Depressive disorders

Major depressive disorder (MDD) is characterised by a period of at least two weeks during which an individual displays either low mood, or diminished interest or pleasure.^{[APA, 2013, pg. 163]} There is a collection of associated symptoms, some of which must also be present, that constitute the diagnostic criteria for MDD, including weight changes, insomnia, psychomotor changes, fatigue, feelings of worthlessness, cognitive dysfunction, and recurrent thoughts of death.^{[APA, 2013, pg. 163]}

As is noted on the slide, some of the diagnostic criteria for schizophrenia overlap with those for MDD, particularly MDD with psychotic or catatonic features.^{[APA, 2013]} To distinguish the two, the temporal relationship between the mood disturbance and the psychosis should be considered; if the delusions or hallucinations occur exclusively during a depressive episode, then the diagnosis is MDD with psychotic features (or bipolar with psychotic features, if that diagnosis more accurately reflects the symptoms).^{[APA, 2013, pg. 104]}

References:
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition (DSM-5™). © American Psychiatric Association, 2013.

Buckley PF, Miller BJ, Lehrer DS, Castle DJ. Psychiatric comorbidities and schizophrenia. Schizophr Bull 2009; 35 (2): 383–402.

Chiappelli J, Kochunov P, DeRiso K, et al. Testing trait depression as a potential clinical domain in schizophrenia. Schizophr Res 2014; 159 (1): 243–248.

Fenton WS. Depression, suicide, and suicide prevention in schizophrenia. Suicide Life Threat Behav 2000; 30 (1): 34–49.

Ferrari AJ, Charlson FJ, Norman RE, et al. The epidemiological modelling of major depressive disorder: application for the global burden of disease study 2010. PLoS One 2013; 8 (7): e69637.

Goodwin GM. Depression and associated physical diseases and symptoms. Dialogues Clin Neurosci 2006; 8 (2): 259–265.

Martin RL, Cloninger CR, Guze SB, Clayton PJ. Frequency and differential diagnosis of depressive syndromes in schizophrenia. J Clin Psychiatry 1985; 46 (11 Pt 2): 9–13.