SIGECAPS and DIG FAST: remembering the criteria for depression and mania

What the SIGECAPS letters mean

S is sleep change, either insomnia or sleeping far more than usual. I is loss of interest or pleasure in activities the person used to enjoy. G is guilt or feelings of worthlessness. E is low energy or fatigue. C is trouble concentrating or making decisions.

A is appetite or weight change in either direction. P is psychomotor agitation or slowing that other people can see. The final S is suicidal thinking: recurrent thoughts of death, a plan, or an attempt. MSD Manuals lists these with depressed mood as the nine criteria, of which at least five must be present nearly every day over the same two weeks.

What the DIG FAST letters mean

D is distractibility. I is impulsivity or indiscretion: involvement in activities with a high chance of painful consequences, such as spending sprees. Some versions read the I as irresponsibility, which points to the same behavior. G is grandiosity or inflated self-esteem. F is flight of ideas or racing thoughts.

A is increased goal-directed activity or agitation. S is a decreased need for sleep. T is talkativeness or pressured speech. MSD Manuals requires at least three of these, or four if the mood is only irritable, lasting at least a week, or any length of time if the person needs hospitalization.

When nurses use them, and where they mislead

The mnemonics help a nurse structure an assessment interview and recognize which observed behaviors count toward an episode. They are memory hooks for criteria, not screening tools. Validated instruments such as the PHQ-9 exist for depression screening, and MSD Manuals notes that even those cannot be used alone for diagnosis.

Both mnemonics leave out the gatekeeper symptom. A depressive episode needs depressed mood or loss of interest, and SIGECAPS only captures the second. A manic episode needs an abnormal, persistently elevated or irritable mood, which DIG FAST never mentions. Neither carries a time frame, so five SIGECAPS letters over three days do not describe major depression.

The line between mania and hypomania is also missing. Hypomania can show the same DIG FAST features for at least four days without psychotic features, marked impairment or hospitalization. That difference separates bipolar I from bipolar II, and the mnemonic cannot make it for you.

A worked exam scenario on a mood unit

Hypothetical scenario, not a real exam item: a client admitted with bipolar disorder has slept about two hours a night for six days, talks rapidly without pause, and has spent thousands of dollars on online purchases. During the interview the client says quietly, 'I don't really see the point of any of it.' Which finding should the nurse follow up first?

The statement about not seeing the point comes first, because it may signal suicidal thinking and needs a direct question about thoughts, plan and intent. The DIG FAST findings are tempting answers because they fit the mnemonic so neatly, and sleep loss and spending are real concerns, but they are expected features of the episode. MSD Manuals advises asking directly about self-harm thoughts and past attempts in every mood assessment.

Common traps with these two mnemonics

One trap describes a client with poor sleep, low energy and poor appetite after a recent medical illness and asks whether the findings meet criteria for depression. Several SIGECAPS letters are present, but without depressed mood or loss of interest lasting two weeks the criteria are not met, and the overlap with physical illness needs the provider's assessment.

Another trap describes a client who sleeps little but feels exhausted and wishes they could sleep. That is insomnia, a SIGECAPS finding, not the decreased need for sleep in DIG FAST. The question to ask is whether the person feels tired: a client in a manic episode typically feels rested and energetic despite very little sleep.

Sources and further reading

MSD Manual Professional Version: Depressive Disorders. The nine criteria for a major depressive episode, five over two weeks with depressed mood or loss of interest required, direct questions about self-harm, and PHQ-9 not usable alone for diagnosis.

MSD Manual Professional Version: Bipolar Disorders. Manic episode criteria (symptom list, three or four if mood only irritable, one week or hospitalization) and hypomania lasting at least four days without psychosis, marked impairment or hospitalization.