All patients must meet the diagnostic criteria for recurrent major depression or bipolar mood disorder. Seasonal affective disorder (SAD) is then a sub-type specifier used to describe temporal variations of these disorders. As such, SAD is not considered a stand-alone diagnosis or comorbid condition to recurrent major depression or bipolar disorder. Common presentations include the initiation or worsening of depressive symptoms during the autumn or winter months, and full remission during the spring or summer months, or hypo-manic or manic symptoms presenting during spring or summer months.
Circadian and neurotransmitter factors are likely to contribute to the pathophysiology of SAD, although the exact mechanism of action remains ill-understood. The suprachiasmatic nucleus (SCN) of the hypothalamus is being increasingly recognised as the 'master regulator' of several systems implicated in seasonal mood regulation. Diminished light during the autumn and winter may cause a phase shift in various circadian rhythms, including sleep-wake cycle, body temperature, hormone levels, and melatonin secretion.
There were 2,811 deaths in Australia in 2013 where the deceased person was identified as Indigenous. The age-standardised death rate of 9.6 per 1,000 population for Indigenous people was 1.7 times the rate for their non-Indigenous counterparts.More detailed information about death rates is available for the five-year period 2006-2010 for people living in NSW, Qld, WA, SA and the NT . After age-adjustment, the death rate for Indigenous people living in those jurisdictions was 1.9 times the rate for non-Indigenous people .The rates for Indigenous people were highest in the NT (1,541 per 100,000) and WA (1,431 per 100,000).