Cannabinoids are the costituents of the marijuana plants. The central effects of exogenous cannabinoids are implicated in enhancing mood, altering emotional states, and interfering in the formation of short-term memory. Cannabinoid receptors are G protein-coupled receptors with seven transmembrane domains that are expressed on the cell surface with their binding domain exposed to the extracellular space. To date, two cannabinoid receptors have been cloned, CB1 and CB2. Recent evidence suggests that a third 'CB3' receptor may be cloned in the near future. The endocannabinoids may represent the first members of a new classes of neuromodulators, that are not stored in cell vesicles, but rather synthesised by the cell on demand. The endogenous cannabinoid system could play a central role in several neuropsychiatric disorders and is also involved in other conditions such as pain, spasticity and neuroprotection. Implication of cannabinoid system in the pathogenesis and development of schizophrenia is also discussed.

The aim of this study was to retrospectively evaluate the role of C-reactive protein, total cholesterol and high-density lipoprotein cholesterol in patients suffering from Major Depression (MD). Data of C-reactive protein, total cholesterol (TC) and high-density lipoprotein cholesterol of 37 adult outpatients (17 men, 20 women) with a DSM-IV diagnosis of MD were analyzed. Depression was measured with the 17-item Hamilton Depression Rating Scale (HAM-D) and with the Beck Depression Inventory (BDI). Suicide risk was evaluated with the Scale of Suicide Ideation (SSI). Patients with a lifetime history of attempted suicide were categorized as having higher suicide risk. Higher suicide risk patients showed higher C-reactive protein levels and lower high-density lipoprotein cholesterol levels than lower suicide risk patients whereas total cholesterol levels were not statistically different. C-reactive protein positively correlated with BDI, HAM-D, SSI scores and with number of previous depressive episodes. High-density lipoprotein cholesterol correlated inversely with BDI, HAM-D and SSI scores, whereas, no significant correlations were found between Total Cholesterol and other variables including C-reactive protein. In linear regression models, C-reactive protein was predictor of more severe depression and increased suicide risk. Lower high-density lipoprotein cholesterol levels were significantly predictive of increased suicide risk.