Question: what is the cause of ocd

Reference:
 Obsessive-compulsive disorder (OCD) Overview Obsessive-compulsive disorder (OCD) features a pattern of unreasonable thoughts and fears (obsessions) that lead you to do repetitive behaviors (compulsions). These obsessions and compulsions interfere with daily activities and cause significant distress. You may try to ignore or stop your obsessions, but that only increases your distress and anxiety. Ultimately, you feel driven to perform compulsive acts to try to ease your stress. Despite efforts to ignore or get rid of bothersome thoughts or urges, they keep coming back. This leads to more ritualistic behavior - the vicious cycle of OCD. OCD often centers around certain themes - for example, a fear of getting contaminated by germs. To ease your contamination fears, you may compulsively wash your hands until they're sore and chapped. If you have OCD, you may be ashamed and embarrassed about the condition, but treatment can be effective. Symptoms Obsessive-compulsive disorder usually includes both obsessions and compulsions. But it's also possible to have only obsession symptoms or only compulsion symptoms. You may or may not realize that your obsessions and compulsions are excessive or unreasonable, but they take up a great deal of time and interfere with your daily routine and social or work functioning. OCD obsessions are repeated, persistent and unwanted thoughts, urges or images that are intrusive and cause distress or anxiety. You might try to ignore them or get rid of them by performing a compulsive behavior or ritual. These obsessions typically intrude when you're trying to think of or do other things. Obsessions often have themes to them, such as: - Fear of contamination or dirt - Needing things orderly and symmetrical - Aggressive or horrific thoughts about harming yourself or others - Unwanted thoughts, including aggression, or sexual or religious subjects Examples of obsession signs and symptoms include: - Fear of being contaminated by touching objects others have touched - Doubts that you've locked the door or turned off the stove - Intense stress when objects aren't orderly or facing a certain way - Images of hurting yourself or someone else that are unwanted and make you uncomfortable - Thoughts about shouting obscenities or acting inappropriately that are unwanted and make you uncomfortable - Avoidance of situations that can trigger obsessions, such as shaking hands - Distress about unpleasant sexual images repeating in your mind OCD compulsions are repetitive behaviors that you feel driven to perform. These repetitive behaviors or mental acts are meant to prevent or reduce anxiety related to your obsessions or prevent something bad from happening. However, engaging in the compulsions brings no pleasure and may offer only a temporary relief from anxiety. You may make up rules or rituals to follow that help control your anxiety when you're having obsessive thoughts. These compulsions are excessive and often are not realistically related to the problem they're intended to fix. As with obsessions, compulsions typically have themes, such as: - Washing and cleaning - Checking - Counting - Orderliness - Following a strict routine - Demanding reassurances Examples of compulsion signs and symptoms include: - Hand-washing until your skin becomes raw - Checking doors repeatedly to make sure they're locked - Checking the stove repeatedly to make sure it's off - Counting in certain patterns - Silently repeating a prayer, word or phrase - Arranging your canned goods to face the same way OCD usually begins in the teen or young adult years. Symptoms usually begin gradually and tend to vary in severity throughout life. Symptoms generally worsen when you experience greater stress. OCD, usually considered a lifelong disorder, can have mild to moderate symptoms or be so severe and time-consuming that it becomes disabling. There's a difference between being a perfectionist - someone who requires flawless results or performance, for example - and having OCD. OCD thoughts aren't simply excessive worries about real problems in your life or liking to have things clean or arranged in a specific way. If your obsessions and compulsions are affecting your quality of life, see your doctor or mental health professional. Causes The cause of obsessive-compulsive disorder isn't fully understood. Main theories include: - Biology. OCD may be a result of changes in your body's own natural chemistry or brain functions. - Genetics. OCD may have a genetic component, but specific genes have yet to be identified. - Environment. Some environmental factors such as infections are suggested as a trigger for OCD, but more research is needed. Risk factors Factors that may increase the risk of developing or triggering obsessive-compulsive disorder include: - Family history. Having parents or other family members with the disorder can increase your risk of developing OCD. - Stressful life events. If you've experienced traumatic or stressful events, your risk may increase. This reaction may, for some reason, trigger the intrusive thoughts, rituals and emotional distress characteristic of OCD. - Other mental health disorders. OCD may be related to other mental health disorders, such as anxiety disorders, depression, substance abuse or tic disorders. Complications Problems resulting from OCD may include, among others: - Health issues, such as contact dermatitis from frequent hand-washing - Inability to attend work, school or social activities - Troubled relationships - Overall poor quality of life - Suicidal thoughts and behavior Diagnosis Steps to help diagnose OCD may include: - Physical exam. This may be done to help rule out other problems that could be causing your symptoms and to check for any related complications. - Lab tests. These may include, for example, a complete blood count (CBC), a check of your thyroid function, and screening for alcohol and drugs. - Psychological evaluation. This includes discussing