Unrecognized depressive disorder may slow recovery and worsen prognosis in physical illness, therefore it is important that all doctors be able to recognize the condition, treat the less severe cases, and identify those requiring specialist care.Diagnosticians recognize several subtypes or course specifiers:Atypical depression (AD) is characterized by mood reactivity (paradoxical anhedonia) and positivity,  significant weight gain or increased appetite ("comfort eating"), excessive sleep or somnolence (hypersomnia), a sensation of heaviness in limbs known as leaden paralysis, and significant social impairment as a consequence of hypersensitivity to perceived interpersonal rejection. Difficulties in measuring this subtype have led to questions of its validity and prevalence.Melancholic depression is characterized by a loss of pleasure (anhedonia) in most or all activities, a failure of reactivity to pleasurable stimuli, a quality of depressed mood more pronounced than that of grief or loss, a worsening of symptoms in the morning hours, early-morning waking, psychomotor retardation, excessive weight loss (not to be confused with anorexia nervosa), or excessive guilt.Psychotic major depression (PMD), or simply psychotic depression, is the term for a major depressive episode, in particular of melancholic nature, wherein the patient experiences psychotic symptoms such as delusions or, less commonly, hallucinations. These are most commonly mood-congruent (content coincident with depressive themes).Catatonic depression is a rare and severe form of major depression involving disturbances of motor behavior and other symptoms. Here, the person is mute and almost stuporose, and either is immobile or exhibits purposeless or even bizarre movements.
High rates of suicide also occur in those who have alcohol-related problems. It is usually possible to differentiate between alcohol-related depression and depression that is not related to alcohol intake by taking a careful history of the patient. Depression and other mental health problems associated with alcohol misuse may be due to distortion of brain chemistry, as they tend to improve on their own after a period of abstinence. Benzodiazepine-induced
Benzodiazepines, such as alprazolam, clonazepam, lorazepam and diazepam, can cause both depression and mania.Benzodiazepines are a class of medication commonly used to treat anxiety, panic attacks and insomnia, and are also commonly misused and abused. Those with anxiety, panic and sleep problems commonly have negative emotions and thoughts, depression, suicidal ideations, and often have comorbid depressive disorders. While the anxiolytic and hypnotic effects of benzodiazepines disappear as tolerance develops, depression and impulsivity with high suicidal risk commonly persist. These symptoms are "often interpreted as an exacerbation or as a natural evolution of previous disorders and the chronic use of sedatives is overlooked". Benzodiazepines do not prevent the development of depression, can exacerbate preexisting depression, can cause depression in those with no history of it, and can lead to suicide attempts. Risk factors for suicide and suicide attempts while using benzodiazepines include high dose prescriptions (even in those not misusing the medications), benzodiazepine intoxication, and underlying depression.The long-term use of benzodiazepines may have a similar effect on the brain as alcohol, and are also implicated in depression.