Although brain tissue samples are the most accurate way to determine diagnosis, this is only done during autopsies. Brain scans, including both fMRIs and CTs, are some of the most accurate and non-invasive modes of diagnosis. Combined with conversation analysis, specialists are able to connect particular neurological degeneration with inappropriate social behavior and cognition.

The DSM-V marked the first time that the manual included "symptom severity" in the assessment of many psychiatric disorders, including substance use and autism. All of the other statements are false. The DSM-5 is predominantly used in the United States, does not have axes (the DSM-IV did), it is highly criticized by most healthcare professions, and can be used in assessing children, adolescents, and adults.

Post-traumatic stress disorder is an anxiety disorder that can occur following the subject witnessing or experiencing of a traumatic event (e.g. war, famine, death). All of the other answer choices are mood disorders, which entail a serious change in mood.

Clinicians take into account all three of these factors when diagnosing mental illness. Deviance refers to behavior or beliefs that are substantially different (deviant) from the majority of people in that society or culture. Maladaptive behavior refers to behavior that is not healthy or in some way harms them. Personal distress is also taken into account and is a subjective report of how much the patient is upset.

Diagnosis involves determining what illness a patient might have, usually accomplished by comparing the patient's reported symptoms with a set of criteria for a particular illness. Prognosis sounds similar but is actually a forecast about the probably course of an illness. Etiology refers to the apparent causation and development of illnesses. Epidemiology is an area of study that involves the incidence, prevalence, and distribution of illnesses.

Current classification systems are categorical in nature, meaning that there are distinct categories for each mental illness that does not necessarily overlap with other diagnoses. A dimensional system that takes into account the overlapping nature of mental illness along a spectrum of severity has been proposed, but it has limited utility.

Generalized Anxiety Disorder (GAD) is a disorder marked by excessive worry about multiple domains within one's life. These worries greatly distress an affected individual, and interfere with normal functioning. GAD is also accompanied by several physical symptoms including restlessness, decreased sleep, muscle tension, and weakness.

BPD's main symptoms involve turbulent relationships, extreme emotional reactions to everyday situations and self-harm. It is usually comorbid with anxiety and/or depression. Additionally, BPD patients have been reported as very difficult to treat (in comparison to other psychological disorders). This is because the typical subject is resistant to intervention.

Exact causes have not yet been confirmed, but there are currently many risk factors that have been linked. Alzheimer's, for example, is linked to several genetic polymorphisms. APOE-e4 has the strongest correlation so far, but not everyone with this genetic marker develops the disease. Some scientists believe that we have not yet identified the responsible genes.