your thoughts, feelings, symptoms and behavior patterns. With your permission, this may include talking to your family or friends. - Diagnostic criteria for OCD. Your doctor may use criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association. Diagnostic challenges It's sometimes difficult to diagnose OCD because symptoms can be similar to those of obsessive-compulsive personality disorder, anxiety disorders, depression, schizophrenia or other mental health disorders. And it's possible to have both OCD and another mental disorder. Work with your doctor so that you can get the appropriate diagnosis and treatment. Treatment Obsessive-compulsive disorder treatment may not result in a cure, but it can help bring symptoms under control so that they don't rule your daily life. Some people need treatment for the rest of their lives. The two main treatments for OCD are psychotherapy and medications. Often, treatment is most effective with a combination of these. Psychotherapy Cognitive behavioral therapy (CBT), a type of psychotherapy, is effective for many people with OCD. Exposure and response prevention (ERP), a type of CBT therapy, involves gradually exposing you to a feared object or obsession, such as dirt, and having you learn healthy ways to cope with your anxiety. ERP takes effort and practice, but you may enjoy a better quality of life once you learn to manage your obsessions and compulsions. Therapy may take place in individual, family or group sessions. Medications Certain psychiatric medications can help control the obsessions and compulsions of OCD. Most commonly, antidepressants are tried first. Antidepressants approved by the Food and Drug Administration (FDA) to treat OCD include: - Clomipramine (Anafranil) for adults and children 10 years and older - Fluoxetine (Prozac) for adults and children 7 years and older - Fluvoxamine for adults and children 8 years and older - Paroxetine (Paxil, Pexeva) for adults only - Sertraline (Zoloft) for adults and children 6 years and older However, your doctor may prescribe other antidepressants and psychiatric medications. Medications: What to consider Here are some issues to discuss with your doctor about medications for OCD: - Choosing a medication. In general, the goal is to effectively control symptoms at the lowest possible dosage. It's not unusual to try several drugs before finding one that works well. Your doctor might recommend more than one medication to effectively manage your symptoms. It can take weeks to months after starting a medication to notice an improvement in symptoms. - Side effects. All psychiatric medications have potential side effects. Talk to your doctor about possible side effects and about any health monitoring needed while taking psychiatric drugs. And let your doctor know if you experience troubling side effects. - Suicide risk. Most antidepressants are generally safe, but the FDA requires that all antidepressants carry black box warnings, the strictest warnings for prescriptions. In some cases, children, teenagers and young adults under 25 may have an increase in suicidal thoughts or behavior when taking antidepressants, especially in the first few weeks after starting or when the dose is changed. If suicidal thoughts occur, immediately contact your doctor or get emergency help. Keep in mind that antidepressants are more likely to reduce suicide risk in the long run by improving mood. - Interactions with other substances. When taking an antidepressant, tell your doctor about any other prescription or over-the-counter medications, herbs or other supplements you take. Some antidepressants can cause dangerous reactions when combined with certain medications or herbal supplements. - Stopping antidepressants. Antidepressants aren't considered addictive, but sometimes physical dependence (which is different from addiction) can occur. So stopping treatment abruptly or missing several doses can cause withdrawal-like symptoms, sometimes called discontinuation syndrome. Don't stop taking your medication without talking to your doctor, even if you're feeling better - you may have a relapse of OCD symptoms. Work with your doctor to gradually and safely decrease your dose. Talk to your doctor about the risks and benefits of using specific medications. Other treatment Sometimes, medications and psychotherapy aren't effective enough to control OCD symptoms. Research continues on the potential effectiveness of deep brain stimulation (DBS) for treating OCD that doesn't respond to traditional treatment approaches. Because DBS hasn't been thoroughly tested for use in treating OCD, make sure you understand all the pros and cons and possible health risks. Lifestyle and home remedies Obsessive-compulsive disorder is a chronic condition, which means it may always be part of your life. While OCD warrants treatment by a professional, you can do some things for yourself to build on your treatment plan: - Take your medications as directed. Even if you're feeling well, resist any temptation to skip your medications. If you stop, OCD symptoms are likely to return. - Pay attention to warning signs. You and your doctor may have identified issues that can trigger your OCD symptoms. Make a plan so that you know what to do if symptoms return. Contact your doctor or therapist if you notice any changes in symptoms or how you feel. - Check first before taking other medications. Contact the doctor who's treating you for OCD before you take medications prescribed by another doctor or before taking any over-the-counter medications, vitamins, herbal remedies or other supplements to avoid possible interactions. - Practice what you learn. Work with your mental health professional to identify techniques and skills that help manage symptoms, and practice these regularly. 

Answer: The causes of obsessive-compulsive disorder are unknown. The risk factors may be the  changes in the body's own natural chemistry or brain functions; genetics; and environmental factors such as infections.