Organic Mood Disorder:
Organic mood disorders are characterized by those that involve the moods or emotions of a person that are changed due to a physiological problem with the brain or nervous system. 
Disorders characterized by a change in mood or affect, usually accompanied by a change in the overall level of activity, depressive, hypomanic, manic or bipolar, but arising as a consequence of an organic disorder. 
The major theme of an organic mood disorder is that it has an effect on the mood and emotions of an individual. These changes are caused by a physical problem with the brain. There are two main types of organic mood disorders – those that involve only depression for extended periods of time and those that involve going from depression to mania and back.
Many psychotherapy programs have been developed specifically to help with organic mood disorders. 
According to ICD-10 (F06.3), presence of prominent and persistent mood disturbance caused by an underlying organic cause is required for the diagnosis of organic mood disorder, in addition to the general guidelines for the diagnosis of other organic mental disorders, described earlier. It is important to rule out any major disturbance of consciousness, orientation, or memory.
The mood disturbance can be a major depressive episode, a manic episode, or a mixed affective episode. The severity may vary from mild to severe. 
Sign & Symptoms:
- Extreme changes in personality
- Prolonged depression
- Easy irritability and agitation
- Extreme aggression
- Extreme anxiety 
Some of the causes of organic mood disorder are listed below:
- Mania: INH, Levodopa, Bromide, LSD, Corticosteroids (hypomania), Hallucinogens, Tricyclic antidepressants, Cocaine, Baclofen, Amphetamines, Bromocriptine, Cimetidine, Procyclidine
- Depression: Reserpine, Ethanol, Clonidine, Methyldopa, Propranolol, Corticosteroids, Antipsychotics (particularly typical antipsychotics), Cimetidine, Anticancer chemo therapy, Oral contraceptives. Any drug a depressed person is taking should be considered a potential factor in the causation of depressive episode.
2. Endocrine disorders:
Depression: Hypothyroidism, Cushing’s syndrome, Addison’s disease, hyper and hypoparathyroidism.
3. CNS disorders:
Parkinsonism, Huntington’s chorea, PSP (progressive supranuclear palsy; depression more likely), CVAs (cerebrovascular accidents; left-sided anterior lesions and right sided posterior lesions cause depression in stroke), cerebral tumours, epilepsy (complex partial seizures), neurosyphilis (GPI), head injury (mania more likely), multiple sclerosis.
4. Post-viral illnesses:
Inﬂuenza, infectious mononucleosis, viral pneumonia, infectious hepatitis.
Pellagra, deﬁciency of thiamine, folate, niacin, folate, B12.
Carcinoma pancreas (depression), SLE, pernicious anaemia, temporal arteritis (depression), carcinoid syndrome (mania). 
These are the two major types of mood disorders.
- Depressive disorders concern feelings of hopelessness and other negative emotions associated with depression. There are varying degrees of problems with depression, ranging from Major Depressive disorder (with several sub-varieties) to chronic cases of depression labeled dysthymia, where a person has a continual low mood for more than 24 months at a time.
- Bipolar disorders include depression – including any of the different varieties of depression – but people affected also exhibit manic episodes on the other end of the emotional spectrum. Some go back and forth between extremes multiple times very rapidly depending on the degree of the disorder. 
1. Management of the underlying organic cause, if treatable.
2. Symptomatic management, if the episodes are severe.
For example, for a manic episode, low dose antipsychotic medication (such as risperidone, haloperidol, olanzapine) and/or a mood stabiliser (such as valproate); and for a depressive episode, low dose antidepressants (such as sertraline or mirtazapine). Antipsychotics are not recommend in patients who have suffered from stroke and/or dementia as the risk of mortality is higher.
Pathological laughter and crying (associated with multiple sclerosis or stroke) can similarly respond to small dose SSRIs or small dose amitriptyline.