Panic disorder is an anxiety disorder characterized by recurring severe panic attacks. It may also include significant behavioral changes lasting at least a month and of ongoing worry about the implications or concern about having other attacks. The latter are called anticipatory attacks (DSM-IVR). Panic disorder is not the same as agoraphobia (fear of public places), although many afflicted with panic disorder also suffer from agoraphobia. Panic attacks cannot be predicted, therefore an individual may become stressed, anxious or worried wondering when the next panic attack will occur. Panic disorder may be differentiated as a medical condition, or chemical imbalance. The DSM-IV-TR describes panic disorder and anxiety differently. Whereas anxiety is preceded by chronic stressors which build to reactions of moderate intensity that can last for days, weeks or months, panic attacks are acute events triggered by a sudden, out-of-the-blue cause: duration is short and symptoms are more intense. Panic attacks can occur in children, as well as adults. Panic in young people may be particularly distressing because children tend to have less insight about what is happening, and parents are also likely to experience distress when attacks occur.
Screening tools like Panic Disorder Severity Scale can be used to detect possible cases of disorder, and suggest the need for a formal diagnostic assessment.
Substance dependence, commonly called drug addiction, is a compulsive need to use drugs in order to function normally. When such substances are unobtainable, the user suffers from withdrawal.
The section about substance dependence in the Diagnostic and Statistical Manual of Mental Disorders (more specifically, the 2000 "text revision", the DSM-IV-TR) does not use the word addiction at all. It explains:
Anxiety disorder is an umbrella term that covers several different forms of a type of common psychiatric disorder, characterized by excessive rumination, worrying, uneasiness, apprehension and fear about future uncertainties either based on real or imagined events, which may affect both physical and psychological health. The disorders once classified as neuroses are now considered anxiety disorders. There are numerous psychiatric and medical syndromes which may mimic the symptoms of an anxiety disorder such as hyperthyroidism which may be misdiagnosed as generalized anxiety disorder.
Individuals diagnosed with an anxiety disorder may be classified in one of two categories; based on whether they experience continuous or episodic symptoms.