, with reducing the problems of pathological gambling in a subject by up to 90%. Whereas in trichotillomania, the use of clomipramine has again been found to be effective, fluoxetine has not produced consistent positive results. Fluoxetine, however, has produced positive results in the treatment of pathological skin picking disorder, although more research is needed to conclude this information. Fluoxetine has also been evaluated in treating IED and demonstrated significant improvement in reducing frequency and severity of impulsive aggression and irritability in a sample of 100 subjects who were randomized into a 14-week, double-blind study. Despite a large decrease in impulsive aggression behavior from baseline, only 44% of fluoxetine responders and 29% of all fluoxetine subjects were considered to be in full remission at the end of the study. Paroxetine has shown to be somewhat effective although the results are inconsistent. Another medication, escitalopram, has shown to improve the condition of the subjects of pathological gambling with anxiety symptoms. The results suggest that although SSRIs have shown positive results in the treatment of pathological gambling, inconsistent results with the use of SSRIs have been obtained which might suggest a neurological heterogeneity in the impulse-control disorder spectrum.

Impulse-control disorders have two treatment options: psychosocial and pharmacological. Treatment methodology is informed by the presence of comorbid conditions.

Species dysphoria is the experience of dysphoria, sometimes including clinical lycanthropy (delusion or hallucination of one's self as an animal) and dysmorphia (excessive concern over one's body image), associated with the feeling that one's body is of the wrong species. Earls and Lalumière (2009) describe it as "the sense of being in the wrong (species) body... a desire to be an animal". Outside of psychological literature, the term is common within the otherkin and therian communities. The phenomenon is sometimes experienced in the context of sexual arousal to the image of one's self as an animal.

"Species dysphoria" is informally used mainly in psychological literature to compare the experiences of some individuals to those in the transgender community. Otherkin and therian communities have also used it to describe their experiences.

In a 2008 study by Gerbasi "et al.", 46% of people surveyed who identified as being in the furry fandom, (usually defined as a person who enjoys anthropomorphic animals, occasionally to an almost obsessive degree), answered "yes" to the question "Do you consider yourself to be less than 100% human?" and 41% answered "yes" to the question "If you could become 0% human, would you?" Questions that Gerbasi states as being deliberately designed to draw parallels with gender dysphoria, specifying "a persistent feeling of discomfort" about the human body and the feeling that the person was the "non-human species trapped in a human body", were answered "yes" by 24% and 29% of respondents, respectively. Likewise, these studies support the fact that the therianthropic, otherkin and furry communities are very similar in nature and are often interconnected.

As described by those who experience it, species dysphoria may include sensations of supernumerary phantom limbs associated with the species, such as phantom wings or claws. Species dysphoria involves feelings of being an animal or other creatures "trapped in" a human body and so, is considered different from the traditional definition of clinical lycanthropy, in which the patient believes they have actually been transformed into an animal or have the ability to physically shapeshift. However, some cases that have been labeled as "clinical lycanthropy" actually seem to be cases of species dysphoria, involving persons who have no delusion of transformation but instead have feelings of being in some way a non-human animal, while still acknowledging they possess a human form. Keck "et al." propose a redefinition for clinical lycanthropy that covers species dysphoric behaviours observed in several patients, including verbal reports, "during intervals of lucidity or retrospectively, that he or she was a particular animal" and behaving "in the manner of a particular animal, i.e. howling, growling, crawling on all fours". Keck "et al." describe one patient as a depressed individual who "had always suspected he was a cat" and "laments his lack of fur, stripes and a tail". Except for the persistent feeling of being feline, the patient's "thought processes and perception" were "usually logical".

Treatment for OCPD includes psychotherapy, cognitive behavioral therapy, behavior therapy or self-help. Medication may be prescribed. In behavior therapy, a person with OCPD discusses with a psychotherapist ways of changing compulsions into healthier, productive behaviors. Cognitive analytic therapy is an effective form of behavior therapy.

Treatment is complicated if the person does not accept that they have OCPD, or believes that their thoughts or behaviors are in some sense correct and therefore should not be changed. Medication alone is generally not indicated for this personality disorder. Selective serotonin reuptake inhibitors (SSRIs) may be useful in addition to psychotherapy by helping the person with OCPD be less bogged down by minor details, and to lessen how rigid they are.

People with OCPD are three times more likely to receive individual psychotherapy than people with major depressive disorder. There are higher rates of primary care utilization. There are no known properly controlled studies of treatment options for OCPD. More research is needed to explore better treatment options.

The medications most frequently used are the selective serotonin reuptake inhibitors (SSRIs). Clomipramine, a medication belonging to the class of tricyclic antidepressants, appears to work as well as SSRIs but has a higher rate of side effects.

SSRIs are a second line treatment of adult obsessive compulsive disorder (OCD) with mild functional impairment and as first line treatment for those with moderate or severe impairment. In children, SSRIs can be considered as a second line therapy in those with moderate-to-severe impairment, with close monitoring for psychiatric adverse effects. SSRIs are efficacious in the treatment of OCD; people treated with SSRIs are about twice as likely to respond to treatment as those treated with placebo. Efficacy has been demonstrated both in short-term (6–24 weeks) treatment trials and in discontinuation trials with durations of 28–52 weeks.

In 2006, the National Institute of Clinical and Health Excellence (NICE) guidelines recommended antipsychotics for OCD that does not improve with SSRI treatment. For OCD the evidence for the atypical antipsychotic drugs risperidone and quetiapine is tentative with insufficient evidence for olanzapine. A 2014 review article found two studies that indicated that aripiprazole was "effective in the short-term" and found that "[t]here was a small effect-size for risperidone or anti-psychotics in general in the short-term"; however, the study authors found "no evidence for the effectiveness of quetiapine or olanzapine in comparison to placebo." While quetiapine may be useful when used in addition to an SSRI in treatment-resistant OCD, these drugs are often poorly tolerated, and have metabolic side effects that limit their use. None of the atypical antipsychotics appear to be useful when used alone. Another review reported that no evidence supports the use of first generation antipsychotics in OCD.

A guideline by the APA suggested that dextroamphetamine may be considered by itself after more well supported treatments have been tried.

A crush fetish is a fetish and a paraphilia in which one is sexually aroused when someone crushes objects, food, and sometimes small animals (frequently insects) with their body, usually under their foot, or when crushed oneself. The term soft crush refers to the more common fetish surrounding videos involving inanimate objects (such as food) or small invertebrates (e.g. insects, snails, worms, arachnids) being crushed, while the term hard crush refers to such videos involving larger animals with vertebrae, and arguably more pain-susceptible animals (e.g. reptiles, birds, mammals). The preference could be barefoot, high-heels, flip flops, socks, and so on, depending on the fetishist. Most soft crush fetishists prefer to distinguish themselves from hard crush fetishists, believing that crush films with larger animals give the entire group a bad label.

There are currently no known laws forbidding the crushing of objects and insects, but the production or trade of crush erotica involving live vertebrates is condemned by animal rights activists and is illegal in many countries, including the United States and Great Britain. In the United States, interstate commerce in [hard] crush videos has been illegal since 2010, and many other countries also have banned them.

Some research suggests there is a genetic basis for greed. It is possible people who have a shorter version of the ruthlessness gene (AVPR1a) may behave more selfishly.