Major depressive disorder and persistent depressive disorder (dysthymia): Clinical sciences

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Introduction0:00–0:28

Depression is a state of persistent sadness that affects how a person thinks, feels, and behaves. It can cause significant personal distress, strain relationships, and impair daily functioning.
Additionally, depression significantly increases the risk of self-harm and suicidality. Depressive disorders include major depression and persistent depressive disorder, also known as dysthymia.
When a patient presents with a chief concern suggesting a depressive disorder, first perform a safety assessment. Assess for features of psychosis like agitation, paranoia, aggression, hallucinations, and other forms of disorganized thoughts, speech, or behavior.

Safety assessment0:28–1:31

Additionally, look for signs of catatonia, such as slow movements, holding odd poses, and minimal response to external stimuli, which can be accompanied by severe dehydration or malnutrition.
Finally, assess specifically for homicidal and suicidal ideation, paying attention to the intensity and intention, as evidenced by plans and behaviors.
If any of these features are present, the patient is at high risk of harm to self and others and requires acute management.
Your management might include psychiatric hospitalization, medical and pharmacologic stabilization, and a one-to-one sitter, if appropriate.
In severe, persistent treatment-resistant or life-threatening cases, electroconvulsive therapy might be necessary. On the other hand, if the patient is at low risk of harm to self and others, your next step is to obtain a focused history and physical exam.

History and Physical examination1:31–2:40

History usually reveals persistently sad, depressed, or hopeless mood, with decreased energy, and a lack interest and motivation that is significantly different from their baseline.
On exam, the patient might exhibit poor posture, slow speech and movements, with a flat or tearful affect. Additionally, you might see signs of inattention and memory difficulties affecting focus, recalling information, and performing tasks that require mental effort.
These findings should lead you to suspect a depressive disorder. Here’s a clinical pearl!
During the history and exam, look for signs that suggest your patient's depressive symptoms are attributed to a medical condition or substance use.
For example, hypothyroidism or a chronic pain disorder can mimic symptoms of depression. Additionally, intoxication or withdrawal from substances such as alcohol, cocaine, amphetamines, opioids, and benzodiazepines can lead to mood disturbances.

Major depressive disorder2:40–4:09

Next, assess for a current or past major depressive episode using the DSM-5 criteria. Major depressive episodes are characterized by a persistent depressed mood which can be described as sadness, emptiness, and hopelessness.
Additionally, there must be at least 4 of the following symptoms, which can be remembered using the SIG-E-CAPS mnemonic.
These include too much or too little Sleep; lack of Interest or pleasure in previously enjoyed activities such as social withdrawal or decreased sexual drive; Guilt and feelings of worthlessness; decreased Energy; poor Concentration; changes in Appetite; Psychomotor slowing or agitation; and Suicidality with recurrent thoughts of death, including passive thinking, active planning and intention, and actual behaviors such as suicide attempts.
Keep in mind, there might also be psychotic features like hallucinations or delusions. These symptoms must last 2 weeks or more and cause clinically significant distress or impairment.
If all these criteria are met, diagnose major depressive disorder, or MDD. Here’s another clinical pearl!
Individuals with major depressive disorder have experienced at least 1 major depressive episode and have never experienced a manic or hypomanic episode.
While the depressive symptoms in MDD usually improve with time and effective treatment, episodes are likely to recur. Once MDD has been diagnosed, assess symptom severity using the PHQ-9 or another validated tool.

Assess for severity4:09–4:41

The PHQ-9, or patient health questionnaire, asks the patient how often they have experienced the 9 depressive symptoms during the past 2 weeks.
Responses are rated on a scale of not at all, several days, more than half the days, or nearly every day. The numeric score from the PHQ-9 ranges from 0, for no symptoms, to 27 indicating all 9 symptoms occur nearly every day.

Mild MDD4:41–5:51

A patient experiencing 5 depressive symptoms, with a PHQ-9 score between 5 and 9, minimal functional impairment, and no suicidal ideation, can be diagnosed with mild MDD.
Management includes frequent follow-up visits and lifestyle changes, such as a healthy diet, exercise, sunlight exposure, and good sleep hygiene.
Psychotherapy can also be beneficial. Here’s a clinical pearl!
Psychotherapy plays a vital role in managing depression by promoting self-understanding and providing healthier coping strategies.
Many types of psychotherapy exist, including cognitive-behavioral therapy, or CBT, which focuses on identifying and replacing negative thought patterns and maladaptive behaviors.
Mindfulness-based cognitive therapy, or MBCT, integrates mindfulness practices with CBT. Interpersonal therapy, or IPT, concentrates on improving relationships and building social support, while psychodynamic therapy focuses on unconscious conflicts by exploring the individual’s past.
Each approach offers unique strategies and should be tailored to the individual. Next, a patient experiencing 5 or 6 depressive symptoms, with a PHQ-9 score between 10 and 19, moderate functional impairment, and possibly passive suicidal ideation can be diagnosed with moderate MDD.

