Beyond insomnia: diagnostic discordance and pharmacotherapy in a preliminary psychiatric sleep clinic cohort

Background:

Sleep complaints typically present first to primary or secondary care, where clinical impressions form before referral to specialist services [1,2]. Whether these impressions align with diagnoses confirmed at tertiary sleep clinics—through clinical interview, validated scales and polysomnography (PSG)—and how they shape psychopharmacological prescribing in patients with high psychiatric comorbidity remains insufficiently characterized [3–5]. This study aimed to to evaluate, in a tertiary sleep clinic cohort with high psychiatric comorbidity: (i) agreement between referral impression and diagnoses confirmed after comprehensive sleep evaluation; (ii) associations between confirmed diagnosis category, diagnostic test utilization and pharmacotherapy initiation; and (iii) patterns of pharmacological and non-pharmacological management during follow-up.

Methods:

Retrospective single-centre analysis of patients referred to a tertiary sleep clinic (February 2024–December 2025). Total of 385 referred patients were screened, and 26 were included with complete clinical, diagnostic and 6-month follow-up data. Referring clinician impression was compared with diagnoses confirmed after comprehensive tertiary evaluation—clinical interview, validated sleep scales, polysomnography (PSG) and additional objective testing—classified per The International Classification of Sleep Disorders-3-TR [4]. Demographics, referring service, primary complaint, prescribed psychotropics and follow-up status were extracted. Diagnostic agreement was assessed with Cohen’s kappa; Fisher’s exact test for categorical and Mann–Whitney U for continuous variables. Two-sided p<0.05 was significant. Local ethics committee approval was obtained(AEŞH-BADEK1-2025-771).

Results:

Mean age was 46.6 ± 17.2 years; 69.2% female (n=18). Psychiatric comorbidity was present in 80.8% (n=21), most frequently anxiety (n=11) and depressive disorders (n=4). Referral impression showed κ=0.52 for insomnia, κ=0.21 for obstructive sleep apnea (OSA) and κ=0.00 for hypersomnia—all five referral hypersomnia cases received different final diagnoses. Five patients (19.2%) received a new OSA diagnosis. Eight (30.8%) had dual sleep diagnoses, most commonly insomnia plus OSA, and final diagnoses also included parasomnia and circadian rhythm sleep–wake disorders. PSG was performed in 100% of OSA-positive vs 47% of OSA-negative patients (p=0.023); electroencephalography in 73% vs 7% of parasomnia-positive vs negative patients (p=0.001). Pharmacotherapy was initiated in 73.1% (n=19); selective serotonin reuptake inhibitors (SSRIs) predominated (n=12, 46.2%). Insomnia-positive patients received pharmacotherapy more frequently (92.9% vs 50.0%; odds ratio 13.0; p=0.026). Non-pharmacological interventions which are sleep hygiene, behavioural recommendations and cognitive-behavioural therapy for insomnia-informed strategies were applied in most patients. At 6 months, 76.9% remained engaged in care and 61.5% achieved partial or full remission.

Conclusions:

This preliminary cohort represents a small subset of our sleep clinic population, yet revealed clinically noteworthy patterns. Referral impressions showed limited concordance with tertiary diagnoses, particularly for hypersomnia. The complete reassignment of hypersomnia referrals suggests a “hypersomnia paradox”, in which excessive daytime sleepiness may represent a non-specific phenomenological presentation rather than a stable diagnostic endpoint in psychiatric sleep populations [4]. In addition, insomnia-related presentations yielded heterogeneous final diagnoses, including OSA, parasomnia, circadian rhythm disorders and dual diagnoses. These findings highlight the importance of objective specialist evaluation before sleep-targeted psychotropic prescribing [2]. Pharmacotherapy, predominantly SSRIs, was delivered within a multidimensional care model including sleep hygiene, behavioural recommendations and CBT-I-informed strategies [3,5]. Overall, these hypothesis-generating findings require confirmation in the full cohort and future replication studies.

References

References

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4. American Academy of Sleep Medicine. International Classification of Sleep Disorders, third edition, text revision (ICSD-3-TR). Darien, IL: American Academy of Sleep Medicine; 2023.
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