Differentials
Major depressive disorder
SIGNS / SYMPTOMS
A major depressive episode is defined as having 5 of 9 symptoms (by DSM-5-TR) present nearly every day for 2 weeks or longer.
In persistent depressive disorder (PDD) with persistent major depressive episode, the symptoms are present nearly every day for 2 years or more.
INVESTIGATIONS
Clinical diagnosis.
Meets DSM-5-TR diagnostic criteria for major depressive disorder.
Major depressive disorder diagnosis requires less than 2 year duration, versus ≥2 years duration for persistent depressive disorder. Patients with PDD may have past or current episodes of major depression, but should not be without symptoms for more than 2 months at a time.
Bipolar disorders (bipolar I, bipolar II, bipolar disorder not otherwise specified)
SIGNS / SYMPTOMS
Manic, hypomanic, or mixed episodes.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Cyclothymic disorder
SIGNS / SYMPTOMS
Recurrent mood disturbances between hypomania and dysthymic mood.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Chronic psychosis (schizophrenia or delusional disorder)
SIGNS / SYMPTOMS
Auditory hallucinations, thought disorder, delusions, demotivation, self-neglect, and reduced emotion.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Mood disorder due to substance abuse/alcohol abuse
SIGNS / SYMPTOMS
Patients often report insomnia, nightmares, poor memory, and nervousness.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria. Urine toxicology and serum metabolic profile can provide data of current substance use and hepatic and other somatic effects.
Depressive disorder, other specified type
SIGNS / SYMPTOMS
If the criteria for persistent depressive disorder, major depression, bipolar disorder, or any other mood disorder are not met.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Anxiety disorder
SIGNS / SYMPTOMS
Excessive worry, muscular tension, fatigue, autonomic hyperactivity, and increased vigilance.
Anxiety disorders are frequently comorbid with mood disorders. If the anxiety disorder is 'primary', which means it came before the mood disorder, then the mood disorder would be 'secondary'.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Obsessive-compulsive disorder
SIGNS / SYMPTOMS
Repetitive patterns of behaviour; disturbing and intrusive thoughts; images or impulses that are generally seen by the patient as excessive, irrational, and ego-alien.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Medical illness (e.g., hypothyroidism, diabetes mellitus, HIV infection, cancer, Lyme disease)
SIGNS / SYMPTOMS
Clinical presentation variable depending on specific condition, but may include: fever, wasting, arthralgias.
Alternatively, there may be no differentiating signs and symptoms on physical and psychiatric examination.
INVESTIGATIONS
Medical evaluation including serum metabolic profile, thyroid function tests, HIV testing, and serology titres for Lyme disease may be positive/abnormal depending on specific condition.
Personality disorder
SIGNS / SYMPTOMS
Individuals meeting DSM-5-TR criteria for personality disorders such as borderline personality or narcissistic personality may present with chronic dysphoria, suicidality, sleep impairment and other depressive symptoms. Clear presence of DSM-5-TR personality disorder diagnosis features can help to clarify whether the mood disorder is the primary diagnosis.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
Somatic symptom disorder
SIGNS / SYMPTOMS
Primary presentation focused on somatic symptoms, including excessive thoughts, feelings or behaviours related to symptoms, including pain.
INVESTIGATIONS
Clinical diagnosis using DSM-5-TR criteria.
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