Moderate MDD5:51–7:36

The initial treatment for moderate depression includes an antidepressant, typically a selective serotonin reuptake inhibitor, or SSRI, such as sertraline or fluoxetine, which can be combined with psychotherapy.
Dual treatment with an SSRI and psychotherapy is often more effective than either modality alone. If pharmacotherapy is effective, continue for at least 6 months to prevent recurrence.
Here’s a high-yield fact! Serotonin syndrome, also known as serotonin toxicity, is a potentially life-threatening condition caused by excess serotonin in the brain.
Symptoms include fever, hypertension, tachycardia, muscle rigidity, tremor or myoclonus, hyperreflexia, diaphoresis, confusion, and even seizures in severe cases.
The most common cause of serotonin syndrome is the initiation, dose increase, or switch between antidepressants that affect serotonin levels, such as SSRIs, serotonin and norepinephrine reuptake inhibitors or SNRIs, tricyclic antidepressants or TCAs, and monoamine oxidase inhibitors or MAOIs for short.
Additionally, serotonin syndrome can be caused by intentional overdose with prescribed antidepressants. The most important step in the acute management of serotonin syndrome is to discontinue the serotonergic medications immediately, followed by supportive care.

Severe MDD7:36–9:40

Finally, a patient experiencing 7 or more depressive symptoms, with a PHQ-9 score of 20 or more, severe functional impairment, and possibly active suicidal ideation or psychotic features, can be diagnosed with severe MDD.
The first-line treatment for severe depression starts with an SSRI or SNRI, such as venlafaxine or duloxetine, combined with psychotherapy.
If monotherapy with one medication is ineffective, you can add a second-generation antipsychotic like aripiprazole or quetiapine.
If there is still no improvement, consider switching to other classes of antidepressants. These include atypical antidepressants like bupropion and mirtazapine, TCA such as amitriptyline, or MAOI like phenelzine.
For severe treatment-resistant MDD, consider transcranial magnetic stimulation or TMS, electroconvulsive therapy or ECT, or emerging psychedelics like ketamine or psilocybin.
If pharmacotherapy is effective, continue for at least 6 months to prevent recurrence. Here’s another clinical pearl!
In psychiatry, treatment resistance refers to a mental health condition that does not improve or worsens despite treatment with appropriate medications.
Fortunately, in cases of severe treatment-resistant depression, alternative management options are available. Neurostimulation therapies include TMS which uses magnetic pulses to stimulate nerve cells in the brain, and ECT which uses electricity to induce controlled seizures altering brain chemistry and neural circuitry.
On the other hand, experimental psychedelic treatments with ketamine, a dissociative anesthetic, and psilocybin, a compound found in certain types of mushrooms, act on serotonin and glutamate receptors in the brain to produce profound alterations in consciousness which can modify neural activity while promoting neuroplasticity.
More research is needed to understand their long-term efficacy and safety. Now that we’ve discussed major depressive disorder, let’s go back and talk about another type of depressive disorder.

Persistent depressive disorder9:40–11:29

If the patient has no history of a major depressive episode, consider persistent depressive disorder, or PDD, also known as dysthymia.
To confirm, assess for the DSM-5 criteria for PDD. This condition is characterized by a persistently depressed mood lasting at least two years in adults, or at least one year in children.
During this period, the patient is never symptom free for more than 2 months and experiences at least two additional depressive symptoms as outlined by SIG-E-CAPS.
These symptoms must cause clinically significant distress or impairment. If all criteria are met, diagnose persistent depressive disorder.
Initial treatment for PDD includes an antidepressant, typically an SSRI, which can be combined with psychotherapy. Continue pharmacotherapy for at least 6 months to prevent recurrence.
Here’s a final clinical pearl! Persistent depressive disorder can be diagnosed independently of a major depressive episode; however, if both PDD and MDD criteria are met, both conditions should be diagnosed.
Due to the potential overlap between these conditions, be sure to use specifiers to indicate symptom course and severity.
For example, when PDD occurs without a major depressive episode, specify pure dysthymic syndrome. On the other hand, specify PDD with intermittent major depressive episodes if the criteria for a major depressive episode have been met but have not lasted for 2 years, or PDD with persistent depressive episode if full criteria for a major depressive episode have been consistently met over the previous 2-year period.

Review11:29–12:10

Alright, as a quick recap... When assessing a patient with chief concern suggesting a depressive disorder, start with a safety assessment to determine if there is a risk of harm to self and others.
Then, use the DSM-5 criteria to assess for a major depressive episode. Next, using the PHQ-9, determine the severity of MDD.
Mild MDD can be managed with frequent follow-up visits and lifestyle changes, while moderate and severe MDD should be treated with an SSRI and psychotherapy.
Finally, if your patient meets DSM-5 criteria for persistent depressive disorder, treat with an SSRI and psychotherapy.
Major depressive disorder and persistent depressive disorder (dysthymia) | Osmosis